{"id":9307,"date":"2016-06-07T23:30:18","date_gmt":"2016-06-08T03:30:18","guid":{"rendered":"http:\/\/cscircles.cemc.uwaterloo.ca\/?page_id=9307"},"modified":"2017-06-28T19:25:40","modified_gmt":"2017-06-28T23:25:40","slug":"zh-17","status":"publish","type":"page","link":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/zh-17\/","title":{"rendered":"17: \u5b58\u5728"},"content":{"rendered":"<!-- Please retain this notice and add more notes if you create a new version.<br \/>\nOriginal lesson author: David Pritchard, daveagp@gmail.com, http:\/\/cscircles.ca<br \/>\nLicense: http:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/-->\n<p>\u8fd9\u8282\u8bfe\u63d0\u4f9b\u66f4\u591a\u6709\u5173Python\u50a8\u5b58\u5e8f\u5217\u7684\u4fe1\u606f\u3002\u590d\u5236\u5e76\u6bd4\u8f83\u5e8f\u5217\u4f1a\u6709\u9884\u6599\u4e4b\u5916\u7684\u7ed3\u679c\u3002\u6211\u4eec\u4f1a\u89e3\u91caPython\u5185\u90e8\u662f\u5982\u4f55\u8fd0\u884c\u7684\uff0c\u8ba9\u4f60\u7406\u89e3\u5e76\u907f\u514d\u8fd9\u4e9b\u9519\u8bef\u3002\u6bd4\u5982\uff0c\u4e00\u4e2a\u666e\u904d\u7684\u95ee\u9898\u662f\u51e0\u4e2a\u4e0d\u540c\u7684\u53d8\u91cf\u4f1a\u201c\u8868\u660e\u201d\u6216\u201c\u6307\u5411\u201d\u76f8\u540c\u7684\u5e8f\u5217\u3002\u8fd9\u8282\u8bfe\u7684\u672b\u5c3e\u6211\u4eec\u4f1a\u5f15\u5165\"<code>is<\/code>\"\u8fd0\u7b97\u7b26\u3002\u8fd9\u4e2a\u8fd0\u7b97\u7b26\u662f\u7528\u6765\u5224\u65ad\u662f\u5426\u591a\u4e2a\u53d8\u91cf<em>\u786e\u5b9e<\/em>\u6307\u5411\u540c\u4e00\u4e2a\u5e8f\u5217\u3002<\/p>\n<h1>\u8303\u4f8b<\/h1>\n<p>\u6211\u4eec\u60f3\u8981\u4e00\u4e32\u4ee3\u7801\uff0c\u5c06\u4e00\u4e2a\u82f1\u5c3a\u4e3a\u5355\u4f4d\u7684\u957f\u5ea6\u5e8f\u5217<code>oldSize<\/code>\u8f6c\u53d8\u4e3a\u4e00\u4e2a\u4ee5\u5398\u7c73\u4e3a\u5355\u4f4d\u7684\u957f\u5ea6\u5e8f\u5217<code>newSize<\/code>\u3002\u5176\u4e2d\u4e00\u79cd\u65b9\u5f0f\u662f\u4f7f\u7528<code>newSize = oldSize<\/code>\u6765\u5efa\u7acb\u4e00\u4efd\u526f\u672c\uff0c\u7136\u540e\u63a5\u7740\u5f80\u4e0b\u6539\u53d8\u6240\u6709\u7684\u503c\uff1a<\/p>\n<pre>oldSize = [\"letter\", 8.5, 11] \u00a0 # size of paper in inches\r\nnewSize =\u00a0oldSize \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 # make a copy?\r\nnewSize[1] = newSize[1]*2.54 \u00a0 \u00a0# convert to cm\r\nnewSize[2] = newSize[2]*2.54 \u00a0 \u00a0# convert to cm<\/pre>\u73b0\u5728\u8ba9\u6211\u4eec\u770b\u770b\u662f\u5426\u80fd\u6b63\u5e38\u8fd0\u884c\u3002\u5982\u679c\u4f60\u6253\u5370<code>newSize<\/code>\uff0c\u90a3\u4e48\u4f60\u4f1a\u5f97\u5230<code>[\"letter\", 21.59, 27.94]<\/code>\u3002\u6ce8\u610f\uff0c\u5f53\u6211\u4eec\u6253\u5370<code>oldSize<\/code>\u7684\u65f6\u5019\uff0c<code>oldSize<\/code>\u7684\u503c\u4f1a\u6539\u53d8\uff01\u4e0b\u9762\u662f\u5177\u4f53\u89e3\u91ca\uff1a<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform0\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox0'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u7b2c\u4e8c\u884c\u8f93\u51fa\u4e0d\u662f\u6211\u4eec\u60f3\u8981\u7684\uff01<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 214px;'><textarea wrap='off' name='usercode0' id='usercode0'  cols=10 rows=8 readonly='readonly'  style = 'height : 214px;'  class='pyboxCode RO'>\ndef square(x):\n    value = x * x\n    return value\n\n# \u7a0b\u5e8f\u4e3b\u4f53\u4ece\u8fd9\u91cc\u5f00\u59cb\nvalue = 17\nfivesquared = square(5)\nprint(fivesquared, value)<\/textarea><\/div>\n<div id='pbhistory0' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit0' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(0)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(0,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse0\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"0\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"fbfb781bac33589a1c1bad1a5768b59a\"\/>\n<div id='pbresults0' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit0\").value = \"Run program\";document.getElementById(\"inputInUse0\").value = \"N\";<\/script>\n<\/p>\n<p>\u6211\u4eec\u4f1a\u5728\u4e0b\u9762\u901a\u8fc7\u4f7f\u7528\u56fe\u8868\u8be6\u7ec6\u89e3\u91ca\u521a\u521a\u53d1\u751f\u4e86\u4ec0\u4e48\u3002\u5176\u5b9e\u8fd9\u91cc\u7684\u4e3b\u8981\u95ee\u9898\u662f<code>newSize = oldSize<\/code>\u6ca1\u6709\u590d\u5236\u6574\u4e2a\u5e8f\u5217\uff1a\u5b83\u53ea\u662f\u5c06<em>\u53c2\u8003<\/em>\uff08\u7bad\u5934\uff09\u590d\u5236\u5230\u4e86\u76f8\u540c\u7684\u5e8f\u5217\u4e0a\u3002<\/p>\n<p><em>\u70b9\u51fb\u6807\u9898\u6539\u53d8\u6807\u7b7e\u3002<\/em><\/p>\n<div class=\"accordion\"><br \/>\n<div class='collapseContain showing'>\n<div class='collapseHead'><span class='icon'><\/span>\nMemory\n<\/div>\n<div class='collapseBody'>\u6211\u4eec\u4f1a\u4f7f\u7528\u4e00\u4e2a\u8868\u683c\u6765\u8868\u793aPython\u5185\u5b58\u4e2d\u7684\u53d8\u91cf\u548c\u503c\u3002\u6bd4\u5982\uff0c\u5728\u8fd0\u884c\u4e0b\u5217\u4ee3\u7801\u540e<\/p>\n<pre>city = \"Moose Factory\"\r\npopulation = 2458\r\nemployer = city<\/pre>\u8fd9\u4e2a\u8868\u683c\uff08\u5e26\u9ed1\u8272\u8fb9\u6846\u7684\uff09\u5c55\u793a\u4e86Python \u7684\u5185\u5b58\uff1a<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide1-zh.png\" alt=\"\" width=\"480\" height=\"168\" \/><br\/>\u7b2c\u4e00\u4e2a\u53d8\u91cf\u7684\u540d\u5b57\u662f<code>city<\/code>\uff0c\u503c\u4e3a\u5b57\u7b26\u4e32<code>\"Moose Factory\"<\/code>\u3002\u7b2c\u4e8c\u4e2a\u53d8\u91cf\u7684\u540d\u5b57\u662f<code>population<\/code>\uff0c\u503c\u662f\u6574\u6570<code>2458<\/code>\u3002\u7b2c\u4e09\u4e2a\u53d8\u91cf\u540d\u5b57\u662f<code>employer<\/code>\uff0c\u503c\u662f\u5b57\u7b26\u4e32<code>\"Moose Factory\"<\/code>\u3002<\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\nLists in memory\n<\/div>\n<div class='collapseBody'>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u4f1a\u5c55\u793a<em>\u5e8f\u5217<\/em>\u5728\u5185\u5b58\u4e2d\u662f\u4ec0\u4e48\u6837\u7684\u3002\u6bd4\u5982\uff0c\u4e0b\u5217\u4ee3\u7801<\/p>\n<pre>myList = [\"Moose Factory\", 2458]<\/pre>\u53ea\u4f1a\u521b\u5efa\u4e00\u4e2a\u53d8\u91cf\uff0c\u540d\u4e3a<code>myList<\/code>\u3002\u4e00\u4e2a\u5e8f\u5217\u88ab\u521b\u5efa\uff0c<code>myList<\/code>\u7684\u503c\"\u6307\u5411\"\u6216\"\u5bf9\u5e94\"\u90a3\u4e2a\u5e8f\u5217\u3002\u6211\u4eec\u7528\u4e00\u4e2a\u76d2\u5b50\u4ee3\u8868\u5e8f\u5217\uff0c\u5e8f\u5217\u7684\u9879\u5728\u76d2\u5b50\u91cc\u7d27\u6328\u7740\u4ed6\u4eec\u5bf9\u5e94\u7684\u7d22\u5f15\u3002\u5e8f\u5217\u662f\u84dd\u8272\u7684\u3002<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide2-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><br\/>\u7bad\u5934\u8868\u660e<code>myList<\/code>\u6307\u5411\u65b0\u7684\u5e8f\u5217\u3002\u5e8f\u5217\u4e2d\u7d22\u5f15\u4e3a0\u7684\u90a3\u4e00\u9879\u662f\u5b57\u7b26\u4e32<code>\"Moose Factory\"<\/code>\uff0c\u7d22\u5f15\u4e3a1\u7684\u90a3\u4e00\u9879\u662f\u6574\u6570<code>2458<\/code>\u3002\u6bd4\u5982\uff0c\u5982\u679c\u4f60<code>print(myList[1])<\/code>\uff0c\u90a3\u4e48Python\u4f1a\u8f93\u51fa<code>2458<\/code>\u3002<\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\n\u66ff\u6362\u5e8f\u5217\u7684\u503c\n<\/div>\n<div class='collapseBody'>\u4e3a\u4e86\u8bf4\u5f97\u66f4\u6e05\u695a\uff0c\u6211\u4eec\u5728\u4e0a\u4e00\u4e2a\u4f8b\u5b50\u4e2d\u589e\u52a0\u4e00\u884c\u3002\u6211\u4eec\u8fd0\u884c\u4ee5\u4e0b\u4ee3\u7801<\/p>\n<pre>myList = [\"Moose Factory\", 2458]\r\nmyList[1] = myList[1]+1<\/pre>Python\u8ba1\u7b97<code>2458+1<\/code>\uff0c\u7ed3\u679c\u662f<code>2459<\/code>\uff0c\u8fd9\u4e2a\u4f1a\u66ff\u6362\u5e8f\u5217\u4e2d\u7d22\u5f15\u4e3a1\u7684\u9879\u3002\u66f4\u65b0\u540e\uff0c\u6211\u4eec\u5f97\u5230\u4ee5\u4e0b\u56fe\u8868\u3002<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide3-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><br\/>\uff08\u5212\u6389\u76842458 \u662f\u53ea\u662f\u4e3a\u4e86\u5f3a\u8c03\u8fd9\u4e2a\u6539\u53d8\u3002\uff09<\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\n<code>oldSize<\/code> and <code>newSize<\/code>\n<\/div>\n<div class='collapseBody'>\u73b0\u5728\u6211\u4eec\u56de\u5230\u7b2c\u4e00\u4e2a\u4f8b\u5b50\u4e2d\u3002\u7b2c\u4e00\u884c\u539f\u6765\u662f<\/p>\n<pre>oldSize = [\"letter\", 8.5, 11]<\/pre>\u8fd9\u4e00\u884c\u8fd0\u884c\u540e\uff0cPython\u7684\u5185\u5b58\u5c31\u5982\u4ee5\u4e0b\u56fe\u8868\u6240\u793a\u3002\u6211\u4eec\u521b\u5efa\u4e86\u4e00\u4e2a\u957f\u4e3a3\u7684\u5e8f\u5217\u3002<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide4-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\nMain problem\n<\/div>\n<div class='collapseBody'>\u5728\u6211\u4eec\u7684\u7a0b\u5e8f\u4e2d\uff0c\u7b2c\u4e8c\u884c\u662f<\/p>\n<pre>newSize = oldSize<\/pre>\u8fd9\u8282\u8bfe\u6700\u91cd\u8981\u7684\u4e00\u70b9\u662f\uff1a<strong><code>=<\/code>\u5e76\u4e0d\u590d\u5236\u5e8f\u5217\uff01<\/strong>\u76f8\u53cd\uff0c\u5b83\u53ea\u521b\u5efa\u4e86\u4e00\u4e2a\u65b0\u7684\u6307\u5411\uff0c\u6307\u5411<strong>\u540c\u4e00\u4e2a<\/strong>\u5e8f\u5217\u3002\u8fd9\u53ef\u4ee5\u7528\u4e24\u4e2a\u4e0d\u540c\u7684\u7bad\u5934\u6307\u5411<strong>\u540c\u4e00\u4e2a<\/strong>\u76d2\u5b50\u8868\u660e\u3002<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide5-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><br\/>\u5982\u4e0b\u8868\u6240\u793a\uff0c\u6211\u4eec\u6709\u4e24\u4e2a\u53d8\u91cf\uff0c\u4e24\u4e2a\u90fd\u6307\u5411\u540c\u4e00\u4e2a\u5e8f\u5217\u3002<\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\nUpdating\n<\/div>\n<div class='collapseBody'>\u63a5\u7740\uff0c\u5f53\u7a0b\u5e8f\u8fbe\u5230<\/p>\n<pre>newSize[1] = newSize[1]*2.54<\/pre>Python\u4f1a\u67e5\u770b<code>newSize<\/code>\uff0c\u67e5\u770b\u7d22\u5f15\u4e3a1\u7684\u503c(8.5)\uff0c\u5e76\u4e582.54\uff0c\u7136\u540e\u4ee3\u66ff\u539f\u6765\u7684\u503c\u3002\u7136\u800c\uff0c\u56e0\u4e3a<code>oldSize<\/code>\u6307\u5411\u76f8\u540c\u7684\u5e8f\u5217\uff0c\u6211\u4eec\u4e5f\u5f71\u54cd\u4e86<code>oldSize<\/code>\u6307\u5411\u7684\u503c\uff01<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide6-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><br\/>\uff08\u540c\u6837\uff0c\u5212\u6389\u76848.5 \u53ea\u662f\u4e3a\u4e86\u5f3a\u8c03\u8fd9\u4e2a\u6539\u53d8\u3002\uff09<\/div><\/div><div class='collapseContain hiding'>\n<div class='collapseHead'><span class='icon'><\/span>\nResult\n<\/div>\n<div class='collapseBody'>\u4e0b\u4e00\u884c\u4e5f\u662f\u540c\u6837\u7684\u9053\u7406\uff0c<\/p>\n<pre>newSize[2] = newSize[2]*2.54<\/pre>\u5f71\u54cd\u5e8f\u5217\u4e2d\u7684\u53e6\u4e00\u4e2a\u503c\u3002\u5728\u8fd9\u4e00\u884c\u8fd0\u884c\u540e\uff0cPython\u7684\u5185\u5b58\u5c31\u5982\u4e0b\u56fe\u6240\u793a\u3002<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"..