{"id":3026,"date":"2025-05-28T16:20:17","date_gmt":"2025-06-04T09:07:16","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=3026"},"modified":"2025-06-04T16:20:17","modified_gmt":"2025-06-04T09:07:16","slug":"%e4%ba%86%e8%a7%a3python%e4%b8%adlen%e5%87%bd%e6%95%b8%e7%9a%84%e5%8a%9f%e8%83%bd","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/python\/%e4%ba%86%e8%a7%a3python%e4%b8%adlen%e5%87%bd%e6%95%b8%e7%9a%84%e5%8a%9f%e8%83%bd\/","title":{"rendered":"\u5168\u9762\u4e86\u89e3 Python \u7684 len() \u51fd\u6578\uff1a\u6700\u4f73\u5be6\u8e10\u8207\u61c9\u7528\u793a\u4f8b\uff082025 \u66f4\u65b0\uff09"},"content":{"rendered":"

<\/p>\n

Python \u7684 `len()` \u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u4e14\u5be6\u7528\u7684\u5167\u5efa\u51fd\u6578\uff0c\u5b83\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u5b57\u4e32\u3001\u5217\u8868\u3001\u5143\u7d44\u3001\u5b57\u5178\u7b49\u5404\u985e\u7269\u4ef6\u7684\u9577\u5ea6\u3002\u9019\u500b\u51fd\u6578\u70ba\u6211\u5011\u63d0\u4f9b\u4e86\u4e00\u500b\u7c21\u55ae\u7684\u65b9\u6cd5\u4f86\u5feb\u901f\u7372\u53d6\u7269\u4ef6\u7684\u5927\u5c0f\uff0c\u800c\u7121\u9700\u4f9d\u8cf4\u7e41\u7463\u7684\u8a08\u7b97\u904e\u7a0b\u3002<\/p>\n

len() \u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5<\/h2>\n

\u4f7f\u7528 `len()` \u51fd\u6578\u7684\u65b9\u6cd5\u975e\u5e38\u7c21\u55ae\u3002\u53ea\u9700\u5c07\u76ee\u6a19\u7269\u4ef6\u4f5c\u70ba\u53c3\u6578\u50b3\u5165 `len()` \u51fd\u6578\uff0c\u5373\u53ef\u7372\u5f97\u8a72\u7269\u4ef6\u7684\u9577\u5ea6\u3002\u4ee5\u4e0b\u662f\u8a08\u7b97\u5b57\u4e32\u9577\u5ea6\u7684\u7bc4\u4f8b\uff1a<\/p>\n

“`python
\nmy_string = “Hello World!”
\nlength = len(my_string)
\nprint(length) # \u8f38\u51fa\uff1a12
\n“`<\/p>\n

\u5728\u9019\u6bb5\u7a0b\u5f0f\u78bc\u4e2d\uff0c\u6211\u5011\u8a08\u7b97\u4e86\u8b8a\u6578 `my_string` \u7684\u9577\u5ea6\uff0c\u7d50\u679c\u70ba 12\uff0c\u9019\u662f\u56e0\u70ba\u5b57\u4e32\u4e2d\u5305\u542b\u4e86 12 \u500b\u5b57\u7b26\uff08\u5305\u62ec\u7a7a\u683c\uff09\u3002<\/p>\n

len() \u51fd\u6578\u7684\u512a\u9ede<\/h2>\n

`len()` \u51fd\u6578\u7684\u4e3b\u8981\u512a\u9ede\u662f\u80fd\u5920\u5feb\u901f\u5730\u8a08\u7b97\u7269\u4ef6\u7684\u9577\u5ea6\uff0c\u800c\u7121\u9700\u624b\u52d5\u8a08\u7b97\uff0c\u9019\u5c0d\u65bc\u8655\u7406\u5927\u91cf\u8cc7\u6599\u6642\u7279\u5225\u6709\u7528\u3002\u6b64\u5916\uff0c\u5b83\u9084\u53ef\u4ee5\u7528\u4f86\u6aa2\u67e5\u7269\u4ef6\u662f\u5426\u70ba\u7a7a\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u7684\u7a0b\u5f0f\u78bc\u5c55\u793a\u4e86\u5982\u4f55\u6aa2\u67e5\u4e00\u500b\u5217\u8868\u662f\u5426\u70ba\u7a7a\uff1a<\/p>\n

