{"id":17,"date":"2007-08-27T22:29:49","date_gmt":"2007-08-27T14:29:49","guid":{"rendered":"http:\/\/blog.orczhou.com\/?p=17"},"modified":"2025-11-09T18:12:07","modified_gmt":"2025-11-09T10:12:07","slug":"strlen-mb_strlen","status":"publish","type":"post","link":"https:\/\/www.orczhou.com\/index.php\/2007\/08\/strlen-mb_strlen\/","title":{"rendered":"strlen\u3001mb_strlen\u8ba1\u7b97\u4e2d\u82f1\u6587\u6df7\u6392\u5b57\u7b26\u4e32\u957f\u5ea6"},"content":{"rendered":"\n

\u5728php\u4e2d\u5e38\u89c1\u7684\u8ba1\u7b97\u5b57\u7b26\u4e32\u957f\u5ea6\u7684\u51fd\u6570\u6709\uff1astrlen\u548cmb_strlen\uff0c\u4e0b\u9762\u662f\u5bf9\u8fd9\u4e24\u4e2a\u51fd\u6570\u7684\u6bd4\u8f83\u8bf4\u660e\uff08\u7f16\u7801\u65b9\u5f0fUTF8\uff09<\/p>\n\n\n\n

\u6bd4\u8f83strlen\u548cmb_strlen<\/h4>\n\n\n\n

\u5f53\u5b57\u7b26\u5168\u662f\u82f1\u6587\u5b57\u7b26\u7684\u65f6\u5019\uff0c\u4e24\u8005\u662f\u4e00\u6837\u3002\u8fd9\u91cc\u4e3b\u8981\u6bd4\u8f83\u4e00\u4e0b\uff0c\u4e2d\u82f1\u6587\u6df7\u6392\u7684\u65f6\u5019\uff0c\u4e24\u4e2a\u8ba1\u7b97\u7ed3\u679c\u3002\uff08\u6d4b\u8bd5\u65f6\u7f16\u7801\u65b9\u5f0f\u662fUTF8\uff09<\/p>\n\n\n\n

$str='\u4e2d\u6587a\u5b571\u7b26';\necho strlen($str);\necho '';\necho mb_strlen($str,'UTF8');\n\/\/\u8f93\u51fa\u7ed3\u679c\n\/\/14\n\/\/6<\/code><\/pre>\n\n\n\n
\u7ed3\u679c\u5206\u6790\uff1a\u5728strlen\u8ba1\u7b97\u65f6\uff0c\u5bf9\u5f85\u4e00\u4e2aUTF8\u7684\u4e2d\u6587\u5b57\u7b26\u662f3\u4e2a\u957f\u5ea6\uff0c\u6240\u4ee5\u201c\u4e2d\u6587a\u5b571\u7b26\u201d\u957f\u5ea6\u662f 3*4+2=14\u3002<\/p>\n\n\n\n
\u5728mb_strlen\u8ba1\u7b97\u65f6\uff0c\u9009\u5b9a\u5185\u7801\u4e3aUTF8\uff0c\u5219\u4f1a\u5c06\u4e00\u4e2a\u4e2d\u6587\u5b57\u7b26\u5f53\u4f5c\u957f\u5ea61\u6765\u8ba1\u7b97\uff0c\u6240\u4ee5\u201c\u4e2d\u6587a\u5b571\u7b26\u201d\u957f\u5ea6\u662f6\u3002<\/p>\n\n\n\n
\u5173\u4e8e\u4e2d\u82f1\u6587\u6df7\u6392\u4e32\u7684\u5360\u4f4d\u7b26\u8ba1\u7b97<\/h4>\n\n\n\n
\u5229\u7528\u8fd9\u4e24\u4e2a\u51fd\u6570\u5219\u53ef\u4ee5\u8054\u5408\u8ba1\u7b97\u51fa\u4e00\u4e2a\u4e2d\u82f1\u6587\u6df7\u6392\u7684\u4e32\u7684\u5360\u4f4d\u662f\u591a\u5c11\uff08\u4e00\u4e2a\u4e2d\u6587\u5b57\u7b26\u7684\u5360\u4f4d\u662f2\uff0c\u82f1\u6587\u5b57\u7b26\u662f1\uff09\uff0c\u8ba1\u7b97\u7684\u65b9\u6cd5\u662f\uff1a\u5982\u679c\u4e00\u4e2a\u6df7\u6392\u5b57\u7b26\u4e32\u6709a\u4e2a\u4e2d\u6587\uff0cb\u4e2a\u82f1\u6587\uff0c\u5360\u4f4d\u662f:<\/p>\n\n\n\n
$str='\u4e2d\u6587a\u5b571\u7b26';\n\/\/\u8ba1\u7b97\u5982\u4e0b\necho ( strlen($str) + mb_strlen($str,'UTF8') ) \/ 2;\n\/\/\u8f93\u51fa\u7ed3\u679c\n\/\/10<\/pre><\/code><\/pre>\n\n\n\n
\u4f8b\u5982\u00a0 \u201c\u4e2d\u6587a\u5b571\u7b26\u201d \u7684strlen($str)\u503c\u662f14\uff0cmb_strlen($str)\u503c\u662f6\uff0c\u5219\u53ef\u4ee5\u8ba1\u7b97\u51fa\u201c\u4e2d\u6587a\u5b571\u7b26\u201d\u7684\u5360\u4f4d\u662f 10 \u3002<\/p>\n\n\n\n
\u6700\u5927\u5360\u4f4d\u8ba1\u7b97<\/h4>\n\n\n\n
\u4e00\u822c\u7684\u82f1\u6587\u5b57\u7b26\u5360\u4f4d\u8981\u6bd4\u4e2d\u6587\u5c0f\u4e00\u4e9b\uff0c\u4f8b\u5982\uff0c\u53ef\u80fd\u4e24\u4e2a\u82f1\u6587\u5b57\u7b26\u7684\u5bbd\u5ea6\u624d\u662f\u4e00\u4e2a\u4e2d\u6587\u5b57\u7b26\u7684\u5bbd\u5ea6\uff0c\u6240\u4ee5\uff0c\u5f53\u6211\u4eec\u5141\u8bb8 max \u4e2a\u4e2d\u6587\u5b57\u7b26\u5bbd\u5ea6\u7684\u65f6\u5019\uff0c\u53ef\u4ee5\u4f7f\u7528\u7c7b\u4f3c\u5165\u5982\u4e0b\u7684\u8ba1\u7b97\uff0c\u8ba1\u7b97\u603b\u5bbd\u5ea6\uff1a<\/p>\n\n\n\n\n\n
$$
\n3*x + y = \\text{strlen} \\\\
\nx + y = \\text{mb_strlen} \\\\
\n2x =  \\text{strlen} –  \\text{mb_strlen} \\\\
\nx  =  \\frac{\\text{strlen} –  \\text{mb_strlen}}{2} \\\\
\nz*\\frac{x}{x+y}*2 + z*\\frac{y}{x+y} \\le MAX  \\\\
\nz \\le \\frac{MAX*(x+y)}{(2x+y)} = \\frac{MAX*(\\text{mb_strlen})}{(2x+y)} = \\frac{MAX*(\\text{mb_strlen})}{( \\frac{\\text{strlen} + \\text{mb_strlen}}{2} )} \\\\
\n = \\frac{2*MAX*(\\text{mb_strlen})}{( \\text{strlen} + \\text{mb_strlen} )}  \\\\
\n$$<\/p>\n","protected":false},"excerpt":{"rendered":"
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