Here is an array that has some duplicate values:

The following code will remove all duplicate values from an array using PHP array_unique() function:

The result array will have the values like the below:

Now, we will show you how to remove duplicate values with case/space insensitively from an array in PHP.

If an array has duplicate values with a combination of upper/lower/word cases, the values need to be converted in the same latter case before applying the array_unique(). Also, we need to remove the space from values before duplicate comparison.

The following code snippet removes duplicate values from the array with case and space insensitively using PHP array_map() and array_unique() functions.

• Remove space from all strings in an array using the trim callback method with the array_map() function.
• Convert array values to lowercase using the strtolower callback method with the array_map() function.
• Use array_unique() function to remove duplicate values from array with PHP.
• Finally, use the array_intersect_key() function to return the combination of the result array.

Example:
Array values with lowercase, uppercase, and blank space:

Result array will be: