International PHP Conference Munich 2024

implode

(PHP 4, PHP 5, PHP 7, PHP 8)

implodeUnisce gli elementi di una matrice in una stringa

Descrizione

implode(string $glue, array $pieces): string

Restituisce una stringa contenente tutti gli elementi di una matrice nel medesimo ordine, inserendo il parametro glue tra un elemento e l'altro.

Example #1 Esempio di uso di implode()

<?php

$array
= array('lastname', 'email', 'phone');
$comma_separated = implode(",", $array);

echo
$comma_separated; // lastname,email,phone

?>

Nota:

La funzione implode(), per ragioni storiche, può accettare i propri parametri in entrambi gli ordini. Tuttavia per mantenere la consistenza con explode(), ed avere meno confusione, utilizzare i parametri nell'ordine documentato.

Nota:

Dal PHP 4.3.0, il parametro glue di implode() è opzionale e come default utilizza una stringa vuota (''). Questo non è l'utilizzo preferenziale di implode(). Si suggerisce di utilizzare sempre il secondo parametro per compatibilità con le vecchie versioni.

Nota: Questa funzione è binary-safe (gestisce correttamente i file binari)

Vedere anche explode() e split().

add a note

User Contributed Notes 14 notes

up
355
houston_roadrunner at yahoo dot com
15 years ago
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: ''
up
90
ASchmidt at Anamera dot net
5 years ago
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,six
up
105
omar dot ajoue at kekanto dot com
11 years ago
Can 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! ;)
up
26
Felix Rauch
7 years ago
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; qux
up
47
alexey dot klimko at gmail dot com
12 years ago
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.
up
10
Honk der Hase
4 years ago
If 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

?>
up
3
biziclop
3 years ago
Sometimes it's necessary to add a string not just between the items, but before or after too, and proper handling of zero items is also needed.
In this case, simply prepending/appending the separator next to implode() is not enough, so I made this little helper function.

<?php

function wrap_implode( $array, $before = '', $after = '', $separator = '' ){
if( !
$array ) return '';
return
$before . implode("{$after}{$separator}{$before}", $array ) . $after;
}

echo
wrap_implode(['path','to','file.php'], '/');
// "/path/to/file.php"

$pattern = '#'. wrap_implode([4,2,2], '\d{', '}', '[-.]') .'#';
echo
$pattern, "\n"; // #\d{4}[-.]\d{2}[-.]\d{2}#
echo preg_replace( $pattern, '[REDACTED]', 'The UFO appeared between 2012-12-24 and 2013.01.06 every night.');
// 'The UFO appeared between [REDACTED] and [REDACTED] every night.

echo wrap_implode(['line','by','line'], '<b>', '</b>', '<br> ');
// <b>line</b><br> <b>by</b><br> <b>line</b>

echo wrap_implode( ['<a href="">Menu Item 1</a>', '<a href="">Menu Item 2</a>',],
"<li>", "</li>\n",
"<li> | </li>\n",
);
/*
<li><a href="">Link1</a></li>
<li> | </li>
<li><a href="">Link2</a></li>
*/

?>
up
21
Anonymous
11 years ago
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.
up
13
masterandujar
11 years ago
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.
up
7
Anonymous
8 years ago
null values are imploded too. You can use array_filter() to sort out null values.

<?php
$ar
= array("hello", null, "world");
print(
implode(',', $ar)); // hello,,world
print(implode(',', array_filter($ar, function($v){ return $v !== null; }))); // hello,world
?>
up
-13
Rafael Pereira
4 years ago
If you want to use a key inside array:

Example:
$arr=array(
array("id" => 1,"name" => "Test1"),
array("id" => 2,"name" => "Test2"),
);

echo implode_key(",",$arr, "name");
OUTPUT: Test1, Test2

function implode_key($glue, $arr, $key){
$arr2=array();
foreach($arr as $f){
if(!isset($f[$key])) continue;
$arr2[]=$f[$key];
}
return implode($glue, $arr2);
}
up
-38
admin at lanlink dot net dot au
6 years ago
It is possible for an array to have numeric values, as well as string values. Implode will convert all numeric array elements to strings.

<?php
$test
=implode(["one",2,3,"four",5.67]);
echo
$test;
//outputs: "one23four5.67"
?>
up
-9
info AT sinistercircuits DOT com
2 years ago
There is no mention of behavior on a empty array, so I tried it and here's the result:

<?php
$ar
= array();
$result = implode(',', $ar); // Comma arbitrarily applied as the separator
$is_result_empty = empty($result);
?>

$result:
$is_result_empty: 1

In other words, an empty string is the result.
up
-19
info at ensostudio dot ru
3 years ago
<?php
* Join pieces with a string recursively.
*
* @
param mixed $glue String between pairs(glue) or an array pair's glue and key/value glue or $pieces.
* @param iterable $pieces Pieces to implode (optional).
* @return string Joined string
*/
function double_implode($glue, iterable $pieces = null): string
{
$glue2 = null;
if ($pieces === null) {
$pieces = $glue;
$glue = '';
} elseif (is_array($glue)) {
list($glue, $glue2) = $glue;
}

$result = [];
foreach ($pieces as $key => $value) {
$result[] = $glue2 === null ? $value : $key . $glue2 . $value;
}
return implode($glue, $result);
}
?>
Examples:
<?php
$array = ['
a' => 1, 'b' => 2];
$str = implode($array);
$str = implode('
, ', $array);
$str = implode(['" ', '="'], $array);

$iterator = new ArrayIterator($array);
$str = implode($iterator);
$str = implode('
, ', $iterator);
$str = implode(['" ', '="'], $iterator);
?>
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