How to detect whether an array has a certain key value in php

Two methods: 1. Use the "array_search(specified key value, $arr)" statement. If the key name is returned, the key value is specified. If FALSE is returned, the key value is not specified. 2. Use the "array_keys($arr, key value)" statement. If the returned key array is empty, there is no key value specified, otherwise there is a key value.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php detects whether the array There are two methods for a certain key value

Method 1: Use the array_search() function

array_search() function to search for a certain key value in the array key value and returns the corresponding key name. Otherwise returns FALSE if there is no value.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array(1,0,&#39;4&#39;,2,3,4);
if(array_search(4,$arr)!="FALSE"){
	echo "有指定键值";
}else{
	echo "没有指定键值";
}
?>

2. Use array_keys() function

array_keys() function can also search for key values ​​and return the corresponding key name.

But array_keys() will return the obtained array key name in the form of an array. If no value is specified, the returned array is an empty array.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr=array(1,0,&#39;4&#39;,2,3,4);
$key=array_keys($arr,6);
var_dump($key);
if($key!=[]){
	echo "有指定键值";
}else{
	echo "没有指定键值";
}
?>

Modify it and search for 2

$key=array_keys($arr,2);

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