PHP String str_pad() Function

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The PHP String str_pad() function is used to return the string with padding on the left, right, or both sides equal to the given padding length. If the optional parameter pad_string does not exist, the string is padded with spaces; otherwise, it is padded with pad_string characters until the limit is reached.

Syntax

Below is the syntax of the PHP String str_pad() function −

string str_pad(
   string $string,
   int $length,
   string $pad_string = " ",
   int $pad_type = STR_PAD_RIGHT
)

Parameters

Here are the parameters of the str_pad() function −

• $string − (Required) It is the input string to be padded.

• $length − (Required) It is the final length of the output string after padding.

• $pad_string − (Optional) It is the string to pad the input string with. Defaults to a single space (" ").

• $pad_type − (Optional) It specifies where the padding should be applied. Options are: STR_PAD_RIGHT (default, Pads to the right), STR_PAD_LEFT (Pads to the left), STR_PAD_BOTH (Pads equally on both sides).

Return Value

The str_pad() function returns the padded string.

PHP Version

First introduced in core PHP 4.0.1, the str_pad() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

This example demonstrates how to use the PHP String str_pad() function with its default values to pad a string to a specified length.

In our example the string "Hello" is padded with spaces to make the total length 10. The default padding is to the right of the string.

<?php
   // Input string
   $string = "Hello";

   // Padding the string
   $padded = str_pad($string, 10);

   echo $padded; 
?>

Output

Here is the outcome of the following code −

Hello     

Example 2

In the below PHP code we will use the str_pad() function and pads a string with a custom character instead of spaces.

<?php
   // Input string
   $string = "World";

   // Padding the string with '*' 
   $padded = str_pad($string, 12, "*");

   echo $padded; 
?> 

Output

This will generate the below output −

World*******

Example 3

Now the below code uses str_pad() function with the STR_PAD_LEFT option to pad the string on the left of the given string.

<?php
   // Input string
   $string = "PHP";

   // Padding the string on the left
   $padded = str_pad($string, 8, "-", STR_PAD_LEFT);

   echo $padded; 
?> 

Output

This will create the below output −

-----PHP

Example 4

This program uses str_pad() function with the STR_PAD_BOTH option to add padding on both sides for centering the string.

<?php
   // Input string
   $string = "Center";

   // Padding the string on both sides 
   $padded = str_pad($string, 12, "=", STR_PAD_BOTH);

   echo $padded; 
?> 

Output

Following is the output of the above code −

==Center===