PHP determines if a string is included

1. Usage of STRSTR and STRISTR

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strstr: 返回一个从被判断字符开始到结束的字符串,如果没有返回值,则不包含. stristr: 它和strstr的使用方法完全一样.唯一的区别是stristr不区分大小写.$email = ‘ [email protected]’;$domain = strstr($email, ‘@’);echo$domain;// prints @example.com

2. Usage of Strpos

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strpos: 返回boolean值.FALSE和TRUE不用多说.用 “===”进行判断.strpos在执行速度上都比以上两个函数快,另外strpos有一个参数指定判断的位置,但是默认为空.意思是判断整个字符串.缺点是对中文的支持不好.PHP判断字符串的包含代码如下:    $str= ‘abc’;    $needle= ‘a’;    $pos = strpos($str, $needle);

3. Usage of explode

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用explode进行判断PHP判断字符串的包含代码如下:    function checkstr($str){    $needle = “a”;//判断是否包含a这个字符    $tmparray = explode($needle,$str);    if(count($tmparray)>1){    return true;    } else{    return false;    }    }

4.in_array-Check if there is a value example in the array

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1. in_array() 例子<?php$os= array("Mac", "NT", "Irix", "Linux");if (in_array("Irix", $os)) {echo"Got Irix";}if (  in_array("mac", $os)) {echo"Got mac";}?>第二个条件失败，因为 in_array() 是区分大小写的，所以以上程序显示为：Got Irix2. in_array() 严格类型检查例子<?php$a= array(‘1.10‘, 12.4, 1.13);if (in_array(‘12.4‘, $a, true)) {echo"‘12.4‘ found with strict check\n";}if (in_array(1.13, $a, true)) {echo"1.13 found with strict check\n";}?>上例将输出：1.13 found with strict check3. in_array() 中用数组作为 needle<?php$a= array(array(‘p‘, ‘h‘), array(‘p‘, ‘r‘), ‘o‘);if (in_array(array(‘p‘, ‘h‘), $a)) {echo"‘ph‘ was found\n";}if (in_array(array(‘f‘, ‘i‘), $a)) {echo"‘fi‘ was found\n";}if (in_array(‘o‘, $a)) {echo"‘o‘ was found\n";}?>上例将输出：‘ph‘ was found‘o‘ was foundarray_search — 在数组中搜索给定的值，如果成功则返回相应的键名

PHP determines if a string is included