\/wp-content\/lesson_files\/img\/17\/slide7-zh.png\" alt=\"\" width=\"702\" height=\"168\" \/><br\/>\u73b0\u5728\u5f53\u6211\u4eec\u6253\u5370<code>newSize<\/code><strong>\u6216<\/strong> <code>oldSize<\/code>\uff0cPython\u8f93\u51fa<code>[\"letter\", 21.59, 27.94]<\/code>\u3002<\/div><\/div><\/div><br \/>\n<table class='pywarn'><tr><td class='pywarnleft'><img src='https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-content\/plugins\/pybox\/files\/warning.png'\/><\/td><td class='pywarnright'><span> \u4e3a\u4e86\u67e5\u770b\u6ca1\u6709\u8bc4\u8bba\u7684\u56fe\u7247\uff0c<a href=\"http:\/\/cscircles.cemc.uwaterloo.ca\/visualize\/#code=oldSize%20%3D%20%5B%22letter%22%2C%208.5%2C%2011%5D%20%20%20%23%20size%20of%20paper%20in%20inches%0AnewSize%20%3D%20oldSize%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20make%20a%20copy%0AnewSize%5B1%5D%20%3D%20newSize%5B1%5D*2.54%20%20%20%20%23%20convert%20to%20cm%0AnewSize%5B2%5D%20%3D%20newSize%5B2%5D*2.54%20%20%20%20%23%20convert%20to%20cm%0Aprint(newSize)%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20as%20expected%2C%20prints%20%5B%22letter%22%2C%2021.59%2C%2027.94%5D%0Aprint(oldSize)%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20surprise!%20DOES%20NOT%20print%20%5B%22letter%22%2C%208.5%2C%2011%5D\">\u5728\u53ef\u89c6\u5316\u7a97\u53e3\u4e2d\u8fd0\u884c\u76f8\u540c\u7684\u4ee3\u7801<\/a>\u3002 <\/span><\/td><\/table><\/p>\n<p><table class='pywarn'><tr><td class='pywarnleft'><img src='https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-content\/plugins\/pybox\/files\/warning.png'\/><\/td><td class='pywarnright'><span> Python \u4e2d\u7684\u6bcf\u4e00\u4e2a\u503c\u90fd\u662f\u4f4d\u4e8e\u7279\u5b9a\u5185\u5b58\u5757\u4e2d\u7684\u5bf9\u8c61\u3002\u5e76\u4e14<em>\u6bcf\u4e2a<\/em>\u53d8\u91cf\u53ea\u662f\u4e00\u4e2a\u53c2\u8003\/\u6307\u9488\/\u7bad\u5934\u3002\u6bd4\u5982\uff0c\u5728\u7b2c\u4e00\u4e2a\u6807\u7b7e\u4e2d\uff0c\u5185\u5b58\u53ea\u5305\u542b\u4e00\u4e2a\"Moose Factory\"\uff0c\u4e24\u4e2a\u7bad\u5934\u6307\u5411\u5b83\u3002\u56e0\u4e3a\u6570\u5b57\u548c\u5b57\u7b26\u4e32\u662f\"\u4e0d\u53ef\u6539\u53d8\u7684\"\uff0c\u6211\u4eec\u5728\u8fd9\u4e9b\u8bfe\u4e2d\u4e0d\u7528\u7bad\u5934\u753b\u5b83\u4eec\u3002\u4f46\u662f\u5728\u540e\u53f0\uff0cPython\u5bf9\u6240\u6709\u7684\u6570\u636e\u4e00\u89c6\u540c\u4ec1\u3002<a href=\"http:\/\/www.greenteapress.com\/thinkpython\/html\/thinkpython011.html\">\u8be6\u60c5<\/a>\u3002 <\/span><\/td><\/table><\/p>\n<h1>Python\u4e2d\u7684\"\u6df1\u5ea6\"\u590d\u5236\u5e8f\u5217<\/h1>\n<p>\u5728\u4e0a\u8ff0\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528<code>=<\/code>\u6765\u5728\u73b0\u5b58\u7684\u5e8f\u5217\u4e2d\u521b\u5efa\u7b2c\u4e8c\u6307\u9488\/\u53c2\u8003\/\u7bad\u5934\uff0c\u901a\u5e38\u88ab\u53eb\u505a\"\u6d45\"\u590d\u5236\u3002\u5c3d\u7ba1\u5b83\u662f<a class=\"hintlink\"  id=\"hintlink1\">\u867d\u7136\u6709\u65f6\u8fd9\u4e48\u505a\u6709\u7528<\/a>\uff0c\u4f46\u5728\u6b64\u65f6\u8fd9\u5e76\u4e0d\u662f\u6211\u4eec\u60f3\u8981\u7684\u3002\u53cd\u800c\uff0c\u6211\u4eec\u60f3\u521b\u5efa\u4e00\u4e2a\u5168\u65b0\u7684\u5e8f\u5217\u526f\u672c\u3002\u90a3\u4e48\u8be5\u5982\u4f55\u5b8c\u6210\u5462\uff1f<\/p>\n<p>\u6211\u4eec\u7ed9\u51fa\u4e09\u4e2a\u7b54\u6848\u3002\u5b83\u4eec\u57fa\u672c\u4e0a\u76f8\u540c\uff0c\u4f46\u662f\u6bcf\u4e00\u4e2a\u90fd\u4f1a\u544a\u8bc9\u4f60\u4e00\u4e2a\u5173\u4e8ePython\u7684\u65b0\u77e5\u8bc6\uff0c\u6240\u4ee5\u4e09\u4e2a\u90fd\u503c\u5f97\u9605\u8bfb\u3002<\/p>\n<h2>\u65b9\u6cd51\uff0c\u4f7f\u7528<code>[:]<\/code><\/h2>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform2\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox2'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u4f7f\u7528<code>[:]<\/code>\u590d\u5236<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 110px;'><textarea wrap='off' name='usercode2' id='usercode2'  cols=10 rows=4 readonly='readonly'  style = 'height : 110px;'  class='pyboxCode RO'>\noldList = [\"first\", \"second\", \"third\"]\nnewList = oldList[:]     # create a copy\noldList.reverse()\nprint(newList, oldList)<\/textarea><\/div>\n<div id='pbhistory2' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit2' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(2)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(2,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse2\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"2\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"44a8639fa1434f2e1845c09d1ee8298d\"\/>\n<div id='pbresults2' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit2\").value = \"Run program\";document.getElementById(\"inputInUse2\").value = \"N\";<\/script>\n<\/p>\n<p>\u5728\u4e0a\u8ff0\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u8bc1\u660e\u4e86<code>newList = oldList[:]<\/code>\u521b\u5efa\u4e86\u539f\u6765\u5e8f\u5217\u7684\u526f\u672c\u3002\u5c3d\u7ba1\u8fd9\u4e2a\u53e5\u6cd5\u770b\u8d77\u6765\u5f88\u964c\u751f\uff0c\u4f46\u5176\u5b9e\u6211\u4eec\u89c1\u5230\u8fc7\u7c7b\u4f3c\u7684\u4e1c\u897f\u3002\u5728<a href=\"\/7a-strings\/\">\u5b57\u7b26\u4e32\u8bfe\u7a0b<\/a>\u4e2d\uff0c\u6211\u4eec\u4ecb\u7ecd\u4e86\u4e00\u79cd\u5206\u79bb\u5b50\u94fe\u7684\u65b9\u5f0f\uff1a<code>string[first:tail]<\/code>\u8fd4\u8fd8\u5b50\u94fe\uff0c\u4ece\u7d22\u5f15<code>first<\/code>\u5f00\u59cb\uff0c\u76f4\u5230\u7d22\u5f15<code>tail-1<\/code>\u7ed3\u675f\u3002\u6211\u4eec\u66fe\u7ecf\u63d0\u5230\u8fd9\u8fd8\u53ef\u4ee5\u5e94\u7528\u4e8e\u521b\u5efa\u5e8f\u5217\u7684\u5b50\u5e8f\u5217\u3002\u9664\u6b64\u4ee5\u5916\uff0c<\/p>\n<ul>\n<li>\u5982\u679c\u4f60\u7701\u7565<code>first<\/code>\uff0c\u7136\u540e\u53d6\u9ed8\u8ba4\u503c<code>0<\/code>\uff1b<\/li>\n<li>\u5982\u679c\u4f60\u7701\u7565<code>tail<\/code>\uff0c\u7136\u540e\u53d6<code>len<\/code>\u7684\u9ed8\u8ba4\u503c\uff08\u5e8f\u5217\/\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff09\u3002<\/li>\n<\/ul>\n<p>\u6240\u4ee5\u5b9e\u9645\u4e0a\uff0c<code>oldList[:]<\/code>\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u5b50\u5e8f\u5217\u3002\u8fd9\u4e2a\u5b50\u5e8f\u5217\u4e0e\u539f\u5e8f\u5217\u76f8\u540c\uff0c\u662f\u4e00\u4efd\u65b0\u7684\u526f\u672c\u3002<\/p>\n<h2>\u65b9\u6cd52\uff0c\u4f7f\u7528<code>copy.copy()<\/code><\/h2>\n<p>\u6709\u4e00\u4e2a\u6a21\u5757\u53eb\u505a<code>copy<\/code>\uff0c\u91cc\u9762\u6709\u51e0\u4e2a\u5173\u4e8e\u590d\u5236\u7684\u65b9\u6cd5\u3002\u6700\u7b80\u5355\u7684\u4e00\u4e2a\u53eb\u505a<code>copy.copy(L)<\/code>\uff1a\u5f53\u4f60\u5bf9\u5e8f\u5217<code>L<\/code>\u8c03\u7528\u8fd9\u4e2a\u7a0b\u5e8f\u65f6\uff0c\u7a0b\u5e8f\u4f1a\u8fd4\u8fd8<code>L<\/code>\u771f\u6b63\u7684\u526f\u672c\u3002<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform3\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox3'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u4f7f\u7528<code>copy.copy<\/code>\u590d\u5236<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 136px;'><textarea wrap='off' name='usercode3' id='usercode3'  cols=10 rows=5 readonly='readonly'  style = 'height : 136px;'  class='pyboxCode RO'>\nimport copy\noldList = [\"first\", \"second\", \"third\"]\nnewList = copy.copy(oldList)     # create a copy\noldList.reverse()\nprint(newList, oldList)<\/textarea><\/div>\n<div id='pbhistory3' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit3' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(3)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(3,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse3\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"3\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"4910619f4f5f9cf25b6847df12d1c89b\"\/>\n<div id='pbresults3' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit3\").value = \"Run program\";document.getElementById(\"inputInUse3\").value = \"N\";<\/script>\n<\/p>\n<p><code>copy.copy()<\/code>\u51fd\u6570\u4e5f\u5bf9\u5176\u4ed6\u79cd\u7c7b\u7684\u5bf9\u8c61\u9002\u7528\uff0c\u4f46\u5728\u8fd9\u91cc\u6211\u4eec\u5148\u4e0d\u8ba8\u8bba\u3002<\/p>\n<h2>\u65b9\u6cd53\uff0c\u4f7f\u7528<code>list()<\/code><\/h2>\n<p>\u6700\u540e\u4e00\u79cd\u5f97\u5230\u771f\u6b63\u526f\u672c\u7684\u65b9\u5f0f\u662f\u4f7f\u7528list()\u65b9\u7a0b\u3002\u672c\u6765\uff0c<code>list()<\/code>\u662f\u88ab\u7528\u6765\u5c06\u5176\u5b83\u7c7b\u578b\u7684\u6570\u636e\u8f6c\u5316\u6210<code>list<\/code>\u79cd\u7c7b\uff08\u6bd4\u5982\uff0c<code>list(\"hello\")<\/code> <a href=\"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/console\/?consolecode=L%20%3D%20list%28%27hello%27%29%0Aprint%28type%28L%29%29%0Aprint%28L%29%0Aprint%28L%5B0%5D%29%0Aprint%28type%28L%5B0%5D%29%29\" target=\"_blank\">\u5c06<\/a>\u5b57\u7b26\u4e32\"hello\"\u8f6c\u5316\u4e3a\u4e00\u4e2a\u6709\u4e94\u9879\u7684\u5e8f\u5217\uff0c\u6bcf\u4e00\u9879\u662f\u4e00\u4e2a\u5b57\u7b26\uff09\u3002\u4f46\u662f\u5982\u679c\u4f60\u60f3\u8981\u5c06\u4e00\u4e2a\u5e8f\u5217\u8f6c\u5316\u6210\u4e00\u4e2a\u5e8f\u5217\uff0c\u5b83\u53ea\u4f1a\u521b\u5efa\u4e00\u4e2a\u526f\u672c\u3002<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform4\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox4'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u4f7f\u7528<code>list()<\/code>\u590d\u5236<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 110px;'><textarea wrap='off' name='usercode4' id='usercode4'  cols=10 rows=4 readonly='readonly'  style = 'height : 110px;'  class='pyboxCode RO'>\noldList = [\"first\", \"second\", \"third\"]\nnewList = list(oldList)     # create a copy\noldList.reverse()\nprint(newList, oldList)<\/textarea><\/div>\n<div id='pbhistory4' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit4' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(4)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(4,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse4\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"4\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"78fd6910476b10454ad98d4378cf77b2\"\/>\n<div id='pbresults4' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit4\").value = \"Run program\";document.getElementById(\"inputInUse4\").value = \"N\";<\/script>\n<\/p>\n<h2>\u5e8f\u5217\u4f5c\u4e3a\u53c2\u6570<\/h2>\n<p>\u6ce8\u610f\uff0c\u56e0\u4e3a\u5e8f\u5217\u672c\u8eab\u8fd0\u884c\u7684\u65b9\u5f0f\uff0c\u4efb\u4f55\u5c06\u5e8f\u5217\u5f53\u4f5c\u53c2\u6570\u7684\u51fd\u6570\u90fd\u53ef\u4ee5\u6539\u53d8\u5e8f\u5217\u4e2d\u7684\u5185\u5bb9\uff08\u5728<code><a href=\"\/14-methods\/\">replace<\/a><\/code>\u7ec3\u4e60\u9898\u4e2d\u51fa\u73b0\u8fc7\uff09\u3002<\/p>\n<p><div class='pybox modeNeutral' id='pybox5'>\n<img title='You have not yet completed this problem.' src='https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-content\/plugins\/pybox\/files\/icon.png' class='pycheck'\/><div class=\"heading\"><span class='type'>Short Answer Exercise: <\/span><span class='title'>\u53c2\u6570\u5217\u8868<\/span><\/div>\u4e0b\u5217\u7a0b\u5e8f\u8f93\u51fa\u54ea\u4e2a\u6570\u5b57\uff1f<\/p>\n<pre>def func(list):\r\n \u00a0\u00a0 list[0] = list[0] + list[1]\r\n \u00a0\u00a0 list[1] = list[1] + list[0]\r\ndata = [3, 4]\r\nfunc(data)\r\nprint(data[0]*data[1])<\/pre><label for=\"pyShortAnswer5\">Your answer (enter a number): <\/label><input type=\"text\" onkeypress=\"{if (event.keyCode==13) pbShortCheck(5)}\" id=\"pyShortAnswer5\"><div class=\"pyboxbuttons\"><input type=\"hidden\" name=\"type\" value=\"number\"\/><input type=\"hidden\" name=\"correct\" value=\"77\"\/><input type=\"hidden\" name=\"slug\" value=\"17.reference\"\/><input type=\"hidden\" name=\"lang\" value=\"\"\/><input type='submit' style='margin:5px;' value='Check answer' onClick = 'pbShortCheck(5)'\/><\/div><div class=\"pbresults\" id=\"pyShortResults5\"><\/div><div class=\"epilogue\">\u6b63\u786e\uff01\u5728<code>func<\/code>\u4e2d\uff0c\u7d22\u5f150\u7684\u6570\u5b57\u53d8\u4e3a7\uff0c\u7d22\u5f151\u7684\u6570\u5b57\u53d8\u4e3a7+4=11\u3002\u6240\u4ee5\u6211\u4eec\u6253\u53707*11\u3002<\/div><\/div>\n<h2>\u4f7f\u7528<code>is<\/code>\u6bd4\u8f83\u5e8f\u5217<\/h2>\n<p>\u4ec0\u4e48\u65f6\u5019\u4e24\u4e2a\u5e8f\u5217\u53d8\u91cf<code>L1<\/code>\u548c<code>L2<\/code>\u76f8\u7b49\uff1f\u6211\u4eec\u6709\u4e24\u79cd\u65b9\u5f0f\u6765\u8f6c\u8ff0\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n<ul>\n<li><em>\u76f8\u540c\u8eab\u4efd<\/em>\uff1a<code>L1<\/code>\u548c<code>L2<\/code>\u6307\u5411\u76f8\u540c\u7684\u5e8f\u5217\u5bf9\u8c61\u4e48\uff1f<\/li>\n<li><em>\u76f8\u540c\u503c<\/em>\uff1a\u5e8f\u5217<code>L1<\/code>\u7684\u5185\u5bb9\u4e0e\u5e8f\u5217<code>L2<\/code>\u7684\u5185\u5bb9\u76f8\u540c\u4e48\uff1f<\/li>\n<\/ul>\n<p>\u5728Python\u4e2d\uff0c\u6807\u51c6\u7684\u76f8\u540c\u8fd0\u7b97\u7b26<code>==<\/code>\u610f\u5473\u7740<em>\u76f8\u540c\u7684\u503c<\/em>\uff0c\u5982\u4e0b\u6240\u793a\u3002<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform6\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox6'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div><code>==<\/code>\u7684\u542b\u4e49<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 84px;'><textarea wrap='off' name='usercode6' id='usercode6'  cols=10 rows=3 readonly='readonly'  style = 'height : 84px;'  class='pyboxCode RO'>\nL1 = ['text', 11]\nL2 = L1[:]        # make a copy\nprint(L1 == L2)   # Same Values?<\/textarea><\/div>\n<div id='pbhistory6' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit6' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(6)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(6,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse6\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"6\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"14c5779912209a08ee35289f5365c74a\"\/>\n<div id='pbresults6' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit6\").value = \"Run program\";document.getElementById(\"inputInUse6\").value = \"N\";<\/script>\n<\/p>\n<p>\u4e3a\u4e86\u6d4b\u8bd5<em>\u76f8\u540c\u8eab\u4efd<\/em>\uff0c\u6211\u4eec\u7528Python\u4e2d\u7684<code>is<\/code>\u8fd0\u7b97\u7b26\u3002\u4f7f\u7528\u8fd9\u4e2a\u8fd0\u7b97\u7b26\u7684\u65b9\u5f0f\u4e0e<code>==<\/code>\u4e00\u6837\uff1a\u53e5\u6cd5<\/p>\n<p style=\"text-align: center;\"><code>\u00ablist1\u00bb is\u00a0\u00ablist2\u00bb<\/code><\/p>\n<p>\u5982\u679c\u8fd9\u4e9b\u5e8f\u5217\u6307\u5411\u540c\u4e00\u4e2a\u5e8f\u5217\uff0c\u8fd4\u8fd8<code>True<\/code>\uff1b\u5982\u679c\u4ed6\u4eec\u6307\u5411\u4e0d\u540c\u7684\u5e8f\u5217\uff08\u5373\u4f7f\u4ed6\u4eec\u6709\u76f8\u540c\u7684\u5185\u5bb9\uff09\uff0c\u8fd4\u8fd8<code>False<\/code>\u3002<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform7\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox7'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div><code>is<\/code>\u7684\u542b\u4e49<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 162px;'><textarea wrap='off' name='usercode7' id='usercode7'  cols=10 rows=6 readonly='readonly'  style = 'height : 162px;'  class='pyboxCode RO'>\nL = ['text', 11]\nLAgain = L             # L\u7684\u53e6\u4e00\u4e2a\u5f15\u7528\nprint(LAgain is L)     # \u540c\u6837\u7684\u8eab\u4efd? \u662f\u7684\nLCopy = L[:]           # \u505a\u4e86\u4e00\u4efd\u62f7\u8d1d\nprint(LCopy == LAgain) # \u76f8\u540c\u7684\u503c?   \u662f\u7684, \u4ed6\u4eec\u90fd\u662f ['text', 11]\nprint(LCopy is LAgain) # \u540c\u6837\u7684\u8eab\u4efd? \u4e0d: LAgain \u662f L, \u4f46 LCopy \u4e0d\u662f L<\/textarea><\/div>\n<div id='pbhistory7' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit7' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(7)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(7,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse7\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"7\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"47d462db15657b7bed32264e5241893a\"\/>\n<div id='pbresults7' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit7\").value = \"Run program\";document.getElementById(\"inputInUse7\").value = \"N\";<\/script>\n<\/p>\n<p><div class='pybox modeNeutral' id='pybox8'>\n<img title='You have not yet completed this problem.' src='https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-content\/plugins\/pybox\/files\/icon.png' class='pycheck'\/><div class=\"heading\"><span class='type'>Short Answer Exercise: <\/span><span class='title'>\u771f\u6b63\u7684\u8ba1\u6570<\/span><\/div>\u8fd9\u4e2a\u7a0b\u5e8f\u7684\u8f93\u51fa\u4e2d<code>True<\/code>\u51fa\u73b0\u4e86\u591a\u5c11\u6b21\uff1f\uff08\u7ed8\u5236\u4e00\u4e2a\u56fe\u6765\u5e2e\u52a9\u8ffd\u8e2a\u6bcf\u4e00\u6b65\uff09<\/p>\n<pre>list1 = [9, 1, 1]\r\nlist3 = list(list1)\r\nlist2 = list1\r\nlist4 = list3[:]\r\nlist1[0] = 4\r\nlist5 = list1\r\nprint(list1 is list2, list2 is list3, list3 is list4, list4 is list5)\r\nprint(list1 == list2, list2 == list3, list3 == list4, list4 == list5)<\/pre><label for=\"pyShortAnswer8\">Your answer (enter a number): <\/label><input type=\"text\" onkeypress=\"{if (event.keyCode==13) pbShortCheck(8)}\" id=\"pyShortAnswer8\"><div class=\"pyboxbuttons\"><input type=\"hidden\" name=\"type\" value=\"number\"\/><input type=\"hidden\" name=\"correct\" value=\"3\"\/><input type=\"hidden\" name=\"slug\" value=\"17.is\"\/><input type=\"hidden\" name=\"lang\" value=\"\"\/><input type='submit' style='margin:5px;' value='Check answer' onClick = 'pbShortCheck(8)'\/><\/div><div class=\"pbresults\" id=\"pyShortResults8\"><\/div><div class=\"epilogue\">\u6b63\u786e\uff01\u8f93\u51fa\u662f\n<code>\nTrue False False False<\/code>\n\nTrue False True False<\/div><\/div>\n<p><table class='pywarn'><tr><td class='pywarnleft'><img src='https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-content\/plugins\/pybox\/files\/warning.png'\/><\/td><td class='pywarnright'><span> \u4f60\u4e0d\u5e94\u8be5\u5c06<code>is<\/code>\u7528\u5728\u5b57\u7b26\u4e32\u6216\u6570\u5b57\u4e2d\uff0c\u56e0\u4e3a == \u5df2\u7ecf\u6b63\u786e\u5730\u6d4b\u8bd5\u51fa\u76f8\u7b49\u6027\uff0c<code>is<\/code><a href=\"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/console\/?consolecode=%23%20%E4%B8%BA%E4%BB%80%E4%B9%88%20%22is%22%20%E5%9C%A8%E5%AD%97%E7%AC%A6%E4%B8%B2%E4%B8%AD%E5%8D%81%E5%88%86%E2%80%9C%E8%B0%83%E7%9A%AE%E2%80%9D%3F%0Aprint%28%22foo%22%20is%20%22foo%22%2C%20%22foo%22%20is%20%22fo%22%2B%22o%22%29%20%23%20%E9%83%BD%E6%98%AF%E5%AF%B9%E7%9A%84%2C%20%E7%94%B1%E4%BA%8E%E5%AD%97%E7%AC%A6%E4%B8%B2%E9%A9%BB%E7%95%99%0Aprint%28%22e%22%2A32%20is%20%22ee%22%2A16%29%20%23%20%E9%94%99%E8%AF%AF%2C%20%E9%95%BF%E5%AD%97%E7%AC%A6%E4%B8%B2%E4%B8%8D%E4%BC%9A%E8%A2%AB%E9%A9%BB%E7%95%99%0AA%20%3D%20%22foo%22%0AB%20%3D%20%22foofoo%22%0AA%20%2A%3D%202%0Aprint%28A%20%3D%3D%20B%2C%20A%20is%20B%29%20%23%20%E6%AD%A3%E7%A1%AE%20%E9%94%99%E8%AF%AF%3A%20%2A%3D%20%E4%B8%8D%E4%BC%9A%E9%87%8D%E6%96%B0%E9%A9%BB%E7%95%99%E4%B8%80%E4%B8%AA%E5%AD%97%E7%AC%A6%E4%B8%B2%0A%0A%23%20%E4%B8%BA%E4%BB%80%E4%B9%88%20%22is%22%20%E5%AF%B9%E4%BA%8E%E6%95%B0%E5%AD%97%E6%9D%A5%E8%AF%B4%E4%B9%9F%E5%8D%81%E5%88%86%E2%80%9C%E9%A1%BD%E7%9A%AE%E2%80%9D%3F%0Aprint%281%2B1%20is%202%29%20%23%20%E6%AD%A3%E7%A1%AE%2C%20%E4%BD%86%E8%BF%99%E7%A7%8D%E8%A1%A8%E7%8E%B0%E5%8F%AA%E9%92%88%E5%AF%B9%E5%B0%8F%E7%9A%84%E6%95%B4%E6%95%B0%0Aprint%2810%2A%2A3%20is%201000%29%20%23%20%E9%94%99%E8%AF%AF%0Aprint%281.5%20is%201.5%2C%201.5%20is%200.5%2A3%29%20%23%20%E6%AD%A3%E7%A1%AE%2C%20%E9%94%99%E8%AF%AF%0Aprint%28float%28%27NaN%27%29%3D%3Dfloat%28%27NaN%27%29%2C%20float%28%27NaN%27%29%20is%20float%28%27NaN%27%29%29%20%23%20%E9%83%BD%E6%98%AF%E9%94%99%E8%AF%AF%E7%9A%84%0Ax%20%3D%20float%28%27NaN%27%29%0Aprint%28x%20is%20x%2C%20x%20%3D%3D%20x%29%20%23%20%E6%AD%A3%E7%A1%AE%20%E9%94%99%E8%AF%AF%3B%20%E5%87%A0%E4%B8%AA%E4%BE%8B%E5%AD%90%E4%B9%8B%E4%B8%80%E6%9C%89%E5%85%B3%E4%BA%8E%20%27is%27T%2C%20%3D%3DF%0Aprint%280.0%20is%200%2C%200.0%20%3D%3D%200%29%20%23%20%E9%94%99%E8%AF%AF%20%E6%AD%A3%E7%A1%AE%0A%0A%23%E5%90%8C%E6%97%B6%2C%20%22is%22%20%E4%B8%8E%E6%AF%94%E8%BE%83%20id%28%29%20%E5%B9%B6%E4%B8%8D%E7%9B%B8%E5%90%8C%E3%80%82%20http%3A%2F%2Fcodepad.org%2FXb0TaKl9%0A%0A\" target=\"_blank\">\u5f88\u96be\u9884\u6d4b<\/a>\u5b57\u7b26\u4e32\u548c\u6570\u5b57\u3002 <\/span><\/td><\/table><\/p>\n<h2>\u5d4c\u5957\u5e8f\u5217<\/h2>\n<p>\u6211\u4eec\u5df2\u7ecf\u8bb2\u4e86\u5f88\u591a\uff0c\u4f46\u662f\u8fd8\u6709\u4e00\u4e2a\u503c\u5f97\u4e00\u63d0\u7684\u5e38\u89c1\u60c5\u51b5\u3002\u524d\u9762\u7684\u8bfe\u4e2d\u63d0\u5230\u8fc7\uff0c\u4e00\u4e2a<em>\u5d4c\u5957\u5e8f\u5217<\/em>\u662f\u4e00\u4e2a\u5e8f\u5217\u5d4c\u5957\u53e6\u4e00\u4e2a\u5e8f\u5217\uff0c\u6bd4\u5982<\/p>\n<p