The pre_category_nicename filter allows you to modify the category nicename before it is sanitized in WordPress.
Use the ‘pre_$taxonomy_$field’ hook instead.
Usage
add_filter('pre_category_nicename', 'your_custom_function');
function your_custom_function($value) {
// your custom code here
return $value;
}
Parameters
$value(string) – The category nicename to be filtered.
More information
See WordPress Developer Resources: pre_category_nicename
Examples
Append a prefix to category nicename
This example appends a prefix “my-” to the category nicename.
add_filter('pre_category_nicename', 'add_prefix_to_nicename');
function add_prefix_to_nicename($value) {
$value = 'my-' . $value;
return $value;
}
Convert category nicename to uppercase
This example converts the category nicename to uppercase.
add_filter('pre_category_nicename', 'uppercase_nicename');
function uppercase_nicename($value) {
$value = strtoupper($value);
return $value;
}
Replace spaces with underscores in category nicename
This example replaces spaces with underscores in the category nicename.
add_filter('pre_category_nicename', 'replace_spaces_with_underscores');
function replace_spaces_with_underscores($value) {
$value = str_replace(' ', '_', $value);
return $value;
}
Remove non-alphanumeric characters from category nicename
This example removes non-alphanumeric characters from the category nicename.
add_filter('pre_category_nicename', 'remove_non_alphanumeric');
function remove_non_alphanumeric($value) {
$value = preg_replace("/[^a-zA-Z0-9]+/", "", $value);
return $value;
}
Add a suffix to category nicename
This example appends a suffix “-cat” to the category nicename.
add_filter('pre_category_nicename', 'add_suffix_to_nicename');
function add_suffix_to_nicename($value) {
$value = $value . '-cat';
return $value;
}