{"id":158,"title":"php\u6570\u636e\u7c7b\u578b","good":0,"bad":0,"hit":2891,"created_at":"2016-01-12 21:01:42","content":"<p>PHP \u652f\u6301 8 \u79cd\u539f\u59cb\u6570\u636e\u7c7b\u578b\u3002<\/p><p>\u56db\u79cd\u6807\u91cf\u7c7b\u578b\uff1a<\/p><p><br\/><\/p><ul class=\" list-paddingleft-2\"><li><p><span id=\"_baidu_bookmark_start_1\" style=\"display: none; line-height: 0px;\">\u200d<\/span>boolean\uff08\u5e03\u5c14\u578b\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>integer\uff08\u6574\u578b\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>float\uff08\u6d6e\u70b9\u578b\uff0c\u4e5f\u79f0\u4f5c double) &nbsp; &nbsp;<\/p><\/li><li><p>string\uff08\u5b57\u7b26\u4e32\uff09<span id=\"_baidu_bookmark_end_2\" style=\"display: none; line-height: 0px;\">\u200d<\/span> &nbsp; &nbsp;<\/p><\/li><\/ul><p><br\/><\/p><p>\u4e24\u79cd\u590d\u5408\u7c7b\u578b\uff1a<\/p><p><br\/><\/p><ul class=\" list-paddingleft-2\"><li><p>array\uff08\u6570\u7ec4\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>object\uff08\u5bf9\u8c61\uff09 &nbsp; &nbsp;<\/p><\/li><\/ul><p><br\/><\/p><p>\u6700\u540e\u662f\u4e24\u79cd\u7279\u6b8a\u7c7b\u578b\uff1a<\/p><p><br\/><\/p><ul class=\" list-paddingleft-2\"><li><p>resource\uff08\u8d44\u6e90\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>NULL\uff08\u65e0\u7c7b\u578b\uff09 &nbsp; &nbsp;<\/p><\/li><\/ul><p><br\/><\/p><p>\u4e3a\u4e86\u786e\u4fdd\u4ee3\u7801\u7684\u6613\u8bfb\u6027\uff0c\u672c\u624b\u518c\u8fd8\u4ecb\u7ecd\u4e86\u4e00\u4e9b\u4f2a\u7c7b\u578b\uff1a<\/p><p><br\/><\/p><ul class=\" list-paddingleft-2\"><li><p>mixed\uff08\u6df7\u5408\u7c7b\u578b\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>number\uff08\u6570\u5b57\u7c7b\u578b\uff09 &nbsp; &nbsp;<\/p><\/li><li><p>callback\uff08\u56de\u8c03\u7c7b\u578b\uff09 &nbsp; <br\/><\/p><\/li><li><p><br\/><\/p><\/li><li><p><strong>1\u3001 boolean\u578b<\/strong><\/p><\/li><li><p>\u5f53\u8f6c\u6362\u4e3a boolean \u65f6\uff0c\u4ee5\u4e0b\u503c\u88ab\u8ba4\u4e3a\u662f FALSE\uff1a<\/p><\/li><li><p><br\/><\/p><\/li><li><p>\u5e03\u5c14\u503c FALSE \u672c\u8eab &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>\u6574\u578b\u503c 0\uff08\u96f6\uff09 &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>\u6d6e\u70b9\u578b\u503c 0.0\uff08\u96f6\uff09 &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>&nbsp; &nbsp; \u7a7a\u5b57\u7b26\u4e32\uff0c\u4ee5\u53ca\u5b57\u7b26\u4e32 &quot;0&quot; &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>\u4e0d\u5305\u62ec\u4efb\u4f55\u5143\u7d20\u7684\u6570\u7ec4 &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>&nbsp; &nbsp; \u4e0d\u5305\u62ec\u4efb\u4f55\u6210\u5458\u53d8\u91cf\u7684\u5bf9\u8c61\uff08\u4ec5 PHP 4.0 \u9002\u7528\uff09 &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>&nbsp; &nbsp; \u7279\u6b8a\u7c7b\u578b NULL\uff08\u5305\u62ec\u5c1a\u672a\u8d4b\u503c\u7684\u53d8\u91cf\uff09 &nbsp; &nbsp;<\/p><\/li><li><p><br\/><\/p><\/li><li><p>&nbsp; &nbsp; \u4ece\u7a7a\u6807\u8bb0\u751f\u6210\u7684 SimpleXML \u5bf9\u8c61 &nbsp; &nbsp;<\/p><\/li><li><p>\u6240\u6709\u5176\u5b83\u503c\u90fd\u88ab\u8ba4\u4e3a\u662f TRUE\uff08\u5305\u62ec\u4efb\u4f55\u8d44\u6e90\uff09\u3002<\/p><\/li><li><p>Warning &nbsp; &nbsp;<\/p><\/li><li><p>-1 \u548c\u5176\u5b83\u975e\u96f6\u503c\uff08\u4e0d\u8bba\u6b63\u8d1f\uff09\u4e00\u6837\uff0c\u88ab\u8ba4\u4e3a\u662f