style=\"text-align: center;\"><code>sample = [365.25, [\"first\", 5]]<\/code><\/p>\n<p><code><\/code><code>sample<\/code>\u6240\u6307\u7684<em>\u5916\u9762\u7684\u5e8f\u5217<\/em>\u6709\u4e24\u9879\uff1b\u7d22\u5f15\u4e3a0\u7684\u9879\u662f\u5c0f\u6570\uff0c\u7d22\u5f15\u4e3a1\u7684\u662f<em>\u91cc\u9762\u7684\u5e8f\u5217<\/em>\u3002\u91cc\u9762\u7684\u5e8f\u5217\u662f<code>[\"first\", 5]<\/code>\uff08\u4e5f\u53ef\u4ee5\u6709\u591a\u5c42\u5d4c\u5957\uff09\u3002\u4e00\u65e6\u4f60\u5f00\u59cb\u4f7f\u7528\u5d4c\u5957\u5e8f\u5217\uff0c\u8bb0\u5f97\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n<ul>\n<li>\u5c06\u4e0a\u9762\u7684\u4e09\u4e2a\u65b9\u6cd5\u7528\u4e8e<code>sample<\/code>\u4f1a\u590d\u5236\u5916\u9762\u7684\u5e8f\u5217\uff0c\u800c\u4e0d\u4f1a\u590d\u5236\u91cc\u9762\u7684\u5e8f\u5217\u3002\u6240\u4ee5<code>copy(sample)[1] is sample[1]<\/code>\u610f\u5473\u7740\u526f\u672c\u4ecd\u6307\u5411\u539f\u5e8f\u5217\u4e2d\u7684\u4e00\u90e8\u5206\u3002\u53ef\u80fd\u8fd9\u4e0d\u662f\u4f60\u60f3\u8981\u7684\u3002\u5982\u679c\u4f60\u60f3\u5728\u5404\u4e2a\u5c42\u6b21\u4e0a\u590d\u5236\uff0c\u4f7f\u7528<code>copy.deepcopy()<\/code>\u3002<\/li>\n<li>\u4f7f\u7528<code>==<\/code>\u6d4b\u8bd5\u5d4c\u5957\u5e8f\u5217\u7ed9\u4e86\u6211\u4eec\u542f\u53d1\uff1aPython\u91cd\u590d\u5730\u5bf9\u5e8f\u5217\u5730\u6bcf\u4e00\u9879\u8c03\u7528<code>==<\/code>\u3002\u6bd4\u5982\uff0c<code>[[1, 2], 3]==[[1, 2], 3]<\/code>\u662f<code>True<\/code>\uff0c<code>[[1, 2], 3]==[1, 2, 3]<\/code>\u662f<code>False<\/code>\uff0c\u56e0\u4e3a\u524d\u51e0\u9879\u662f\u4e0d\u4e00\u6837\u7684\uff08<code>[1, 2] != 1<\/code>\uff09\u3002<\/li>\n<\/ul>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform9\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox9'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div><code>deepcopy<\/code> and recursive equality<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 266px;'><textarea wrap='off' name='usercode9' id='usercode9'  cols=10 rows=10 readonly='readonly'  style = 'height : 266px;'  class='pyboxCode RO'>\nimport copy\nsample = [365.25, [\"first\", 5]]\nclone = copy.copy(sample)\nprint(sample, clone)\nprint(sample == clone, sample is clone)\nprint(sample[1] == clone[1], sample[1] is clone[1])\ndeepclone = copy.deepcopy(sample)\nprint(deepclone)\nprint(sample == deepclone, sample is deepclone)\nprint(sample[1] == deepclone[1], sample[1] is deepclone[1])<\/textarea><\/div>\n<div id='pbhistory9' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit9' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(9)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(9,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse9\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"9\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"9e283f578fffcb8094b88d7e64992baa\"\/>\n<div id='pbresults9' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit9\").value = \"Run program\";document.getElementById(\"inputInUse9\").value = \"N\";<\/script>\n<\/p>\n<p>\u8fd9\u8282\u8bfe\u7684\u5185\u5bb9\u5230\u6b64\u7ed3\u675f\uff01\u4e0b\u9762\u7684\u5185\u5bb9\u4e3a\u9009\u5b66\u3002<\/p>\n<hr \/>\n<h2>\u6570\u7ec4\uff08\u5143\u7ec4\uff09\uff1a<code>(\"immutable\", \"lists\")<\/code><\/h2>\n<p>\u5728\u4e0a\u9762\u63d0\u5230\u8fc7\uff0c\u5bf9\u4e00\u4e2a\u5e8f\u5217\u8c03\u7528\u4e00\u4e2a\u65b9\u7a0b\u53ef\u4ee5\u6539\u53d8\u5e8f\u5217\u3002\u6709\u65f6\u6211\u4eec\u5e76\u4e0d\u60f3\u8ba9\u8fd9\u79cd\u60c5\u51b5\u53d1\u751f\uff01Python\u4e2d\u7684\u4e00\u79cd\u89e3\u51b3\u65b9\u5f0f\u662f\u521b\u5efa<em>\u6570\u7ec4<\/em>\u3002\u6570\u7ec4\u672c\u8d28\u548c\u5e8f\u5217\u4e00\u6837\uff0c\u4f46\u662f\u4e0d\u53ef\u4ee5\u88ab\u6539\u52a8\u3002\u6211\u4eec\u8bf4\u5e8f\u5217\u662f<em>\"\u53ef\u6539\u52a8\u7684\"<\/em>\uff0c\u6570\u7ec4\u662f<em>\"\u4e0d\u53ef\u6539\u52a8\u7684\"<\/em>\uff08\u5b57\u7b26\u4e32\u548c\u6570\u5b57\u4e5f\u662f\u4e0d\u53ef\u6539\u52a8\u7684\uff09\u3002\u8fd9\u53ef\u4ee5\u7528\u6765\u9884\u9632\u4efb\u4f55\u7f16\u7a0b\u9519\u8bef\uff0c\u5305\u62ec\u8bef\u6539\u5e8f\u5217\u3002\u6570\u7ec4\u4f7f\u7528\u5c0f\u62ec\u53f7<code>()<\/code>\u800c\u4e0d\u662f\u4e2d\u62ec\u53f7<code>[]<\/code>\u3002\u6570\u7ec4\u548c\u5e8f\u5217\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528<code>tuple()<\/code>\u548c<code>list()<\/code>\u76f8\u4e92\u8f6c\u6362\u3002<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform10\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox10'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u7ba1\u72b6\u6570\u7ec4\uff08\u5143\u7ec4\uff09<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 188px;'><textarea wrap='off' name='usercode10' id='usercode10'  cols=10 rows=7 readonly='readonly'  style = 'height : 188px;'  class='pyboxCode RO'>\nT = (3, 4, 5)\nprint(T)\nprint(type(T))           # \u5143\u7ec4\nprint(T[0])              # \u5143\u7ec4\u4e2d\u7684\u7b2c\u4e00\u9879\nprint(list(T))           # \u5c06\u4e00\u4e2a\u5143\u7ec4\u8f6c\u6362\u4e3a\u4e00\u4e2a\u5217\u8868\nprint(tuple([1, 