php determines whether text is in array

In PHP, sometimes we need to determine whether a text is in an array so that we can perform corresponding operations in subsequent processing.

At this time, we can use the PHP function in_array() to solve this problem. The in_array() function is used to check whether a value exists in an array. It accepts two parameters: the value to be judged and the array to be checked.

The syntax is as follows:

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

Among them, value represents the value to be found; array Indicates the array being searched; strict indicates whether to use strict data types when comparing (default is FALSE, indicating that strict type comparison is not used).

Returns true if value is found, false if not in the array.

The following is an example to illustrate how to use the in_array() function:

<?php
$arr = array("apple", "banana", "pear");
if (in_array("apple", $arr)) {
    echo "在数组中";
} else {
    echo "不在数组中";
}

The above code outputs "in the array" because the value "apple" is indeed in the $arr array.

If we look for a value that is not present in the array, for example "orange":

<?php
$arr = array("apple", "banana", "pear");
if (in_array("orange", $arr)) {
    echo "在数组中";
} else {
    echo "不在数组中";
}

The output will be "not in array".

In actual development, we may need to perform strict comparison of data types to avoid judgment errors caused by type errors. For example, we need to determine whether the integer value is in an array:

<?php
$arr = array(1, 2, 3);
if (in_array("2", $arr, true)) {
    echo "在数组中";
} else {
    echo "不在数组中";
}

Due to the use of strict type comparison, the string "2" is not equal to the integer 2, so the in_array() function returns " Not in array".

It should be noted that the in_array() function can only check the value in the array, but cannot determine whether the key name exists in the array. If you need to determine whether a key exists, you can use the array_key_exists() function.

To summarize, in PHP you can use the in_array() function to determine whether a text is in an array. The syntax is very simple, especially the third parameter can be used for strict data type comparison.

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