PHP trim is an inbuilt function in PHP. It removes whitespaces (or other characters) from both the left and right sides of a string. In this article, we will discuss the PHP trim Function. Also, we will discuss a few examples of using it.
To remove characters only from left or right, you can use the following functions:
- PHP ltrim Function: Remove Characters only from Left Side of String.
- PHP rtrim Function: Remove Characters only from Right Side of String.
Syntax
trim($string, $characterList)
Parameters
The PHP trim Function expects two parameters. However, only one parameter is mandatory and the other is optional.
- $string: The first parameter to the function is the string to operate on. It is a mandatory parameter.
- $characterList: The second parameter to the function is an optional parameter. It specifies the character list to remove from the string. By default, the function removes all the following characters:
- “\0” – NULL
- “\t” – tab
- “\n” – new line
- “\x0B” – vertical tab
- “\r” – carriage return
- ” ” – ordinary white space
Return Value
The trim function in PHP returns the string after removing whitespaces and all other predefined characters from both ends.
Note: The function returns an empty string when the argument is a null variable.

Examples
Let’s discuss a few examples of using the function.
Example 1: Removing Whitespaces
For instance, consider a simple string containing whitespaces on both ends.
<?php $string = ' Simple string '; $trimmedString = trim($string); var_dump($trimmedString); ?>
In the above example, the function removes whitespaces from both ends of the string.
OUTPUT: string(15) "Simple string"
Example 2: Specifying Characters to Remove
Also, we can specify characters to remove by passing the second parameter.
<?php $str = "Hello World!"; echo $str; //Remove "He" in "Hello" and "d!" in "World" echo trim($str,"Hed!"); ?>
The above example will print the following:
OUTPUT: Hello World! llo Worl
Example 3: Removing Whitespaces from Array of Strings
Similarly, you can remove whitespaces from an array of strings using PHP array_map. We can pass the trim function as callback in array_map function.
<?php $fruit = array('apple','banana ', ' mango '); $trimmedArray = array_map('trim', $fruit); var_dump($trimmedArray); ?>
The above example will print the following:
OUTPUT: array(3) { [0]=> string(5) "apple" [1]=> string(6) "banana" [2]=> string(5) "mango" }
Conclusion
In conclusion, we discussed the PHP trim Function. You can read more about it on PHP Official Documentation. Additionally, you can learn about more PHP String Functions on Concatly.

Vishesh is currently working as an Intermediate Software Engineer with Orion Health, New Zealand. He graduated with a Masters in Information Technology from the University of Auckland in 2021. With more than 4 years of work experience, his expertise includes Java, Python, Machine Learning, PHP, Databases, Design and Architecture.