ltrim()

The PHP ltrim() function removes whitespace (or other specified characters) from the left side — the beginning — of a string. The "l" stands for left. It is the counterpart of rtrim(), which strips from the right, and trim(), which strips from both ends.

ltrim() is most useful when you need to normalize input you don't fully control: leading spaces from form fields, leading zeros in identifiers, or leading separators left over after splitting or concatenating strings.

Syntax

ltrim(string $string, string $characters = " \n\r\t\v\0"): string

The function returns a new string; the original is never modified (PHP strings are passed by value).

The default character set

When you call ltrim() with one argument, it removes these characters from the left:

• " " (ordinary space)
• "\t" (tab)
• "\n" (line feed)
• "\r" (carriage return)
• "\0" (NUL byte)
• "\v" (vertical tab)

Trimming leading whitespace

The most common use is cleaning up leading whitespace:

Output:

[Hello World!   ]

Notice that the trailing spaces remain — ltrim() only touches the left side. The [ and ] brackets are added just to make the boundaries visible in the output.

Trimming specific characters

Pass a second argument to remove a custom set of characters instead of whitespace. A classic case is stripping leading zeros:

<?php
echo ltrim("0042", "0");      // 42
echo "\n";
echo ltrim("xxxHello", "x");  // Hello
?>

Output:

42
Hello

The $characters argument is a set, not a substring. Every listed character is removed independently, so ltrim($line, ".,") strips any combination of leading dots and commas:

<?php
$line = "...,.,Hello, World";
echo ltrim($line, ".,");  // Hello, World
?>

Output:

Hello, World

It stops at the first character that is not in the set (H here), leaving the inner , in Hello, World untouched.

Common gotchas

• It is not a substring removal. ltrim("hello", "he") removes both h and e characters, returning "llo" — it does not look for the literal prefix "he". To strip a known prefix, use str_replace() on the first occurrence or substr().
• Byte-based, not Unicode-aware. ltrim() works on bytes, so it can corrupt multibyte UTF-8 characters if you list them in $characters. For ASCII it is perfectly safe; for trimming multibyte characters, use a preg_replace() pattern with the u modifier.
• It returns a copy. Assign the result back if you want to keep it: $s = ltrim($s);.

When to use which trim

For a broader tour of PHP string handling, see PHP Strings.

Practice