TRUE\uff01<\/p><\/li><li><p>&lt;?php<br\/>var_dump((bool)&nbsp;&quot;&quot;);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(false)<br\/>var_dump((bool)&nbsp;1);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(true)<br\/>var_dump((bool)&nbsp;-2);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(true)<br\/>var_dump((bool)&nbsp;&quot;foo&quot;);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(true)<br\/>var_dump((bool)&nbsp;2.3e5);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(true)<br\/>var_dump((bool)&nbsp;array(12));&nbsp;\/\/&nbsp;bool(true)<br\/>var_dump((bool)&nbsp;array());&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(false)<br\/>var_dump((bool)&nbsp;&quot;false&quot;);&nbsp;&nbsp;&nbsp;\/\/&nbsp;bool(true)<br\/>?&gt;<\/p><\/li><li><p><br\/><\/p><\/li><\/ul><p><br\/><\/p><p><strong>2\u3001\u6574\u578b<\/strong><br\/><\/p><p class=\"title\">Integer \u6574\u578b<\/p><p>\u4e00\u4e2a integer \u662f\u96c6\u5408 ? = {..., -2, -1, 0, 1, 2, ...} \u4e2d\u7684\u4e00\u4e2a\u6570\u3002<\/p><p class=\"title\">\u8bed\u6cd5<\/p><p>\u6574\u578b\u503c\u53ef\u4ee5\u4f7f\u7528\u5341\u8fdb\u5236\uff0c\u5341\u516d\u8fdb\u5236\uff0c\u516b\u8fdb\u5236\u6216\u4e8c\u8fdb\u5236\u8868\u793a\uff0c\u524d\u9762\u53ef\u4ee5\u52a0\u4e0a\u53ef\u9009\u7684\u7b26\u53f7\uff08- \u6216\u8005 +\uff09\u3002<\/p><p>Example #1 \u6574\u6570\u6587\u5b57\u8868\u8fbe<\/p><p>&lt;?php<br\/>$a&nbsp;=&nbsp;1234;&nbsp;\/\/&nbsp;\u5341\u8fdb\u5236\u6570<br\/>$a&nbsp;=&nbsp;-123;&nbsp;\/\/&nbsp;\u8d1f\u6570<br\/>$a&nbsp;=&nbsp;0123;&nbsp;\/\/&nbsp;\u516b\u8fdb\u5236\u6570&nbsp;(\u7b49\u4e8e\u5341\u8fdb\u5236&nbsp;83)<br\/>$a&nbsp;=&nbsp;0x1A;&nbsp;\/\/&nbsp;\u5341\u516d\u8fdb\u5236\u6570&nbsp;(\u7b49\u4e8e\u5341\u8fdb\u5236&nbsp;26)<br\/>?&gt;<\/p><p>Warning &nbsp; &nbsp;<\/p><p>\u5982\u679c\u5411\u516b\u8fdb\u5236\u6570\u4f20\u9012\u4e86\u4e00\u4e2a\u975e\u6cd5\u6570\u5b57\uff08\u5373 8 \u6216 9\uff09\uff0c\u5219\u540e\u9762\u5176\u4f59\u6570\u5b57\u4f1a\u88ab\u5ffd\u7565\u3002<\/p><p>Example #2 \u516b\u8fdb\u5236\u6570\u7684\u602a\u4e8b<\/p><p>&lt;?php<br\/>var_dump(01090);&nbsp;\/\/&nbsp;\u516b\u8fdb\u5236&nbsp;010&nbsp;=&nbsp;\u5341\u8fdb\u5236&nbsp;8\uff0c\u5ffd\u7565\u4e86\u540e\u9762\u768490<br\/>?&gt;<\/p><p><br\/><\/p><p class=\"title\">\u6574\u6570\u6ea2\u51fa<\/p><p>\u5982\u679c\u7ed9\u5b9a\u7684\u4e00\u4e2a\u6570\u8d85\u51fa\u4e86 integer \u7684\u8303\u56f4\uff0c\u5c06\u4f1a\u88ab\u89e3\u91ca\u4e3a &nbsp; &nbsp;float\u3002\u540c\u6837\u5982\u679c\u6267\u884c\u7684\u8fd0\u7b97\u7ed3\u679c\u8d85\u51fa\u4e86 &nbsp; &nbsp;integer \u8303\u56f4\uff0c\u4e5f\u4f1a\u8fd4\u56de float\u3002<\/p><p>Example #3 32 \u4f4d\u7cfb\u7edf\u4e0b\u7684\u6574\u6570\u6ea2\u51fa<\/p><p>&lt;?php<br\/>$large_number&nbsp;=&nbsp;2147483647;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;int(2147483647)<br\/><br\/>$large_number&nbsp;=&nbsp;2147483648;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;float(2147483648)<br\/><br\/>$million&nbsp;=&nbsp;1000000;<br\/>$large_number&nbsp;=&nbsp;&nbsp;50000&nbsp;*&nbsp;$million;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;float(50000000000)<br\/>?