How to determine whether a specified string belongs to an array in php

Two methods: 1. Use is_array(), the syntax is "in_array("value",$arr,TRUE)", if it belongs, TRUE will be returned. 2. Use array_search(), the syntax is "array_search("value",$arr,true)", if it belongs, the corresponding key name will be returned.

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

How to determine the specified php Whether the string belongs to an array

php determines whether the specified string belongs to an array, which is to determine whether the specified string is in the array. Here are some ways to judge.

Method 1. Use the is_array() function to determine whether the

in_array() function searches whether the specified value exists in the array.

• Just set the first parameter of the is_array() function to the specified string.

• Returns TRUE if the value is found in the array, otherwise returns FALSE.

Example: Determine whether the string "4" is in the array

<?php
header("Content-type:text/html;charset=utf-8");
$arr = array(1,"bb",3,"aa",4,"aA","BB");
var_dump($arr);
if(in_array("4",$arr,TRUE)){
	echo "指定值在二维数组中";
}else{
	echo "指定值不在二维数组中";
}
?>

It can be seen that there is a value in the array 4, but it is a numeric value, not a string, so the string "4" is not in the array

Explanation:

is_array() function has an optional third parameter. If this parameter Set to TRUE to check whether the type of the searched data and the value of the array are the same.

Method 2: Use array_search() function

array_search() function searches for a key value in the array and returns the corresponding key name.

If the specified key value is found in the array, return the corresponding key name, otherwise return FALSE. If a key value is found more than once in the array, the key name matching the first found key value is returned.

Example: Determine whether the string "1" is in the array

<?php
header("Content-type:text/html;charset=utf-8");
$arr = array(1,"bb",3,"aa",4,"aA","BB");
var_dump($arr);
if(array_search("1",$arr,true)){
	echo "指定值在二维数组中";
}else{
	echo "指定值不在二维数组中";
}

?>

It can be seen that there is a value 1 in the array, but it is a numerical value , not a string, so the string "1" is not in the array.

Note:

array_search() function also has an optional third parameter. If this parameter is set to TRUE, The function searches the array for elements with the same data type and value

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