PHP str_pad() Function: Syntax, Parameters, Return Value, and Usage Examples

str_pad() pads a string to a specified length using another string.

Signature:

string str_pad ( string $input , int $pad_length [, string $pad_string = " " [, int $pad_type = STR_PAD_RIGHT ]] )

Description: The function returns the input string padded on the left, right, or both sides to reach the desired length. If $pad_string is omitted, spaces are used; otherwise the provided string is used. If $pad_length is negative or less than or equal to the length of $input , no padding occurs.

Parameters:

$input – the input string.

$pad_length – the target length; negative values result in no padding.

$pad_string – the string used for padding; if its length does not evenly divide the required padding, it may be truncated.

$pad_type – optional; can be STR_PAD_RIGHT , STR_PAD_LEFT , or STR_PAD_BOTH . Default is STR_PAD_RIGHT .

Return value: The padded string.

Examples:

<?php
$input = "Alien";
// Right padding (default) to length 10
echo str_pad($input, 10); // outputs "Alien     "

// Left padding with custom string "-=" to length 10
echo str_pad($input, 10, "-=", STR_PAD_LEFT); // outputs "-=-=-Alien"

// Both-side padding with "_" to length 10
echo str_pad($input, 10, "_", STR_PAD_BOTH); // outputs "__Alien___"

// Padding to length 6 with "___" (right padding by default)
echo str_pad($input, 6, "___"); // outputs "Alien_"