&gt;<\/p><p>Example #4 64 \u4f4d\u7cfb\u7edf\u4e0b\u7684\u6574\u6570\u6ea2\u51fa<\/p><p>&lt;?php<br\/>$large_number&nbsp;=&nbsp;9223372036854775807;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;int(9223372036854775807)<br\/><br\/>$large_number&nbsp;=&nbsp;9223372036854775808;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;float(9.2233720368548E+18)<br\/><br\/>$million&nbsp;=&nbsp;1000000;<br\/>$large_number&nbsp;=&nbsp;&nbsp;50000000000000&nbsp;*&nbsp;$million;<br\/>var_dump($large_number);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;float(5.0E+19)<br\/>?&gt;<\/p><p>PHP \u4e2d\u6ca1\u6709\u6574\u9664\u7684\u8fd0\u7b97\u7b26\u30021\/2 \u4ea7\u751f\u51fa float &nbsp; &nbsp;0.5\u3002\u503c\u53ef\u4ee5\u820d\u5f03\u5c0f\u6570\u90e8\u5206\u5f3a\u5236\u8f6c\u6362\u4e3a integer\uff0c\u6216\u8005\u4f7f\u7528 &nbsp; &nbsp; round() \u51fd\u6570\u53ef\u4ee5\u66f4\u597d\u5730\u8fdb\u884c\u56db\u820d\u4e94\u5165\u3002<\/p><p>&lt;?php<br\/>var_dump(25\/7);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;float(3.5714285714286)&nbsp;<br\/>var_dump((int)&nbsp;(25\/7));&nbsp;\/\/&nbsp;int(3)<br\/>var_dump(round(25\/7));&nbsp;&nbsp;\/\/&nbsp;float(4)&nbsp;<br\/>?&gt;<\/p><p><br\/><\/p><p class=\"title\">\u4ece\u5e03\u5c14\u503c\u8f6c\u6362<\/p><p>FALSE \u5c06\u4ea7\u751f\u51fa 0\uff08\u96f6\uff09\uff0cTRUE \u5c06\u4ea7\u751f\u51fa &nbsp; &nbsp; 1\uff08\u58f9\uff09\u3002<\/p><p class=\"title\">\u4ece\u6d6e\u70b9\u578b\u8f6c\u6362<\/p><p>\u5f53\u4ece\u6d6e\u70b9\u6570\u8f6c\u6362\u6210\u6574\u6570\u65f6\uff0c\u5c06\u5411\u4e0b\u53d6\u6574\u3002<\/p><p>\u5982\u679c\u6d6e\u70b9\u6570\u8d85\u51fa\u4e86\u6574\u6570\u8303\u56f4\uff0832 \u4f4d\u5e73\u53f0\u4e0b\u901a\u5e38\u4e3a &nbsp; &nbsp; +\/- 2.15e+9 = 2^31\uff0c64 \u4f4d\u5e73\u53f0\u4e0b\u901a\u5e38\u4e3a\t +\/- 9.22e+18 = 2^63\uff09\uff0c\u5219\u7ed3\u679c\u4e3a\u672a\u5b9a\u4e49\uff0c\u56e0\u4e3a\u6ca1\u6709\u8db3\u591f\u7684\u7cbe\u5ea6\u7ed9\u51fa\u4e00\u4e2a\u786e\u5207\u7684\u6574\u6570\u7ed3\u679c\u3002\u5728\u6b64\u60c5\u51b5\u4e0b\u6ca1\u6709\u8b66\u544a\uff0c\u751a\u81f3\u6ca1\u6709\u4efb\u4f55\u901a\u77e5\uff01<\/p><p>Warning &nbsp; &nbsp;<\/p><p>\u51b3\u4e0d\u8981\u5c06\u672a\u77e5\u7684\u5206\u6570\u5f3a\u5236\u8f6c\u6362\u4e3a integer\uff0c\u8fd9\u6837\u6709\u65f6\u4f1a\u5bfc\u81f4\u4e0d\u53ef\u9884\u6599\u7684\u7ed3\u679c\u3002<\/p><p>&lt;?php<br\/>echo&nbsp;(int)&nbsp;(&nbsp;(0.1+0.7)&nbsp;*&nbsp;10&nbsp;);&nbsp;\/\/&nbsp;\u663e\u793a&nbsp;7!<br\/>?&gt;<\/p><p><br\/><\/p><p class=\"title\"><strong>3\u3001Float \u6d6e\u70b9\u578b<\/strong><\/p><p>\u6d6e\u70b9\u578b\uff08\u4e5f\u53eb\u6d6e\u70b9\u6570 float\uff0c\u53cc\u7cbe\u5ea6\u6570 double \u6216\u5b9e\u6570 real\uff09\u53ef\u4ee5\u7528\u4ee5\u4e0b\u4efb\u4e00\u8bed\u6cd5\u5b9a\u4e49\uff1a<\/p><p>&lt;?php<br\/>$a&nbsp;=&nbsp;1.234;&nbsp;<br\/>$b&nbsp;=&nbsp;1.2e3;&nbsp;<br\/>$c&nbsp;=&nbsp;7E-10;<br\/>?&gt;<\/p><p><br\/><\/p><p>Warning &nbsp;<\/p><p>\u6d6e\u70b9\u6570\u7684\u7cbe\u5ea6<\/p><p>\u6d6e\u70b9\u6570\u7684\u7cbe\u5ea6\u6709\u9650\u3002\u5c3d\u7ba1\u53d6\u51b3\u4e8e\u7cfb\u7edf\uff0cPHP \u901a\u5e38\u4f7f\u7528 IEEE 754 &nbsp; &nbsp;\u53cc\u7cbe\u5ea6\u683c\u5f0f\uff0c\u5219\u7531\u4e8e\u53d6\u6574\u800c\u5bfc\u81f4\u7684\u6700\u5927\u76f8\u5bf9\u8bef\u5dee\u4e3a &nbsp; &nbsp;1.11e-16\u3002\u975e\u57fa\u672c\u6570\u5b66\u8fd0\u7b97\u53ef\u80fd\u4f1a\u7ed9\u51fa\u66f4\u5927\u8bef\u5dee\uff0c\u5e76\u4e14\u8981\u8003\u8651\u5230\u8fdb\u884c\u590d\u5408\u8fd0\u7b97\u65f6\u7684\u8bef\u5dee\u4f20\u9012\u3002<\/p><p>\u6b64\u5916\uff0c\u4ee5\u5341\u8fdb\u5236\u80fd\u591f\u7cbe\u786e\u8868\u793a\u7684\u6709\u7406\u6570\u5982 