“`python
\nmy_list = []\nif len(my_list) == 0:
\n print(“The list is empty”) # \u8f38\u51fa\uff1aThe list is empty
\n“`<\/p>\n

\u9019\u6bb5\u7a0b\u5f0f\u78bc\u4f7f\u7528 `len()` \u51fd\u6578\u4f86\u8a55\u4f30 `my_list` \u7684\u9577\u5ea6\uff0c\u82e5\u8fd4\u56de\u503c\u70ba 0\uff0c\u5247\u8868\u793a\u5217\u8868\u662f\u7a7a\u7684\u3002<\/p>\n

\u932f\u8aa4\u6392\u9664<\/h2>\n

\u5728\u4f7f\u7528 `len()` \u51fd\u6578\u6642\uff0c\u60a8\u53ef\u80fd\u6703\u9047\u5230\u4e00\u4e9b\u5e38\u898b\u7684\u932f\u8aa4\uff0c\u5982\u4e0b\uff1a<\/p>\n

1. **TypeError**: \u8a66\u5716\u8a08\u7b97\u975e\u53ef\u8a08\u7b97\u9577\u5ea6\u7684\u7269\u4ef6\uff08\u5982 `None`\uff09\u3002\u78ba\u4fdd\u60a8\u50b3\u5165\u7684\u53c3\u6578\u662f\u5b57\u4e32\u3001\u5217\u8868\u3001\u5143\u7d44\u6216\u5b57\u5178\u7b49\u3002<\/p>\n

“`python
\n my_variable = None
\n print(len(my_variable)) # \u9019\u6703\u5c0e\u81f4 TypeError
\n “`<\/p>\n

2. **IndexError**: \u4f7f\u7528 `len()` \u51fd\u6578\u5f8c\uff0c\u8acb\u5c0f\u5fc3\u5728\u5f8c\u7e8c\u64cd\u4f5c\u4e2d\u4f7f\u7528\u7d22\u5f15\uff0c\u78ba\u4fdd\u4e0d\u6703\u8d85\u51fa\u7bc4\u570d\u3002<\/p>\n

\u5ef6\u4f38\u61c9\u7528<\/h2>\n

\u9664\u4e86\u57fa\u672c\u7684\u9577\u5ea6\u6aa2\u67e5\uff0c`len()` \u51fd\u6578\u9084\u53ef\u4ee5\u914d\u5408\u5176\u4ed6 Python \u529f\u80fd\u9032\u884c\u66f4\u8907\u96dc\u7684\u64cd\u4f5c\u3002\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 `len()` \u4f86\u9032\u884c\u8cc7\u6599\u9a57\u8b49\u6216\u6e05\u7406\uff0c\u78ba\u4fdd\u8f38\u5165\u7684\u8cc7\u6599\u7b26\u5408\u7279\u5b9a\u7684\u9577\u5ea6\u8981\u6c42\u3002<\/p>\n

“`python
\ndef validate_username(username):
\n if len(username) < 5:\n return \"Username must be at least 5 characters long.\"\n return \"Username is valid.\"\n```\n\n\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u5275\u5efa\u4e86\u4e00\u500b\u51fd\u6578\u4f86\u9a57\u8b49\u7528\u6236\u540d\u7684\u9577\u5ea6\uff0c\u4ee5\u78ba\u4fdd\u5176\u7b26\u5408\u8981\u6c42\u3002\n\n\n\n

