# PHP array_change_key_case() Function

PHP Array Reference

## Example

Change all keys in an array to uppercase:

<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
print_r(array_change_key_case($age,CASE_UPPER));
?>
Run example »

## Definition and Usage

The array_change_key_case() function changes all keys in an array to lowercase or uppercase.

## Syntax

array_change_key_case(array,case);

Parameter | Description
--- | ---
array | Required. Specifies the array to use

case

Optional. Possible values:

- CASE_LOWER - Default value. Changes the keys to lowercase
- CASE_UPPER - Changes the keys to uppercase

## Technical Details

Return Value: | Returns an array with its keys in lowercase or uppercase, or FALSE if array is not an array
PHP Version: | 4.2+

## More Examples

## Example 1

Change all keys in an array to lowercase:

<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
print_r(array_change_key_case($age,CASE_LOWER));
?>
Run example »

## Example 2

If two or more keys will be equal after running array_change_key_case() (e.g. "b" and "B"), the latest array will override the other:

<?php
$pets=array("a"=>"Cat","B"=>"Dog","c"=>"Horse","b"=>"Bird");
print_r(array_change_key_case($pets,CASE_UPPER));
?>
Run example »

PHP Array Reference

### WEB HOSTING

UK Reseller Hosting

### WEB BUILDING

FREE Website BUILDER Free HTML5 Templates

### W3SCHOOLS EXAMS

HTML, CSS, JavaScript, PHP, jQuery, XML, and ASP Certifications

### SHARE THIS PAGE

### Color Picker

### HTML/CSS

HTML Tutorial HTML5 Tutorial CSS Tutorial CSS3 Tutorial Bootstrap Tutorial

### JavaScript

JavaScript Tutorial jQuery Tutorial jQuery Mobile Tutorial AngularJS Tutorial AJAX Tutorial JSON Tutorial

### Graphics

Canvas Tutorial SVG Tutorial Google Maps Tutorial

### Server Side

SQL Tutorial PHP Tutorial ASP Tutorial ASP.NET Tutorial VBScript Tutorial AppML Tutorial

### Web

Web Building Web Statistics Web Certification

### XML

XML Tutorial DTD Tutorial Schema Tutorial XML DOM Tutorial XPath Tutorial XSLT Tutorial XQuery Tutorial XSL-FO Tutorial RSS Tutorial WSDL Tutorial

### HTML/CSS

HTML Tag Reference HTML Event Reference HTML Color Reference CSS 1,2,3 Reference Bootstrap Reference

### JavaScript

JavaScript Reference HTML DOM Reference jQuery Reference jQuery Mobile Reference Google Maps Reference

### Server Side

PHP Reference SQL Reference ASP Reference VBScript Reference Razor Reference ASP.NET Reference

### XML

XML DOM Reference XSLT Reference XSL-FO Reference XPath Reference XQuery Reference Schema Reference RSS Reference SVG Reference

### HTML Charsets

HTML Character Sets HTML ASCII HTML ANSI HTML Windows-1252 HTML ISO-8859-1 HTML Symbols HTML UTF-8

### HTML/CSS

HTML Examples CSS Examples

### Browser Scripting

JavaScript Examples HTML DOM Examples jQuery Examples jQuery Mobile Examples AngularJS Examples AJAX Examples

### Server Scripting

PHP Examples ASP Examples VBScript Examples Razor Examples .NET Examples

### XML Languages

XML Examples DTD Examples XML DOM Examples XSL Examples XSLT Examples XPath Examples XQuery Examples Schema Examples RSS Examples SVG Examples