0.1 \u6216 &nbsp; &nbsp;0.7\uff0c\u65e0\u8bba\u6709\u591a\u5c11\u5c3e\u6570\u90fd\u4e0d\u80fd\u88ab\u5185\u90e8\u6240\u4f7f\u7528\u7684\u4e8c\u8fdb\u5236\u7cbe\u786e\u8868\u793a\uff0c\u56e0\u6b64\u4e0d\u80fd\u5728\u4e0d\u4e22\u5931\u4e00\u70b9\u70b9\u7cbe\u5ea6\u7684\u60c5\u51b5\u4e0b\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u7684\u683c\u5f0f\u3002\u8fd9\u5c31\u4f1a\u9020\u6210\u6df7\u4e71\u7684\u7ed3\u679c\uff1a\u4f8b\u5982\uff0cfloor((0.1+0.7)*10) &nbsp; &nbsp;\u901a\u5e38\u4f1a\u8fd4\u56de 7 \u800c\u4e0d\u662f\u9884\u671f\u4e2d\u7684 &nbsp; &nbsp;8\uff0c\u56e0\u4e3a\u8be5\u7ed3\u679c\u5185\u90e8\u7684\u8868\u793a\u5176\u5b9e\u662f\u7c7b\u4f3c &nbsp; &nbsp;7.9999999999999991118...\u3002<\/p><p>\u6240\u4ee5\u6c38\u8fdc\u4e0d\u8981\u76f8\u4fe1\u6d6e\u70b9\u6570\u7ed3\u679c\u7cbe\u786e\u5230\u4e86\u6700\u540e\u4e00\u4f4d\uff0c\u4e5f\u6c38\u8fdc\u4e0d\u8981\u6bd4\u8f83\u4e24\u4e2a\u6d6e\u70b9\u6570\u662f\u5426\u76f8\u7b49\u3002\u5982\u679c\u786e\u5b9e\u9700\u8981\u66f4\u9ad8\u7684\u7cbe\u5ea6\uff0c\u5e94\u8be5\u4f7f\u7528\u4efb\u610f\u7cbe\u5ea6\u6570\u5b66\u51fd\u6570\u6216\u8005 gmp \u51fd\u6570\u3002<\/p><p><br\/><\/p><p>\u8f6c\u6362\u4e3a\u6d6e\u70b9\u6570<\/p><p>\u5982\u679c\u5e0c\u671b\u4e86\u89e3\u6709\u5173\u4f55\u65f6\u548c\u5982\u4f55\u5c06\u5b57\u7b26\u4e32\u8f6c\u6362\u6210\u6d6e\u70b9\u6570\u7684\u4fe1\u606f\uff0c\u8bf7\u53c2\u9605&quot;\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u6570\u503c&quot;\u4e00\u8282\u3002\u5bf9\u4e8e\u5176\u5b83\u7c7b\u578b\u7684\u503c\uff0c\u5176\u60c5\u51b5\u7c7b\u4f3c\u4e8e\u5148\u5c06\u503c\u8f6c\u6362\u6210\u6574\u578b\uff0c\u7136\u540e\u518d\u8f6c\u6362\u6210\u6d6e\u70b9\u3002\u8bf7\u53c2\u9605&quot;\u8f6c\u6362\u4e3a\u6574\u578b&quot;\u4e00\u8282\u4ee5\u83b7\u53d6\u66f4\u591a\u4fe1\u606f\u3002\u81ea &nbsp; &nbsp;PHP 5 \u8d77\uff0c\u5982\u679c\u8bd5\u56fe\u5c06\u5bf9\u8c61\u8f6c\u6362\u4e3a\u6d6e\u70b9\u6570\uff0c\u4f1a\u53d1\u51fa\u4e00\u6761 E_NOTICE \u9519\u8bef\u6d88\u606f\u3002<\/p><p>\u6bd4\u8f83\u6d6e\u70b9\u6570<\/p><p>\u5982\u4e0a\u8ff0\u8b66\u544a\u4fe1\u606f\u6240\u8a00\uff0c\u7531\u4e8e\u5185\u90e8\u8868\u8fbe\u65b9\u5f0f\u7684\u539f\u56e0\uff0c\u6bd4\u8f83\u4e24\u4e2a\u6d6e\u70b9\u6570\u662f\u5426\u76f8\u7b49\u662f\u6709\u95ee\u9898\u7684\u3002\u4e0d\u8fc7\u8fd8\u662f\u6709\u8fc2\u56de\u7684\u65b9\u6cd5\u6765\u6bd4\u8f83\u6d6e\u70b9\u6570\u503c\u7684\u3002<\/p><p>\u8981\u6d4b\u8bd5\u6d6e\u70b9\u6570\u662f\u5426\u76f8\u7b49\uff0c\u8981\u4f7f\u7528\u4e00\u4e2a\u4ec5\u6bd4\u8be5\u6570\u503c\u5927\u4e00\u4e01\u70b9\u7684\u6700\u5c0f\u8bef\u5dee\u503c\u3002\u8be5\u503c\u4e5f\u88ab\u79f0\u4e3a\u673a\u5668\u6781\u5c0f\u503c\uff08epsilon\uff09\u6216\u6700\u5c0f\u5355\u5143\u53d6\u6574\u6570\uff0c\u662f\u8ba1\u7b97\u4e2d\u6240\u80fd\u63a5\u53d7\u7684\u6700\u5c0f\u7684\u5dee\u522b\u503c\u3002<\/p><p>$a\u548c$b\u5728\u5c0f\u6570\u70b9\u540e\u4e94\u4f4d\u7cbe\u5ea6\u5185\u90fd\u662f\u76f8\u7b49\u7684\u3002<\/p><p>&lt;?php<br\/>$a&nbsp;=&nbsp;1.23456789;<br\/>$b&nbsp;=&nbsp;1.23456780;<br\/>$epsilon&nbsp;=&nbsp;0.00001;<br\/><br\/>if(abs($a-$b)&nbsp;&lt;&nbsp;$epsilon)&nbsp;{<br\/>&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;&quot;true&quot;;<br\/>}<br\/>?