PHP array_key_exists()Functions
Complete PHP Array Reference Manual
Examples
Check whether the key name "Volvo" exists in the array:
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
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Definition and Usage
The array_key_exists() function checks whether a specified key name exists in an array. If the key name exists, it returns true; if the key name does not exist, it returns false.
Tip:Remember, if you omit the key name when specifying an array, integer key names will be generated starting from 0 and incrementing by 1. (See Example 2)
Syntax
array_key_exists(key,array)
| Parameter | Description |
|---|---|
| key | Required. Specifies the key name. |
| array | Required. Specifies the array. |
Technical Details
| Return value: | Returns TRUE if the key name exists, and FALSE if the key name does not exist. |
|---|---|
| PHP Version: | 4.0.7+ |
More Examples
Example 1
Check whether the key name "Toyota" exists in the array:
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Toyota",$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
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Example 2
Check whether the integer key name "0" exists in the array:
$a=array("Volvo","BMW");
if (array_key_exists(0,$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
Run Example »
Other Extensions