How to determine whether an array contains a certain value in php

In PHP, determining whether an array contains a certain value is a common task. Common methods include using the in_array() function, using the array_search() function, or using the in_array() function combined with the strict parameter.

1. Use the in_array() function

The in_array() function can check whether a specified value exists in an array. The function returns true if the value being looked up exists in the array, false otherwise.

Syntax:

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

Among them, $needle represents the value to be found, $ haystack represents the target array, and $strict represents whether strict comparison mode is enabled.

Example:

$arr ​​= array(1, 2, 3, 'hello');
if(in_array('hello', $arr)) {

echo '数组中存在需要查找的值';

} else {

echo '数组中不存在需要查找的值';

}

2. Use array_search() function

array_search() function can find the specified value in an array Key name. If the value is found, the key name is returned; if not found, false is returned.

Syntax:

mixed array_search ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

Among them, $needle represents the value to be found, $ haystack represents the target array, and $strict represents whether strict comparison mode is enabled.

Example:

$arr ​​= array(1, 2, 3, 'hello');
$key = array_search('hello', $arr);
if ($key !== false) {

echo '数组中存在需要查找的值，键名为' . $key;

} else {

echo '数组中不存在需要查找的值';

}

3. Use the in_array() function with the strict parameter

The in_array() function combined with the strict parameter can find the specified value in the array and enable strict comparison mode.

Syntax:

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

Among them, $needle represents the value to be found, $ haystack represents the target array, and $strict represents whether strict comparison mode is enabled.

Example:

$arr ​​= array(1, 2, 3, 'hello');
if(in_array('1', $arr, true)) {

echo '数组中存在需要查找的值，并且启用了严格比较模式';

} else {

echo '数组中不存在需要查找的值';

}

To sum up, the above three methods can be used to determine whether an array contains a certain value in PHP. In actual development, you can choose which method to use based on the situation and personal habits.

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