&gt;<\/p><p>NaN<\/p><p>\u67d0\u4e9b\u6570\u5b66\u8fd0\u7b97\u4f1a\u4ea7\u751f\u4e00\u4e2a\u7531\u5e38\u91cf NAN &nbsp; &nbsp;\u6240\u4ee3\u8868\u7684\u7ed3\u679c\u3002\u6b64\u7ed3\u679c\u4ee3\u8868\u7740\u4e00\u4e2a\u5728\u6d6e\u70b9\u6570\u8fd0\u7b97\u4e2d\u672a\u5b9a\u4e49\u6216\u4e0d\u53ef\u8868\u8ff0\u7684\u503c\u3002\u4efb\u4f55\u62ff\u6b64\u503c\u4e0e\u5176\u5b83\u4efb\u4f55\u503c\u8fdb\u884c\u7684\u677e\u6563\u6216\u4e25\u683c\u6bd4\u8f83\u7684\u7ed3\u679c\u90fd\u662f &nbsp; &nbsp;FALSE\u3002<\/p><p>\u7531\u4e8e NAN \u4ee3\u8868\u7740\u4efb\u4f55\u4e0d\u540c\u503c\uff0c\u4e0d\u5e94\u62ff &nbsp; &nbsp;NAN \u53bb\u548c\u5176\u5b83\u503c\u8fdb\u884c\u6bd4\u8f83\uff0c\u5305\u62ec\u5176\u81ea\u8eab\uff0c\u5e94\u8be5\u7528 &nbsp; &nbsp; is_nan() \u6765\u68c0\u67e5\u3002<\/p><p><br\/><\/p><p><strong>4\u3001\u5b57\u7b26\u4e32<\/strong><\/p><p><br\/><\/p><p class=\"title\">String \u5b57\u7b26\u4e32<\/p><p>\u4e00\u4e2a\u5b57\u7b26\u4e32 string \u5c31\u662f\u7531\u4e00\u7cfb\u5217\u7684\u5b57\u7b26\u7ec4\u6210\uff0c\u5176\u4e2d\u6bcf\u4e2a\u5b57\u7b26\u7b49\u540c\u4e8e\u4e00\u4e2a\u5b57\u8282\u3002\u8fd9\u610f\u5473\u7740 &nbsp; PHP \u53ea\u80fd\u652f\u6301 256 \u7684\u5b57\u7b26\u96c6\uff0c\u56e0\u6b64\u4e0d\u652f\u6301 Unicode \u3002\u8be6\u89c1\u5b57\u7b26\u4e32\u7c7b\u578b\u8be6\u89e3\u3002<\/p><p>Note: &nbsp; &nbsp;string \u6700\u5927\u53ef\u4ee5\u8fbe\u5230 2GB\u3002<\/p><p class=\"title\">\u5355\u5f15\u53f7<\/p><p>\u5b9a\u4e49\u4e00\u4e2a\u5b57\u7b26\u4e32\u7684\u6700\u7b80\u5355\u7684\u65b9\u6cd5\u662f\u7528\u5355\u5f15\u53f7\u628a\u5b83\u5305\u56f4\u8d77\u6765\uff08\u5b57\u7b26 &#39;\uff09\u3002<\/p><p class=\"title\">\u53cc\u5f15\u53f7<\/p><p>\u5982\u679c\u5b57\u7b26\u4e32\u662f\u5305\u56f4\u5728\u53cc\u5f15\u53f7\uff08&quot;\uff09\u4e2d\uff0c PHP \u5c06\u5bf9\u4e00\u4e9b\u7279\u6b8a\u7684\u5b57\u7b26\u8fdb\u884c\u89e3\u6790\uff1a<\/p><p>\u8f6c\u4e49\u5b57\u7b26<\/p><p><br\/><\/p><p>\u5e8f\u5217<\/p><p>\u542b\u4e49<\/p><p><br\/><\/p><p>n &nbsp; &nbsp;\u6362\u884c\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 LF \u6216 0x0A (10)\uff09 &nbsp; &nbsp;<\/p><p>r &nbsp; &nbsp;\u56de\u8f66\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 CR \u6216 0x0D (13)\uff09 &nbsp; &nbsp;<\/p><p>t &nbsp; &nbsp;\u6c34\u5e73\u5236\u8868\u7b26\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 HT \u6216 0x09 (9)\uff09 &nbsp; &nbsp;<\/p><p>v &nbsp; &nbsp;\u5782\u76f4\u5236\u8868\u7b26\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 VT \u6216 0x0B (11)\uff09\uff08\u81ea PHP 5.2.5 \u8d77\uff09 &nbsp; &nbsp;<\/p><p>e &nbsp; &nbsp;Escape\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 ESC \u6216 0x1B (27)\uff09\uff08\u81ea PHP 5.4.0 \u8d77\uff09 &nbsp; &nbsp;<\/p><p>f &nbsp; &nbsp;\u6362\u9875\uff08ASCII \u5b57\u7b26\u96c6\u4e2d\u7684 FF \u6216 0x0C (12)\uff09\uff08\u81ea PHP 5.2.5 \u8d77\uff09 &nbsp; &nbsp;<\/p><p>&nbsp; &nbsp;\u53cd\u659c\u7ebf &nbsp; &nbsp;<\/p><p>$ &nbsp; &nbsp;\u7f8e\u5143\u6807\u8bb0 &nbsp; &nbsp;<\/p><p>&quot; &nbsp; &nbsp;\u53cc\u5f15\u53f7 &nbsp; &nbsp;<\/p><p>[0-7]{1,3} &nbsp; &nbsp;\u7b26\u5408\u8be5\u6b63\u5219\u8868\u8fbe\u5f0f\u5e8f\u5217\u7684\u662f\u4e00\u4e2a\u4ee5\u516b\u8fdb\u5236\u65b9\u5f0f\u6765\u8868\u8fbe\u7684\u5b57\u7b26 &nbsp; &nbsp;<\/p><p>x[0-9A-Fa-f]{1,2} &nbsp; &nbsp;\u7b26\u5408\u8be5\u6b63\u5219\u8868\u8fbe\u5f0f\u5e8f\u5217\u7684\u662f\u4e00\u4e2a\u4ee5\u5341\u516d\u8fdb\u5236\u65b9\u5f0f\u6765\u8868\u8fbe\u7684\u5b57\u7b26 &nbsp; &nbsp;<\/p><p><br\/><\/p><p>Example #9 \u4e00\u4e9b\u5b57\u7b26\u4e32\u793a\u4f8b<\/p><p>&lt;?php<br\/>\/\/&nbsp;\u53d6\u5f97\u5b57\u7b26\u4e32\u7684\u7b2c\u4e00\u4e2a\u5b57\u7b26<br\/>$str&nbsp;=&nbsp;&#39;This&nbsp;is&nbsp;a&nbsp;test.