blocks|key|1128597|text|您可以使用preg_grep()|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1128598|$a=+array(
+'one',
+'two',
+'three',
+'four'
);

print_r(+preg_grep(+"/ONe/i"+,+$a+)+);|code-block|syntax|javascript|1128599|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/preg_grep^0|5|B|5|B|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

you can use <a href="http://php.net/preg_grep" rel="noreferrer"><code>preg_grep()</code></a>:

<pre><code>$a= array(
 'one',
 'two',
 'three',
 'four'
);

print_r( preg_grep( "/ONe/i" , $a ) );
</code></pre>

blocks|key|1128587|text|function+in_arrayi($needle,+$haystack)+{
++++return+in_array(strtolower($needle),+array_map('strtolower',+$haystack));
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1128588|来自Documentation|unstyled|offset|length|1128589|entityMap|0|LINK|mutability|MUTABLE|url|http://us2.php.net/manual/en/function.in-array.php^0|0|2|D|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>function in_arrayi($needle, $haystack) {
 return in_array(strtolower($needle), array_map('strtolower', $haystack));
}
</code></pre>

From <a href="http://us2.php.net/manual/en/function.in-array.php" rel="noreferrer">Documentation</a>

blocks|key|1343823|text|function+in_arrayi($needle,+$haystack)+{
++++return+in_array(strtolower($needle),+array_map('strtolower',+$haystack));
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1343824|来源：php.net+in_array+manual+page.|unstyled|offset|length|1343825|entityMap|0|LINK|mutability|MUTABLE|url|http://uk.php.net/manual/en/function.in-array.php#89256^0|0|3|T|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>function in_arrayi($needle, $haystack) {
 return in_array(strtolower($needle), array_map('strtolower', $haystack));
}
</code></pre>

Source: <a href="http://uk.php.net/manual/en/function.in-array.php#89256" rel="noreferrer">php.net in_array manual page.</a>

blocks|key|1128731|text|假设您想使用in_array，下面是如何使搜索不区分大小写的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1128732|不区分大小写的in_array()：|1128733|foreach($searchKey+as+$key+=>+$subkey)+{

+++++if+(in_array(strtolower($subkey),+array_map("strtolower",+$subarray)))
+++++{
++++++++echo+"found";
+++++}

}|code-block|syntax|javascript|1128734|正常区分大小写：|1128735|foreach($searchKey+as+$key+=>+$subkey)+{

if+(in_array("$subkey",+$subarray))

+++++{
++++++++echo+"found";
+++++}

}|1128736|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Say you want to use the in_array, here is how you can make the search case insensitive.

Case insensitive in_array():

<pre><code>foreach($searchKey as $key =&gt; $subkey) {

 if (in_array(strtolower($subkey), array_map("strtolower", $subarray)))
 {
 echo "found";
 }

}
</code></pre>

Normal case sensitive:

<pre><code>foreach($searchKey as $key =&gt; $subkey) {

if (in_array("$subkey", $subarray))

 {
 echo "found";
 }

}
</code></pre>

blocks|key|1128657|text|如果我们假设数组只能包含字符串，但数组也可以包含其他数组，那么上面的结论是正确的。此外，in_array()函数可以接受$needle的数组，因此如果$needle是数组，strtolower($needle)将不起作用，而如果$needle包含其他数组，则array_map('strtolower'，$haystack)将不起作用，但将导致“$haystack警告:+strtolower()要求参数1为字符串，给定的数组”。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1128658|示例：|1128659|$needle+=+array('p',+'H');
$haystack+=+array(array('p',+'H'),+'U');|code-block|syntax|javascript|1128660|因此，我创建了一个带有相关方法的助手类，以进行区分大小写和不区分大小写的in_array()检查。我还使用了mb_strtolower()而不是strtolower()，所以可以使用其他编码。代码如下：|1128661|class+StringHelper+{

public+static+function+toLower($string,+$encoding+=+'UTF-8')
{
++++return+mb_strtolower($string,+$encoding);
}

/**
+*+Digs+into+all+levels+of+an+array+and+converts+all+string+values+to+lowercase
+*/
public+static+function+arrayToLower($array)
{
++++foreach+($array+as+&$value)+{
++++++++switch+(true)+{
++++++++++++case+is_string($value):
++++++++++++++++$value+=+self::toLower($value);
++++++++++++++++break;
++++++++++++case+is_array($value):
++++++++++++++++$value+=+self::arrayToLower($value);
++++++++++++++++break;
++++++++}
++++}
++++return+$array;
}

