PHP Whitespace

Whitespace means spaces, tabs and line breaks. In PHP code, most whitespace does not matter. These two programs do exactly the same thing:

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<?php
$a=1;$b=2;echo $a+$b;

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<?php
$a = 1;
$b = 2;

echo $a + $b;

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The second version is much easier to read. Use whitespace for people, not for PHP.

Where whitespace does matter

You cannot put a space in the middle of a name.

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<?php
$my name = "Ravi"; // wrong: a space splits the name in two
$my_name = "Ravi"; // correct

Whitespace inside a string is part of the string.

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<?php
echo "a   b";

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a   b

Indentation

PHP does not need indentation, but you should always use it. The common style uses 4 spaces per level.

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<?php
$age = 20;

if ($age >= 18) {
    echo "Adult";
} else {
    echo "Minor";
}

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Adult

Whitespace outside PHP tags is output

Anything outside <?php ... ?> is sent to the browser. A space or blank line before the opening tag, or after a closing tag, becomes part of the page.

That is why a PHP-only file should start with <?php on the very first line and should not have a closing ?> tag. PHP Tags explains the reason.