&#39;;<br\/>$first&nbsp;=&nbsp;$str[0];<br\/><br\/>\/\/&nbsp;\u53d6\u5f97\u5b57\u7b26\u4e32\u7684\u7b2c\u4e09\u4e2a\u5b57\u7b26<br\/>$third&nbsp;=&nbsp;$str[2];<br\/><br\/>\/\/&nbsp;\u53d6\u5f97\u5b57\u7b26\u4e32\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u7b26<br\/>$str&nbsp;=&nbsp;&#39;This&nbsp;is&nbsp;still&nbsp;a&nbsp;test.&#39;;<br\/>$last&nbsp;=&nbsp;$str[strlen($str)-1];&nbsp;<br\/><br\/>\/\/&nbsp;\u4fee\u6539\u5b57\u7b26\u4e32\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u7b26<br\/>$str&nbsp;=&nbsp;&#39;Look&nbsp;at&nbsp;the&nbsp;sea&#39;;<br\/>$str[strlen($str)-1]&nbsp;=&nbsp;&#39;e&#39;;<br\/><br\/>?&gt;<\/p><p class=\"title\">\u8f6c\u6362\u6210\u5b57\u7b26\u4e32<\/p><p>\u4e00\u4e2a\u503c\u53ef\u4ee5\u901a\u8fc7\u5728\u5176\u524d\u9762\u52a0\u4e0a (string) \u6216\u7528 &nbsp;strval() &nbsp; &nbsp;\u51fd\u6570\u6765\u8f6c\u53d8\u6210\u5b57\u7b26\u4e32\u3002\u5728\u4e00\u4e2a\u9700\u8981\u5b57\u7b26\u4e32\u7684\u8868\u8fbe\u5f0f\u4e2d\uff0c\u4f1a\u81ea\u52a8\u8f6c\u6362\u4e3a &nbsp; &nbsp;string\u3002\u6bd4\u5982\u5728\u4f7f\u7528\u51fd\u6570 &nbsp;echo \u6216 &nbsp;print &nbsp; &nbsp;\u65f6\uff0c\u6216\u5728\u4e00\u4e2a\u53d8\u91cf\u548c\u4e00\u4e2a string \u8fdb\u884c\u6bd4\u8f83\u65f6\uff0c\u5c31\u4f1a\u53d1\u751f\u8fd9\u79cd\u8f6c\u6362\u3002\u7c7b\u578b\u548c\u7c7b\u578b\u8f6c\u6362\u53ef\u4ee5\u66f4\u597d\u7684\u89e3\u91ca\u4e0b\u9762\u7684\u4e8b\u60c5\uff0c\u4e5f\u53ef\u53c2\u8003\u51fd\u6570 &nbsp; &nbsp; settype()\u3002<\/p><p>\u4e00\u4e2a\u5e03\u5c14\u503c boolean \u7684 TRUE \u88ab\u8f6c\u6362\u6210 string \u7684 &nbsp; &nbsp;&quot;1&quot;\u3002Boolean \u7684 FALSE \u88ab\u8f6c\u6362\u6210 &nbsp; &nbsp;&quot;&quot;\uff08\u7a7a\u5b57\u7b26\u4e32\uff09\u3002\u8fd9\u79cd\u8f6c\u6362\u53ef\u4ee5\u5728 boolean &nbsp; &nbsp;\u548c string \u4e4b\u95f4\u76f8\u4e92\u8fdb\u884c\u3002<\/p><p>\u4e00\u4e2a\u6574\u6570 integer \u6216\u6d6e\u70b9\u6570 float \u88ab\u8f6c\u6362\u4e3a\u6570\u5b57\u7684\u5b57\u9762\u6837\u5f0f\u7684 &nbsp; &nbsp;string\uff08\u5305\u62ec float &nbsp; &nbsp;\u4e2d\u7684\u6307\u6570\u90e8\u5206\uff09\u3002\u4f7f\u7528\u6307\u6570\u8ba1\u6570\u6cd5\u7684\u6d6e\u70b9\u6570\uff084.1E+6\uff09\u4e5f\u53ef\u8f6c\u6362\u3002<\/p><p>&lt;?php<br\/>$foo&nbsp;=&nbsp;1&nbsp;+&nbsp;&quot;10.5&quot;;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;float&nbsp;(11.5)<br\/>$foo&nbsp;=&nbsp;1&nbsp;+&nbsp;&quot;-1.3e3&quot;;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;float&nbsp;(-1299)<br\/>$foo&nbsp;=&nbsp;1&nbsp;+&nbsp;&quot;bob-1.3e3&quot;;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;integer&nbsp;(1)<br\/>$foo&nbsp;=&nbsp;1&nbsp;+&nbsp;&quot;bob3&quot;;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;integer&nbsp;(1)<br\/>$foo&nbsp;=&nbsp;1&nbsp;+&nbsp;&quot;10&nbsp;Small&nbsp;Pigs&quot;;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;integer&nbsp;(11)<br\/>$foo&nbsp;=&nbsp;4&nbsp;+&nbsp;&quot;10.2&nbsp;Little&nbsp;Piggies&quot;;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;float&nbsp;(14.2)<br\/>$foo&nbsp;=&nbsp;&quot;10.0&nbsp;pigs&nbsp;&quot;&nbsp;+&nbsp;1;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;float&nbsp;(11)<br\/>$foo&nbsp;=&nbsp;&quot;10.0&nbsp;pigs&nbsp;&quot;&nbsp;+&nbsp;1.0;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\/\/&nbsp;$foo&nbsp;is&nbsp;float&nbsp;(11)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br\/>?