/**
+*+Works+like+the+built-in+PHP+in_array()+function+—+Checks+if+a+value+exists+in+an+array,+but
+*+gives+the+option+to+choose+how+the+comparison+is+done+-+case-sensitive+or+case-insensitive
+*/
public+static+function+inArray($needle,+$haystack,+$case+=+'case-sensitive',+$strict+=+false)
{
++++switch+($case)+{
++++++++default:
++++++++case+'case-sensitive':
++++++++case+'cs':
++++++++++++return+in_array($needle,+$haystack,+$strict);
++++++++++++break;
++++++++case+'case-insensitive':
++++++++case+'ci':
++++++++++++if+(is_array($needle))+{
++++++++++++++++return+in_array(self::arrayToLower($needle),+self::arrayToLower($haystack),+$strict);
++++++++++++}+else+{
++++++++++++++++return+in_array(self::toLower($needle),+self::arrayToLower($haystack),+$strict);
++++++++++++}
++++++++++++break;
++++}
}
}|1128662|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

The above is correct if we assume that arrays can contain only strings, but arrays can contain other arrays as well. Also in_array() function can accept an array for $needle, so strtolower($needle) is not going to work if $needle is an array and array_map('strtolower', $haystack) is not going to work if $haystack contains other arrays, but will result in "PHP warning: strtolower() expects parameter 1 to be string, array given".

Example:

<pre><code>$needle = array('p', 'H');
$haystack = array(array('p', 'H'), 'U');
</code></pre>

So i created a helper class with the releveant methods, to make case-sensitive and case-insensitive in_array() checks. I am also using mb_strtolower() instead of strtolower(), so other encodings can be used. Here's the code:

<pre><code>class StringHelper {

public static function toLower($string, $encoding = 'UTF-8')
{
 return mb_strtolower($string, $encoding);
}

/**
 * Digs into all levels of an array and converts all string values to lowercase
 */
public static function arrayToLower($array)
{
 foreach ($array as &amp;$value) {
 switch (true) {
 case is_string($value):
 $value = self::toLower($value);
 break;
 case is_array($value):
 $value = self::arrayToLower($value);
 break;
 }
 }
 return $array;
}

/**
 * Works like the built-in PHP in_array() function — Checks if a value exists in an array, but
 * gives the option to choose how the comparison is done - case-sensitive or case-insensitive
 */
public static function inArray($needle, $haystack, $case = 'case-sensitive', $strict = false)
{
 switch ($case) {
 default:
 case 'case-sensitive':
 case 'cs':
 return in_array($needle, $haystack, $strict);
 break;
 case 'case-insensitive':
 case 'ci':
 if (is_array($needle)) {
 return in_array(self::arrayToLower($needle), self::arrayToLower($haystack), $strict);
 } else {
 return in_array(self::toLower($needle), self::arrayToLower($haystack), $strict);
 }
 break;
 }
}
}
</code></pre>

blocks|key|1344010|text|/**
+*+in_array+function+variant+that+performs+case-insensitive+comparison+when+needle+is+a+string.
+*
+*+@param+mixed+$needle
+*+@param+array+$haystack
+*+@param+bool+$strict
+*
+*+@return+bool
+*/
function+in_arrayi($needle,+array+$haystack,+bool+$strict+=+false):+bool
{

++++if+(is_string($needle))+{

++++++++$needle+=+strtolower($needle);

++++++++foreach+($haystack+as+$value)+{

++++++++++++if+(is_string($value))+{
++++++++++++++++if+(strtolower($value)+===+$needle)+{
++++++++++++++++++++return+true;
++++++++++++++++}
++++++++++++}

++++++++}

++++++++return+false;

++++}

++++return+in_array($needle,+$haystack,+$strict);

}


/**
+*+in_array+function+variant+that+performs+case-insensitive+comparison+when+needle+is+a+string.
+*+Multibyte+version.
+*
+*+@param+mixed+$needle
+*+@param+array+$haystack
+*+@param+bool+$strict
+*+@param+string%7Cnull+$encoding
+*
+*+@return+bool
+*/
function+mb_in_arrayi($needle,+array+$haystack,+bool+$strict+=+false,+?string+$encoding+=+null):+bool
{

++++if+(null+===+$encoding)+{
++++++++$encoding+=+mb_internal_encoding();
++++}

++++if+(is_string($needle))+{

++++++++$needle+=+mb_strtolower($needle,+$encoding);

