PHP String Operators: Concatenation with . and .=

PHP has only two string operators. They both join strings, which is called concatenation.

Operator	Name	Example
`.`	Concatenation	`"Hello" . " world"`
`.=`	Concatenation assignment	`$text .= " more"`

index.php

PHP

<?php
$first = "Ada";
$last = "Lovelace";

$full = $first . " " . $last;
echo $full;

Output

OUTPUT

Ada Lovelace

Adding to a string

index.php

PHP

<?php
$message = "Order placed.";
$message .= " We will email you.";
$message .= " Thank you!";

echo $message;

Output

OUTPUT

Order placed. We will email you. Thank you!

Numbers become text

When you join a number with a string, PHP converts the number to text for you.

index.php

PHP

1
2
3

<?php
$items = 3;
echo "You have " . $items . " items.";

Output

OUTPUT

You have 3 items.

A dot next to a number

Be careful with spaces around a dot and a number. 1 . 2 and 1.2 are different things.

index.php

PHP

1
2
3

<?php
echo 1 . 2 . "\n";   // concatenation: "12"
echo 1.2 . "\n";     // the number 1.2

Output

OUTPUT

1
2

12
1.2

Mixing + and .

In PHP 8, + is calculated before .. In older versions, they had the same priority, which gave confusing results. Brackets make it clear in any version.

index.php

PHP

1
2

<?php
echo "Total: " . (2 + 3);

Output

OUTPUT

Total: 5

Or use interpolation

For short text, putting variables inside double quotes is often neater than many dots. See String Interpolation.

index.php

PHP

<?php
$name = "Ada";
$age = 36;

echo "Name: " . $name . ", age: " . $age . "\n";
echo "Name: $name, age: $age";

Output

OUTPUT

1
2

Name: Ada, age: 36
Name: Ada, age: 36

warning

Using + to join strings

In JavaScript "a" + "b" joins. In PHP, + is only for numbers, and "a" + "b" throws an error. Use the dot.