&gt;<\/p><p><br\/><\/p><p class=\"title\"><strong>5\u3001\u6570\u7ec4<\/strong> &nbsp;array()<\/p><p>\u53ef\u4ee5\u7528 &nbsp;array() \u8bed\u8a00\u7ed3\u6784\u6765\u65b0\u5efa\u4e00\u4e2a\u6570\u7ec4\u3002\u5b83\u63a5\u53d7\u4efb\u610f\u6570\u91cf\u7528\u9017\u53f7\u5206\u9694\u7684 &nbsp; &nbsp; \u952e\uff08key\uff09 =&gt; \u503c\uff08value\uff09\u5bf9\u3002<\/p><p>array( &nbsp;key =&gt; &nbsp;value<br\/> &nbsp; &nbsp; , ...<br\/> &nbsp; &nbsp; )<br\/>\/\/ \u952e\uff08key\uff09<strong>\u53ef\u662f\u662f\u4e00\u4e2a\u6574\u6570 integer \u6216\u5b57\u7b26\u4e32 string<\/strong><\/p><p>\/\/ \u503c\uff08value\uff09\u53ef\u4ee5\u662f\u4efb\u610f\u7c7b\u578b\u7684\u503c<br\/><\/p><p>\u6b64\u5916 key \u4f1a\u6709\u5982\u4e0b\u7684\u5f3a\u5236\u8f6c\u6362\uff1a<\/p><p><\/p><ul class=\" list-paddingleft-2\"><li><p>&nbsp; &nbsp; &nbsp; \u5305\u542b\u6709\u5408\u6cd5\u6574\u578b\u503c\u7684\u5b57\u7b26\u4e32\u4f1a\u88ab\u8f6c\u6362\u4e3a\u6574\u578b\u3002\u4f8b\u5982\u952e\u540d\t &nbsp; &nbsp;&quot;8&quot; \u5b9e\u9645\u4f1a\u88ab\u50a8\u5b58\u4e3a &nbsp; &nbsp; &nbsp; &nbsp;8\u3002\u4f46\u662f &quot;08&quot;\t &nbsp; &nbsp;\u5219\u4e0d\u4f1a\u5f3a\u5236\u8f6c\u6362\uff0c\u56e0\u4e3a\u5176\u4e0d\u662f\u4e00\u4e2a\u5408\u6cd5\u7684\u5341\u8fdb\u5236\u6570\u503c\u3002 &nbsp; &nbsp; &nbsp;<\/p><\/li><li><p>&nbsp; &nbsp; &nbsp; \u6d6e\u70b9\u6570\u4e5f\u4f1a\u88ab\u8f6c\u6362\u4e3a\u6574\u578b\uff0c\u610f\u5473\u7740\u5176\u5c0f\u6570\u90e8\u5206\u4f1a\u88ab\u820d\u53bb\u3002\u4f8b\u5982\u952e\u540d\t &nbsp; &nbsp;8.7 \u5b9e\u9645\u4f1a\u88ab\u50a8\u5b58\u4e3a 8\u3002 &nbsp; &nbsp; &nbsp;<\/p><\/li><li><p>&nbsp; &nbsp; &nbsp; \u5e03\u5c14\u503c\u4e5f\u4f1a\u88ab\u8f6c\u6362\u6210\u6574\u578b\u3002\u5373\u952e\u540d &nbsp; &nbsp; &nbsp; &nbsp;true \u5b9e\u9645\u4f1a\u88ab\u50a8\u5b58\u4e3a 1\t &nbsp; &nbsp;\u800c\u952e\u540d false \u4f1a\u88ab\u50a8\u5b58\u4e3a 0\u3002 &nbsp; &nbsp; &nbsp;<\/p><\/li><li><p>Null \u4f1a\u88ab\u8f6c\u6362\u4e3a\u7a7a\u5b57\u7b26\u4e32\uff0c\u5373\u952e\u540d &nbsp; &nbsp; &nbsp; &nbsp;null \u5b9e\u9645\u4f1a\u88ab\u50a8\u5b58\u4e3a &quot;&quot;\u3002 &nbsp; &nbsp; &nbsp;<\/p><\/li><li><p>&nbsp; &nbsp; &nbsp; \u6570\u7ec4\u548c\u5bf9\u8c61\u4e0d\u80fd\u88ab\u7528\u4e3a\u952e\u540d\u3002\u575a\u6301\u8fd9\u4e48\u505a\u4f1a\u5bfc\u81f4\u8b66\u544a\uff1aIllegal offset type\u3002 &nbsp; &nbsp; &nbsp;<\/p><\/li><\/ul><p><\/p><p>\u5982\u679c\u5728\u6570\u7ec4\u5b9a\u4e49\u4e2d\u591a\u4e2a\u5355\u5143\u90fd\u4f7f\u7528\u4e86\u540c\u4e00\u4e2a\u952e\u540d\uff0c\u5219\u53ea\u4f7f\u7528\u4e86\u6700\u540e\u4e00\u4e2a\uff0c\u4e4b\u524d\u7684\u90fd\u88ab\u8986\u76d6\u4e86\u3002<\/p><p>Example #2 \u7c7b\u578b\u5f3a\u5236\u4e0e\u8986\u76d6\u793a\u4f8b<\/p><p>&lt;?php<br\/>$array&nbsp;=&nbsp;array(<br\/>&nbsp;&nbsp;&nbsp;&nbsp;1&nbsp;&nbsp;&nbsp;&nbsp;=&gt;&nbsp;&quot;a&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;&quot;1&quot;&nbsp;&nbsp;=&gt;&nbsp;&quot;b&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;1.5&nbsp;&nbsp;=&gt;&nbsp;&quot;c&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;true&nbsp;=&gt;&nbsp;&quot;d&quot;,<br\/>);<br\/>var_dump($array);<br\/>?