implode

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

implode用字符串连接数组元素

说明

implode(string $separator, array $array): string

替代写法(不支持命名参数):

implode(array $array): string

遗留写法(从 PHP 7.4.0 起废弃,从 PHP 8.0.0 中移除):

implode(array $array, string $separator): string

用一个 separator 字符串连接数组元素。

参数

separator

可选。默认为空字符串。

array

要使用字符串连接的数组。

返回值

返回一个包含所有数组元素并且顺序相同的字符串, 每个元素之间有 separator 分隔。

更新日志

版本 说明
8.0.0 array 之后传递 separator 已不再支持。
7.4.0 array 之后传递 separator (即:使用遗留写法)已被废弃。

示例

示例 #1 implode() 例子

<?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"

?>

注释

注意: 此函数可安全用于二进制对象。

参见

add a note add a note

User Contributed Notes 14 notes

up
325
houston_roadrunner at yahoo dot com
14 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
61
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
107
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
18
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
37
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
53
php.net {at} nr78 {dot} net
18 years ago
Also quite handy in INSERT statements:

<?php

  
// array containing data
  
$array = array(
     
"name" => "John",
     
"surname" => "Doe",
     
"email" => "j.doe@intelligence.gov"
  
);

  
// build query...
  
$sql  = "INSERT INTO table";

  
// implode keys of $array...
  
$sql .= " (`".implode("`, `", array_keys($array))."`)";

  
// implode values of $array...
  
$sql .= " VALUES ('".implode("', '", $array)."') ";

  
// execute query...
  
$result = mysql_query($sql) or die(mysql_error());

?>
up
17
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
20
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
4
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
1
biziclop
2 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
0
Honk der Hase
3 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
-1
Rafael Pereira
3 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
-29
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 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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