Example
Check if the key "Volvo" exists in an array:
<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
?>
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Definition and Usage
The array_key_exists() function checks an array for a specified key, and returns true if the key exists and false if the key does not exist.
Tip: Remember that if you skip the key when you specify an array, an integer key is generated, starting at 0 and increases by 1 for each value. (See example 2)
Syntax
array_key_exists(key,array)
| Parameter | Description |
|---|---|
| key | Required. Specifies the key |
| array | Required. Specifies an array |
Technical Details
| Return Value: | Returns TRUE if the key exists and FALSE if the key does not exist |
|---|---|
| PHP Version: | 4.0.7+ |
More Examples
Example 1
Check if the key "Toyota" exists in an array:
<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (key_exists("Toyota",$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
?>
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Example 2
Check if the integer key "0" exists in an array:
<?php
$a=array("Volvo","BMW");
if (array_key_exists(0,$a))
{
echo "Key exists!";
}
else
{
echo "Key does not exist!";
}
?>
Run example »
< PHP Array Reference