The join() function merges array elements into one string with a separator between values. It is an alias of implode()—identical syntax, identical results. Many developers prefer join() because the name reads like plain English.
Join with glue.
Same function.
Comma, dash, newline.
“Join these items.”
Merge vs split.
Glue first, then array.
In PHP, join() is a built-in alias for implode(). Both accept a separator string and an array, then return a single string with the separator placed between each element. If you already know implode(), you already know join().
Pick one name and use it consistently in your project. PHP docs and most tutorials use implode(); JavaScript uses join(). In PHP, either works—they call the exact same internal function.
join() shares the same signatures as implode():
string join(string $separator, array $array)
// Optional: no separator (defaults to "")
string join(array $array)$separator — glue placed between elements (e.g. ", ", " - "). Optional in the one-argument form.$array — values to join. Array keys are ignored; only values are used.Returns a string with all array values joined by the separator. An empty array returns "".
join(", ", $arr)Readable list
implode(", ", $arr)Identical result
join($arr)No separator
explode(",", $str)String → array
Run these examples in PHP 7+. Each uses join() directly—replace with implode() anytime for the same output.
Join array items into a comma-separated string.
The classic join pattern from the PHP manual—readable and concise.
<?php
$fruits = ['apple', 'banana', 'orange'];
$result = join(', ', $fruits);
echo $result . "\n";
?>PHP inserts ", " between each fruit name. The function name join describes exactly what happens: join the array into one string.
Prove the alias relationship with a direct comparison.
<?php
$tags = ['php', 'mysql', 'html'];
$viaJoin = join(' | ', $tags);
$viaImplode = implode(' | ', $tags);
echo "join(): $viaJoin\n";
echo "implode(): $viaImplode\n";
echo "Same: " . ($viaJoin === $viaImplode ? "yes\n" : "no\n");
?>Both functions call the same underlying code. Choose based on readability and team convention—not behavior.
Paths, logs, and concatenation without a separator.
Combine parts with a slash separator (for simple cases; use proper path APIs for filesystem paths).
<?php
$segments = ['api', 'v1', 'users', '42'];
$url = join('/', $segments);
echo "URL: /$url\n";
?>Each segment is separated by /. For URL query strings, consider http_build_query() instead.
Join timestamp, level, and message with a pipe delimiter.
<?php
$parts = [date('Y-m-d H:i:s'), 'INFO', 'User logged in'];
$line = join(' | ', $parts);
echo $line . "\n";
?>Dynamic values (like date()) and static strings are joined in one readable call. The date in output varies at runtime.
Pass only the array to concatenate values with no glue between them.
<?php
$chars = ['H', 'e', 'l', 'l', 'o'];
$word = join($chars);
echo $word . "\n";
echo "Length: " . strlen($word) . "\n";
?>The one-argument form uses an empty separator, so characters are glued directly together—equivalent to implode('', $chars) or join('', $chars).
join() for familiar naming across languages.join() back together.join() WorksBoth names invoke the same PHP internal function with separator and array arguments.
Each array element is cast to string. Keys are skipped; order follows the array’s value order.
Glue is placed between each pair of values—never after the last one.
Ready to echo, log, store, or pass downstream.
join() is a strict alias of implode()—no behavioral difference.""; one element → that element alone.join() is faster than concatenating in a manual loop.The join() function is PHP’s readable name for joining array elements into a string. It is identical to implode()—use whichever name fits your codebase and team style.
Master separator-first syntax, pair with explode() when splitting and rejoining text, and pick one alias consistently across your project.
join() or implode() and stay consistentjoin($separator, $array) order in PHP 8+join() when code should read like Englishimplode() tutorial for deeper edge-case coveragejoin()Use these points whenever you join arrays into strings in PHP.
Identical function.
PurposePHP 8 syntax.
SyntaxPlain English.
StyleJoin vs split.
RelatedPick one alias.
Team ruleReview the full string function reference or continue with PHP interview programs.
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