\u7e3d\u7d50<\/h2>\n

`len()` \u51fd\u6578\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684 Python \u51fd\u6578\uff0c\u5b83\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u5b57\u4e32\u3001\u5217\u8868\u3001\u5143\u7d44\u3001\u5b57\u5178\u7b49\u7269\u4ef6\u7684\u9577\u5ea6\uff0c\u4e5f\u53ef\u4ee5\u7528\u4f86\u6aa2\u67e5\u7269\u4ef6\u662f\u5426\u70ba\u7a7a\u3002\u5176\u6700\u5927\u512a\u9ede\u662f\u80fd\u5feb\u901f\u8a08\u7b97\u7269\u4ef6\u7684\u9577\u5ea6\uff0c\u9019\u5c0d\u65bc\u8655\u7406\u5927\u91cf\u8cc7\u6599\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u82e5\u60a8\u60f3\u4e86\u89e3\u66f4\u591a Python \u7684\u76f8\u95dc\u6559\u5b78\uff0c\u8acb\u53c3\u8003 [\u9019\u88e1](https:\/\/vocus.cc) \u4ee5\u7372\u53d6\u6df1\u5165\u7684\u5167\u5bb9\u548c\u7bc4\u4f8b\u3002<\/p>\n

Q&A\uff08\u5e38\u898b\u554f\u984c\u89e3\u7b54\uff09<\/h2>\n

**1. len() \u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u54ea\u4e9b\u985e\u578b\u7684\u7269\u4ef6\u7684\u9577\u5ea6\uff1f**
\n`len()` \u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u5b57\u4e32\u3001\u5217\u8868\u3001\u5143\u7d44\u3001\u5b57\u5178\u3001\u96c6\u5408\u7b49\u7269\u4ef6\u7684\u9577\u5ea6\u3002<\/p>\n

**2. \u5982\u679c\u6211\u50b3\u5165\u4e00\u500b\u7121\u6cd5\u8a08\u7b97\u9577\u5ea6\u7684\u7269\u4ef6\uff0c\u6703\u767c\u751f\u4ec0\u9ebc\u4e8b\uff1f**
\n\u5982\u679c\u60a8\u50b3\u5165\u4e00\u500b\u7121\u6cd5\u8a08\u7b97\u9577\u5ea6\u7684\u7269\u4ef6\uff08\u4f8b\u5982 `None`\uff09\uff0cPython \u5c07\u6703\u5f15\u767c `TypeError`\u3002<\/p>\n

**3. len() \u51fd\u6578\u7684\u8fd4\u56de\u503c\u662f\u4ec0\u9ebc\u985e\u578b\uff1f**
\n`len()` \u51fd\u6578\u7684\u8fd4\u56de\u503c\u662f\u6574\u6578\u985e\u578b\uff0c\u8868\u793a\u7269\u4ef6\u7684\u5143\u7d20\u6578\u91cf\u6216\u9577\u5ea6\u3002<\/p>\n

—<\/p>\n","protected":false},"excerpt":{"rendered":"

Python\u4e2dlen()\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u5b57\u4e32\u3001\u5217\u8868\u3001\u5b57\u5178\u3001\u96c6\u5408\u7b49\u7269\u4ef6\u7684\u9577\u5ea6\uff0c\u672c\u6587\u5c07\u4ecb\u7d39len()\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5\uff0c\u4ee5\u53ca\u5b83\u7684\u512a\u9ede\u548c\u7f3a\u9ede\u3002<\/p>\n","protected":false},"author":1,"featured_media":2518,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[18],"tags":[15],"class_list":["post-3026","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-python","tag-python"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2022\/12\/DALL\u00b7E-2022-12-28-14.25.55-\u62f7\u8c9d2.png","jetpack-related-posts":[],"jetpack_shortlink":"https:\/\/wp.me\/pcFK27-MO","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3026","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/comments?post=3026"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3026\/revisions"}],"predecessor-version":[{"id":3027,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3026\/revisions\/3027"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media\/2518"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=3026"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=3026"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=3026"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}