(PHP 4, PHP 5, PHP 7, PHP 8)
implode — Join array elements with a string
Alternative signature (not supported with named arguments):
Legacy signature (deprecated as of PHP 7.4.0, removed as of PHP 8.0.0):
Join array elements with a separator string.
separatorOptional. Defaults to an empty string.
arrayThe array of strings to implode.
Returns a string containing a string representation of all the array elements in the same order, with the separator string between each element.
| Version | Description |
|---|---|
| 8.0.0 | Passing the separator after the array is no longer supported. |
| 7.4.0 | Passing the separator after the array (i.e. using the legacy signature) has been deprecated. |
Example #1 implode() example
<?php
$array = ['lastname', 'email', 'phone'];
var_dump(implode(",", $array)); // string(20) "lastname,email,phone"
// Empty string when using an empty array:
var_dump(implode('hello', [])); // string(0) ""
// The separator is optional:
var_dump(implode(['a', 'b', 'c'])); // string(3) "abc"
?>Note: This function is binary-safe.
it should be noted that an array with one or no elements works fine. for example: <?php $a1 = array("1","2","3"); $a2 = array("a"); $a3 = array(); echo "a1 is: '".implode("','",$a1)."'<br>"; echo "a2 is: '".implode("','",$a2)."'<br>"; echo "a3 is: '".implode("','",$a3)."'<br>"; ?> will produce: =========== a1 is: '1','2','3' a2 is: 'a' a3 is: ''It's not obvious from the samples, if/how associative arrays are handled. The "implode" function acts on the array "values", disregarding any keys: <?php declare(strict_types=1); $a = array( 'one','two','three' ); $b = array( '1st' => 'four', 'five', '3rd' => 'six' ); echo implode( ',', $a ),'/', implode( ',', $b ); ?> outputs: one,two,three/four,five,sixCan also be used for building tags or complex lists, like the following: <?php $elements = array('a', 'b', 'c'); echo "<ul><li>" . implode("</li><li>", $elements) . "</li></ul>"; ?> This is just an example, you can create a lot more just finding the right glue! ;)If you want to implode an array of booleans, you will get a strange result: <?php var_dump(implode('',array(true, true, false, false, true))); ?> Output: string(3) "111" TRUE became "1", FALSE became nothing.It might be worthwhile noting that the array supplied to implode() can contain objects, provided the objects implement the __toString() method. Example: <?php class Foo { protected $title; public function __construct($title) { $this->title = $title; } public function __toString() { return $this->title; } } $array = [ new Foo('foo'), new Foo('bar'), new Foo('qux') ]; echo implode('; ', $array); ?> will output: foo; bar; quxIf you want to implode an array as key-value pairs, this method comes in handy. The third parameter is the symbol to be used between key and value. <?php function mapped_implode($glue, $array, $symbol = '=') { return implode($glue, array_map( function($k, $v) use($symbol) { return $k . $symbol . $v; }, array_keys($array), array_values($array) ) ); } $arr = [ 'x'=> 5, 'y'=> 7, 'z'=> 99, 'hello' => 'World', 7 => 'Foo', ]; echo mapped_implode(', ', $arr, ' is '); // output: x is 5, y is 7, z is 99, hello is World, 7 is Foo ?>It may be worth noting that if you accidentally call implode on a string rather than an array, you do NOT get your string back, you get NULL: <?php var_dump(implode(':', 'xxxxx')); ?> returns NULL This threw me for a little while.Even handier if you use the following: <?php $id_nums = array(1,6,12,18,24); $id_nums = implode(", ", $id_nums); $sqlquery = "Select name,email,phone from usertable where user_id IN ($id_nums)"; // $sqlquery becomes "Select name,email,phone from usertable where user_id IN (1,6,12,18,24)" ?> Be sure to escape/sanitize/use prepared statements if you get the ids from users.