++++++++foreach+($haystack+as+$value)+{

++++++++++++if+(is_string($value))+{
++++++++++++++++if+(mb_strtolower($value,+$encoding)+===+$needle)+{
++++++++++++++++++++return+true;
++++++++++++++++}
++++++++++++}

++++++++}

++++++++return+false;

++++}

++++return+in_array($needle,+$haystack,+$strict);

}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1344011|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>/**
 * in_array function variant that performs case-insensitive comparison when needle is a string.
 *
 * @param mixed $needle
 * @param array $haystack
 * @param bool $strict
 *
 * @return bool
 */
function in_arrayi($needle, array $haystack, bool $strict = false): bool
{

 if (is_string($needle)) {

 $needle = strtolower($needle);

 foreach ($haystack as $value) {

 if (is_string($value)) {
 if (strtolower($value) === $needle) {
 return true;
 }
 }

 }

 return false;

 }

 return in_array($needle, $haystack, $strict);

}


/**
 * in_array function variant that performs case-insensitive comparison when needle is a string.
 * Multibyte version.
 *
 * @param mixed $needle
 * @param array $haystack
 * @param bool $strict
 * @param string|null $encoding
 *
 * @return bool
 */
function mb_in_arrayi($needle, array $haystack, bool $strict = false, ?string $encoding = null): bool
{

 if (null === $encoding) {
 $encoding = mb_internal_encoding();
 }

 if (is_string($needle)) {

 $needle = mb_strtolower($needle, $encoding);

 foreach ($haystack as $value) {

 if (is_string($value)) {
 if (mb_strtolower($value, $encoding) === $needle) {
 return true;
 }
 }

 }

 return false;

 }

 return in_array($needle, $haystack, $strict);

}
</code></pre>

blocks|key|1128685|text|$a+=+[1+=>+'funny',+3+=>+'meshgaat',+15+=>+'obi',+2+=>+'OMER'];++

$b+=+'omer';

function+checkArr($x,$array)
{
++++$arr+=+array_values($array);
++++$arrlength+=+count($arr);
++++$z+=+strtolower($x);

++++for+($i+=+0;+$i+<+$arrlength;+$i%2B%2B)+{
++++++++if+($z+==+strtolower($arr[$i]))+{
++++++++++++echo+"yes";
++++++++}++
++++}+
};

checkArr($b,+$a);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1128686|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>$a = [1 =&gt; 'funny', 3 =&gt; 'meshgaat', 15 =&gt; 'obi', 2 =&gt; 'OMER']; 

$b = 'omer';

function checkArr($x,$array)
{
 $arr = array_values($array);
 $arrlength = count($arr);
 $z = strtolower($x);

 for ($i = 0; $i &lt; $arrlength; $i++) {
 if ($z == strtolower($arr[$i])) {
 echo "yes";
 } 
 } 
};

checkArr($b, $a);
</code></pre>

blocks|key|1128761|text|$user_agent+=+'yandeX';
$bots+=+['Google','Yahoo','Yandex'];++++++++
++++++++
foreach($bots+as+$b){
+++++if(+stripos(+$user_agent,+$b+)+!==+false+)+return+$b;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1128762|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>$user_agent = 'yandeX';
$bots = ['Google','Yahoo','Yandex']; 
 
foreach($bots as $b){
 if( stripos( $user_agent, $b ) !== false ) return $b;
}
</code></pre>

Is it possible to do case-insensitive comparison when using the <code>in_array</code> function?

So with a source array like this:

<pre><code>$a= array(
 'one',
 'two',
 'three',
 'four'
);
</code></pre>

The following lookups would all return true:

<pre><code>in_array('one', $a);
in_array('two', $a);
in_array('ONE', $a);
in_array('fOUr', $a);
</code></pre>

What function or set of functions would do the same? I don't think <code>in_array</code> itself can do this.

PHP case-insensitive in_array function

在使用in_array函数时，是否可以进行不区分大小写的比较？因此，对于像这样的源数组：$a= array( 'one', 'two', 'three', 'four');以下查找将全部返回true：in_array('one', $a);in_array('two', $a);in_array('ONE', $a);in_array('fOUr', $a);什么函数或函数集会做同样的事情？我不认

问PHP不区分大小写的in_array函数
EN

回答 8

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问PHP不区分大小写的in_array函数
EN