PHP determines whether characters are contained in an array

In PHP development, we often need to process and judge strings. When determining whether a string contains a certain character, we can use the in_array() function in PHP.

in_array() function is used to determine whether a value exists in an array. The syntax of this function is as follows:

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

Parameter description:

• value: the value to be judged
• array: the array to be searched
• strict : Optional parameter, whether to use strict mode. If strict is TRUE, the types are also checked for equality. Default is FALSE.

Next we will show how to use the in_array() function to determine whether a string is contained in an array.

Suppose we have an array $fruits:

$fruits = array("apple", "banana", "orange", "mango", "kiwi");

Now, we want to determine whether it contains the string "banana", you can use the following code:

if (in_array("banana", $fruits)) {
    echo "数组中包含 'banana'。";
} else {
    echo "数组中不包含 'banana'。";
}

If the fruits are in the array , the script will output: The array contains 'banana'.

If the fruit is not in the array, the script will output: The array does not contain 'banana'.

In addition to determining whether the string is contained in the array, we can also use the in_array() function to determine whether numbers, Boolean types, arrays, etc. exist in the array. Here is some sample code:

// 判断数字是否在数组中
$numbers = array(1, 2, 3, 4, 5);
if (in_array(3, $numbers)) {
    echo "数字 3 在数组中。";
} else {
    echo "数字 3 不在数组中。";
}

// 判断布尔型是否在数组中
$bools = array(true, false);
if (in_array(false, $bools)) {
    echo "布尔型 false 在数组中。";
} else {
    echo "布尔型 false 不在数组中。";
}

// 判断数组是否在数组中
$arrays = array(
    array("apple", "banana"),
    array("orange", "mango")
);
$search_array = array("orange", "mango");
if (in_array($search_array, $arrays)) {
    echo "数组 ['orange', 'mango'] 在主数组中。";
} else {
    echo "数组 ['orange', 'mango'] 不在主数组中。";
}

To summarize, using the in_array() function in PHP can quickly and easily determine whether strings, numbers, booleans, and arrays exist in arrays. When judging strings, be sure to pay attention to capitalization to avoid misjudgment.

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