&gt;<\/p><p>\u4ee5\u4e0a\u4f8b\u7a0b\u4f1a\u8f93\u51fa\uff1a<\/p><p>array(1) {<br\/> &nbsp;[1]=&gt;<br\/> &nbsp;string(1) &quot;d&quot;<br\/>}<br\/><\/p><p><br\/><\/p><p>Example #5 \u4ec5\u5bf9\u90e8\u5206\u5355\u5143\u6307\u5b9a\u952e\u540d<\/p><p>&lt;?php<br\/>$array&nbsp;=&nbsp;array(<br\/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;a&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;b&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;6&nbsp;=&gt;&nbsp;&quot;c&quot;,<br\/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;d&quot;,<br\/>);<br\/>var_dump($array);<br\/>?&gt;<\/p><p>\u4ee5\u4e0a\u4f8b\u7a0b\u4f1a\u8f93\u51fa\uff1a<\/p><p>array(4) {<br\/> &nbsp;[0]=&gt;<br\/> &nbsp;string(1) &quot;a&quot;<br\/> &nbsp;[1]=&gt;<br\/> &nbsp;string(1) &quot;b&quot;<br\/> &nbsp;[6]=&gt;<br\/> &nbsp;string(1) &quot;c&quot;<br\/> &nbsp;[7]=&gt;<br\/> &nbsp;string(1) &quot;d&quot;<br\/>}<br\/><\/p><p><br\/><\/p><p>Note:<\/p><p>\u5982\u4e0a\u6240\u8ff0\uff0c\u5982\u679c\u7ed9\u51fa\u65b9\u62ec\u53f7\u4f46\u6ca1\u6709\u6307\u5b9a\u952e\u540d\uff0c\u5219\u53d6\u5f53\u524d\u6700\u5927\u6574\u6570\u7d22\u5f15\u503c\uff0c\u65b0\u7684\u952e\u540d\u5c06\u662f\u8be5\u503c\u52a0\u4e0a &nbsp; &nbsp; &nbsp;1\uff08\u4f46\u662f\u6700\u5c0f\u4e3a 0\uff09\u3002\u5982\u679c\u5f53\u524d\u8fd8\u6ca1\u6709\u6574\u6570\u7d22\u5f15\uff0c\u5219\u952e\u540d\u5c06\u4e3a &nbsp; &nbsp; &nbsp;0\u3002<\/p><p>\u6ce8\u610f\u8fd9\u91cc\u6240\u4f7f\u7528\u7684\u6700\u5927\u6574\u6570\u952e\u540d\u4e0d\u4e00\u5b9a\u5f53\u524d\u5c31\u5728\u6570\u7ec4\u4e2d\u3002\u5b83\u53ea\u8981\u5728\u4e0a\u6b21\u6570\u7ec4\u91cd\u65b0\u751f\u6210\u7d22\u5f15\u540e\u66fe\u7ecf\u5b58\u5728\u8fc7\u5c31\u884c\u4e86\u3002\u4ee5\u4e0b\u9762\u7684\u4f8b\u5b50\u6765\u8bf4\u660e\uff1a<\/p><p>&lt;?php<br\/>\/\/&nbsp;\u521b\u5efa\u4e00\u4e2a\u7b80\u5355\u7684\u6570\u7ec4<br\/>$array&nbsp;=&nbsp;array(1,&nbsp;2,&nbsp;3,&nbsp;4,&nbsp;5);<br\/>print_r($array);<br\/><br\/>\/\/&nbsp;\u73b0\u5728\u5220\u9664\u5176\u4e2d\u7684\u6240\u6709\u5143\u7d20\uff0c\u4f46\u4fdd\u6301\u6570\u7ec4\u672c\u8eab\u4e0d\u53d8:<br\/>foreach&nbsp;($array&nbsp;as&nbsp;$i&nbsp;=&gt;&nbsp;$value)&nbsp;{<br\/>&nbsp;&nbsp;&nbsp;&nbsp;unset($array[$i]);<br\/>}<br\/>print_r($array);<br\/><br\/>\/\/&nbsp;\u6dfb\u52a0\u4e00\u4e2a\u5355\u5143\uff08\u6ce8\u610f\u65b0\u7684\u952e\u540d\u662f&nbsp;5\uff0c\u800c\u4e0d\u662f\u4f60\u53ef\u80fd\u4ee5\u4e3a\u7684&nbsp;0\uff09<br\/>$array[]&nbsp;=&nbsp;6;<br\/>print_r($array);<br\/><br\/>\/\/&nbsp;\u91cd\u65b0\u7d22\u5f15\uff1a<br\/>$array&nbsp;=&nbsp;array_values($array);<br\/>$array[]&nbsp;=&nbsp;7;<br\/>print_r($array);<br\/>?&gt;<\/p><p>\u4ee5\u4e0a\u4f8b\u7a0b\u4f1a\u8f93\u51fa\uff1a<\/p><p>Array<br\/>(<br\/> &nbsp; &nbsp;[0] =&gt; 1<br\/> &nbsp; &nbsp;[1] =&gt; 2<br\/> &nbsp; &nbsp;[2] =&gt; 3<br\/> &nbsp; &nbsp;[3] =&gt; 4<br\/> &nbsp; &nbsp;[4] =&gt; 5<br\/>)<br\/>Array<br\/>(<br\/>)<br\/>Array<br\/>(<br\/> &nbsp; &nbsp;[5] =&gt; 6<br\/>)<br\/>Array<br\/>(<br\/> &nbsp; &nbsp;[0] =&gt; 6<br\/> &nbsp; &nbsp;[1] =&gt; 7<br\/>)<br\/><\/p><p><br\/><\/p>"}