2, 3]))  # \u5c06\u4e00\u4e2a\u5217\u8868\u8f6c\u6362\u4e3a\u4e00\u4e2a\u5143\u7ec4\nT[0] = \"three\"           # \u9519\u8bef! \u4f60\u65e0\u6cd5\u6539\u53d8\u5143\u7ec4\u503c<\/textarea><\/div>\n<div id='pbhistory10' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit10' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(10)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(10,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse10\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"10\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"428cdeeda6b2d1e3467ac0d5565637d5\"\/>\n<div id='pbresults10' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit10\").value = \"Run program\";document.getElementById(\"inputInUse10\").value = \"N\";<\/script>\n<\/p>\n<h2>To <code>\u221e<\/code> and Beyond\uff1a\u4e0d\u5408\u7fa4<\/h2>\n<p>\u521b\u5efa\u4e00\u4e2a\u5305\u542b\u81ea\u8eab\u7684\u5e8f\u5217\u662f\u53ef\u80fd\u7684\uff01\u53ea\u9700\u521b\u5efa\u4e00\u4e2a\u5e8f\u5217\uff0c\u7136\u540e\u5c06\u5176\u4e2d\u7684\u4e00\u9879\u91cd\u65b0\u6307\u56de\u6574\u4e2a\u7684\u5e8f\u5217\uff1a<\/p>\n<p><form class=\"pbform\" action=\"#\" id=\"pbform11\" method=\"POST\">\n<div class='pybox modeNeutral  facultative' id='pybox11'>\n<div class=\"heading\"><span class=\"title\">Example<\/span><\/div>\u5faa\u73af\u5f15\u7528<div class='pyboxTextwrap pyboxCodewrap RO '  style='height: 136px;'><textarea wrap='off' name='usercode11' id='usercode11'  cols=10 rows=5 readonly='readonly'  style = 'height : 136px;'  class='pyboxCode RO'>\nL = [\"zero\", \"one\"]\nL[1] = L\nprint(len(L))\nprint(L)\nprint(L is L[1])<\/textarea><\/div>\n<div id='pbhistory11' class='flexcontain' style='display:none;'><\/div>\n<div class='pyboxbuttons'><table><tr>\n<td><input type='submit' name='submit' id='submit11' value=' '\/><\/td>\n<td><input type='button' name='consolecopy' value=\"Open in console\" onclick=\"pbConsoleCopy(11)\" ><\/td>\n<td><input type='button' name='visualize' value=\"Visualize\" onclick=\"pbVisualize(11,'N')\" ><\/td>\n<\/tr><\/table><\/div>\n<input type=\"hidden\" name=\"lang\" value=\"\"\/><input type=\"hidden\" id=\"inputInUse11\" name=\"inputInUse\" value=\"Y\"\/>\n<input type=\"hidden\" name=\"pyId\" value=\"11\"\/>\n<input type=\"hidden\" name=\"hash\" value=\"ef2417b9b7c2f2b395ad4f54e60f4005\"\/>\n<div id='pbresults11' class='pbresults'><\/div>\n<\/div>\n<\/form>\n<script type='text\/javascript'>document.getElementById(\"submit11\").value = \"Run program\";document.getElementById(\"inputInUse11\").value = \"N\";<\/script>\n<\/p>\n<p>\u6ce8\u610fPython\u7684\u8f93\u51fa\u5f15\u64ce\u80fd\u591f\u8bc6\u522b\u5e8f\u5217\u81ea\u8eab\u5faa\u73af: \u5b83\u6253\u5370\u51fa\"<code>...<\/code>\"\uff0c\u800c\u4e0d\u662f\u91cd\u590d\u6253\u5370\u6240\u6709\u7684<code>L<\/code>\uff0c\u4ee5\u6b64\u907f\u514d\u65e0\u9650\u5faa\u73af\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u8fd9\u8282\u8bfe\u63d0\u4f9b\u66f4\u591a\u6709\u5173Python\u50a8\u5b58\u5e8f\u5217\u7684\u4fe1\u606f\u3002\u590d\u5236\u5e76\u6bd4\u8f83\u5e8f\u5217\u4f1a\u6709\u9884\u6599\u4e4b\u5916\u7684\u7ed3\u679c\u3002\u6211\u4eec\u4f1a\u89e3\u91caPython\u5185\u90e8\u662f\u5982\u4f55\u8fd0\u884c\u7684\uff0c\u8ba9\u4f60\u7406\u89e3\u5e76\u907f\u514d\u8fd9\u4e9b\u9519\u8bef\u3002\u6bd4\u5982\uff0c\u4e00\u4e2a\u666e\u904d\u7684\u95ee\u9898\u662f\u51e0\u4e2a\u4e0d\u540c\u7684\u53d8\u91cf\u4f1a\u201c\u8868\u660e\u201d\u6216\u201c\u6307\u5411\u201d\u76f8\u540c\u7684\u5e8f\u5217\u3002\u8fd9\u8282\u8bfe\u7684\u672b\u5c3e\u6211\u4eec\u4f1a\u5f15\u5165\"is\"\u8fd0\u7b97\u7b26\u3002\u8fd9\u4e2a\u8fd0\u7b97\u7b26\u662f\u7528\u6765\u5224\u65ad\u662f\u5426\u591a\u4e2a\u53d8\u91cf\u786e\u5b9e\u6307\u5411\u540c\u4e00\u4e2a\u5e8f\u5217\u3002 \u8303\u4f8b \u6211\u4eec\u60f3\u8981\u4e00\u4e32\u4ee3\u7801\uff0c\u5c06\u4e00\u4e2a\u82f1\u5c3a\u4e3a\u5355\u4f4d\u7684\u957f\u5ea6\u5e8f\u5217oldSize\u8f6c\u53d8\u4e3a\u4e00\u4e2a\u4ee5\u5398\u7c73\u4e3a\u5355\u4f4d\u7684\u957f\u5ea6\u5e8f\u5217newSize\u3002\u5176\u4e2d\u4e00\u79cd\u65b9\u5f0f\u662f\u4f7f\u7528newSize = oldSize\u6765\u5efa\u7acb\u4e00\u4efd\u526f\u672c\uff0c\u7136\u540e\u63a5\u7740\u5f80\u4e0b\u6539\u53d8\u6240\u6709\u7684\u503c\uff1a oldSize = [\"letter\", 8.5, 11] \u00a0 # size of paper in inches newSize =\u00a0oldSize \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 # make a copy? newSize[1] = newSize[1]*2.54 \u00a0 \u00a0# convert to cm newSize[2] = &hellip; <a href=\"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/zh-17\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-9307","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/pages\/9307","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/comments?post=9307"}],"version-history":[{"count":16,"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/pages\/9307\/revisions"}],"predecessor-version":[{"id":10241,"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/pages\/9307\/revisions\/10241"}],"wp:attachment":[{"href":"https:\/\/cscircles.cemc.uwaterloo.ca\/dev\/wp-json\/wp\/v2\/media?parent=9307"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}