How to determine if a value exists in an array in php

In PHP, to find whether an element exists in an array, you can use the in_array() function. The function of this function is to determine whether a value exists in an array and return a bool value, that is, it returns true if it exists, and false if it does not exist.

The following is the syntax of the in_array() function:

in_array( $value, $array [, $strict ] )

where $value represents the element to be found, $ Array represents the array to be searched. $strict is an optional parameter. The default is false, which means using non-strict (ie relaxed) mode to search. If you want to use strict mode for searching, you can set $strict to true.

For example, suppose there is an array $arr, which contains several elements. Now we want to find whether the element "apple" exists in the array, you can use the following code:

if (in_array('apple', $arr)){

echo '存在';

} else {

echo '不存在';

}

The result output by the above code depends on whether the $arr array contains elements. Depends on "apple".

In addition to the in_array() function, you can also use the array_search() function to find elements in an array. The function of this function is to search for the specified value in the array. If it is found, it returns the key name corresponding to the value. If it is not found, it returns false.

The following is the syntax of the array_search() function:

array_search( $needle, $haystack [, $strict ] )

where $needle represents the element to be found, $ haystack represents the array to be searched, $strict is an optional parameter, and has the same meaning as the $strict parameter in the in_array() function.

For example, suppose there is an array $arr, which contains several elements. Now we want to find the index position of the element "apple" in the array, you can use the following code:

$index = array_search('apple', $arr);
if ($index !== false){

echo '存在，索引位置为'.$index;

} else {

echo '不存在';

}

The result output by the above code depends on whether the element "apple" is included in the $arr array.

It should be noted that when using the array_search() function, if the value corresponding to the found element is 0, the returned index position is also 0. At this time, it is necessary to determine whether the return value is false, because 0 is also stands for false. You can use the congruent (i.e. "===") comparison operator to determine whether the return value is false (i.e. strictly not equal to false).

The above is how to find whether an element exists in an array in PHP. Which method to choose depends mainly on the actual situation and personal preference.

The above is the detailed content of How to determine if a value exists in an array in php. For more information, please follow other related articles on the PHP Chinese website!