PHP: Escape sequences

Suppose we want to print the text below on two lines:

- Are you hungry?
- Aaaarrrgh!

If we simply pass this text to print_r(), PHP will print everything on a single line. Technically, we could write two consecutive print_r() calls, but let's imagine we want to do it with a single one:

<?php

print_r("- Are you hungry?- Aaaarrrgh!");
// => - Are you hungry?- Aaaarrrgh!

For each of them to start on a new line, we need to add a line break, that is, "press Enter". In programming, this is done by adding special characters, in this case \n. Yes, that's not a typo. Even though we see two characters here, from PHP's perspective this is a single character:

<?php

print_r("- Are you hungry?\n- Aaaarrrgh!");

The result will be:

- Are you hungry?
- Aaaarrrgh!

What is \n?

\n is an escape sequence (sometimes called an "escaped sequence"). It denotes a line break, but isn't displayed directly. You won't see \n in the program's output, since it only affects the placement of the text.

In text editors, pressing Enter adds the invisible LF (Line Feed) character. That's exactly what \n means. Sometimes you can see such characters if you enable the display of special characters:

- Привет!¶
- О, привет!¶
- Как дела?

Printers, editors, and the PHP interpreter understand \n as a command to start the text on a new line.

An important feature of PHP: escape sequences like \n only work inside double quotes. In single quotes, \n is just two ordinary characters, \ and n:

<?php

print_r("Hello\nWorld");
// Hello
// World

print_r('Hello\nWorld');
// => Hello\nWorld

Examples of using \n

Here's how PHP handles the escape sequence \n:

In code      "Hello\nWorld"
                   ↓
On screen    Hello
             World

The position of \n changes the resulting output:

<?php

print_r("Hello\nWorld");
// Hello
// World

print_r("Hello \nWorld");
// Hello
// World  (there is a space at the end of the first line)

print_r("Hello\n World");
// Hello
//  World  (there is a space at the start of the second line)

print_r("Hello\n\nWorld");
// Hello
//
// World  (an empty line between them)

Spaces before or after \n are also taken into account. PHP treats them as ordinary characters and displays them in the output.

You can also insert \n into any part of a string — before, after, or even use it on its own:

<?php

print_r("First line\n");
print_r("\n"); // Just an empty line
print_r("Second line");

The result will be:

First line

Second line

How to print the \n character itself

\n in PHP is an escape sequence. It controls the placement of text and isn't displayed on the screen as ordinary characters. If you need to print exactly the characters \ and n, rather than a line break, they need to be escaped. To do this, you add another slash before the backslash:

<?php

print_r("Hello\\nWorld");
// => Hello\nWorld

// If you forget to add the second slash
print_r("Hello\nWorld");
// Hello
// World

In this case, PHP understands \\ as an ordinary backslash and shows the string without a line break.

Other escape sequences

Besides \n, PHP has other escape sequences:

• \t denotes a tab (the equivalent of the Tab key)
• \r denotes a carriage return (used in Windows, but rarely applied in PHP code)
• In programming, \n is the most commonly used one, it's enough for most tasks

Important details

• \n is a single character, even though it's written in code as two (\ and n)
• Escape sequences in PHP only work inside double quotes
• On Windows, the combination \r\n is used by default, but in cross-platform development it's customary to use only \n to avoid problems when moving code between systems. That's why it's worth configuring your editor to use \n

You are writing a program that shows the user a tip about how to split text into lines. Print the tip with a single print_r() call:

Для разделения строк используйте "\n"
Пример: print_r("строка1\nстрока2")

Note: the \n in the first line is literal text, not a line break.