Joining with implode()

PHP course · Beginner · Lesson 92/116

Learn to join an array into a string with a delimiter using implode().

Joining with implode()

To join an array into a single string, use implode(). It is called as implode($glue, $array); $glue is the separator placed between pieces, $array is the array to join. The result is a string.

Example: implode('-', ['2025', '01', '15']) returns '2025-01-15'. It is the reverse of explode(): you give an array and get a string.

Joining without a glue

The first argument of implode() is optional; if you omit it, the default glue is an empty string. So implode($array) joins all elements with nothing between them.

Example: implode(['a', 'b', 'c']) returns 'abc'. This is handy when you stitch token codes into a single cell or rebuild a string from its letters. For consistency, writing the glue explicitly is still a common choice.

Exercise Build a file path

Assign the array ['storage', 'uploads', 'avatar.png'] to $parts. Use implode() with the '/' glue to assign the joined string to $path. Then print it with echo $path;.

Show example solution

First assign the $parts array, then write $path = implode("/", $parts); and finally echo $path;
Example solution:
<?php
$parts = ["storage", "uploads", "avatar.png"];
$path = implode("/", $parts);
echo $path;

Test yourself

What does implode('-', ['2025', '01', '15']) return?
```
implode('-', ['2025', '01', '15'])
```
- 2025 01 15
- 2025-01-15
- 20250115
- ['2025-01-15']
Show answer

2025-01-15 — Correct. The three pieces join with '-': '2025-01-15'.

Join the tags

$tags = ['php', 'web', 'backend'];
$label = ____(', ', $tags);
echo $label;

Show answer

$tags = ['php', 'web', 'backend'];
$label = implode(', ', $tags);
echo $label;

Match each call to its result

implode('-', ['a','b'])

a-b
implode('', ['x','y','z'])

xyz
implode(', ', ['1','2'])

1, 2

Joining with implode()