PHP | array_change_key_case() Function
Last Updated :
08 Jan, 2018
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The array_change_key_case() function is an inbuilt function in PHP and is used to change case of all of the keys in a given array either to lower case or upper case.
Syntax:
array array_change_key_case(in_array, convert_case)Parameters: This function accepts two parameters out of which one is mandatory and the other is optional. The two parameters are described below:
- in_array (mandatory): This parameter refers to the array whose key's case is needed to be changed.
- convert_case (optional): This is an optional parameter and refers to the 'case' in which we need to convert the keys of the array. This can take two values, either CASE_UPPER or CASE_LOWER. CASE_UPPER value determines the uppercase and CASE_LOWER determines lowercase. If the convert_case parameter is not passed then it's default value is taken which is CASE_LOWER.
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Below program converts the case of keys to uppercase:
PHP <?php // PHP code to illustrate array_change_key_case() // Both the parameters are passed function change_case($in_array){ return(array_change_key_case($in_array, CASE_UPPER)); } // Driver Code $array = array("Aakash" => 90, "RagHav" => 80, "SiTa" => 95, "rohan" => 85, "RISHAV" => 70); print_r(change_case($array)); ?>
<?php
// PHP code to illustrate array_change_key_case()
// Both the parameters are passed
function change_case($in_array){
return(array_change_key_case($in_array, CASE_UPPER));
}
// Driver Code
$array = array("Aakash" => 90, "RagHav" => 80,
"SiTa" => 95, "rohan" => 85, "RISHAV" => 70);
print_r(change_case($array));
?>
Array ( [AAKASH] => 90 [RAGHAV] => 80 [SITA] => 95 [ROHAN] => 85 [RISHAV] => 70 )
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If we ignore the second parameter convert_case in the function array_change_key_case() then the keys will be converted to lowercase. Below program illustrates this:
PHP <?php // PHP code to illustrate array_change_key_case() // Second parameter is ignored function change_case($in_array){ return(array_change_key_case($in_array)); } // Driver Code $array = array("Aakash" => 90, "RagHav" => 80, "SiTa" => 95, "rohan" => 85, "RISHAV" => 70); print_r(change_case($array)); ?>
<?php
// PHP code to illustrate array_change_key_case()
// Second parameter is ignored
function change_case($in_array){
return(array_change_key_case($in_array));
}
// Driver Code
$array = array("Aakash" => 90, "RagHav" => 80,
"SiTa" => 95, "rohan" => 85, "RISHAV" => 70);
print_r(change_case($array));
?>
Array ( [aakash] => 90 [raghav] => 80 [sita] => 95 [rohan] => 85 [rishav] => 70 )
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If we don't pass an array to the function then PHP_Warning is popped up, but the program works and No Output is generated. Below program illustrates this
PHP <?php // PHP code to illustrate array_change_key_case() // NO parameter is passed function change_case($in_array){ return(array_change_key_case()); } // Driver Code $array = array("Aakash" => 90, "RagHav" => 80, "SiTa" => 95, "rohan" => 85, "RISHAV" => 70); print_r(change_case($array)); ?>
<?php
// PHP code to illustrate array_change_key_case()
// NO parameter is passed
function change_case($in_array){
return(array_change_key_case());
}
// Driver Code
$array = array("Aakash" => 90, "RagHav" => 80,
"SiTa" => 95, "rohan" => 85, "RISHAV" => 70);
print_r(change_case($array));
?>
No Output
Warning:PHP Warning: array_change_key_case() expects at least 1 parameter, 0 given in /home/7d540b2d77cbbfa46af4fb8798fb5e79.php on line 5