How to determine whether a specified value is an array key in PHP

In PHP, you can use the array_key_exists() function to determine whether the specified value is an array key. This function can check whether the specified key exists in an array; the syntax is "array_key_exists(key,array)" .

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

In php, you can use the array_key_exists() function To determine whether the specified value is an array key.

array_key_exists() function checks whether the specified key exists in an array. If the key exists, it returns true. If the key does not exist, it returns false.

Syntax:

array_key_exists(key,array)

• key Required. Specifies the key name.

• array Required. Specifies an array.

Example: Determine whether the specified value Volvo is an array key name

"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
{
    echo "指定值Volvo 是数组键名";
}
else
{
    echo "指定值Volvo 不是数组键名";
}
?>

Output result:

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