implode

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

implode — 将一个一维数组的值转化为字符串

说明

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

用 glue 将一维数组的值连接为一个字符串。

Note:

因为历史原因，implode() 可以接收两种参数顺序，但是为了和 explode() 内的顺序保持一致，不按文档的方式已被废弃。

参数

glue

默认为空的字符串。

pieces

你想要转换的数组。

返回值

返回一个字符串，其内容为由 glue 分割开的数组的值。

更新日志

版本 说明
7.4.0 把参数 glue 放到 pieces 的后面已被废弃（就是不按文档中的顺序传递参数）。

范例

Example #1 implode() 例子

<?php

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

echo $comma_separated; // lastname,email,phone

// Empty string when using an empty array:
var_dump(implode('hello', array())); // string(0) ""

?>

注释

Note: 此函数可安全用于二进制对象。

参见

User Contributed Notes

biziclop 09-Apr-2021 10:30
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>
*/

?>
info at ensostudio dot ru 28-Aug-2020 05:32
<?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);
?>
Honk der Hase 24-Apr-2020 05:43
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

?>
Rafael Pereira 02-Apr-2020 04:28
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);
}
ASchmidt at Anamera dot net 23-Nov-2018 09:43
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
admin at lanlink dot net dot au 15-Sep-2017 04:24
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"
?>
Felix Rauch 30-Sep-2016 09:39
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
Anonymous 20-Jul-2015 11:55
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
?>
omar dot ajoue at kekanto dot com 18-Mar-2013 02:21
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! ;)
Anonymous 26-Feb-2013 03:56
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.
masterandujar 03-Sep-2012 06:15
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.
alexey dot klimko at gmail dot com 23-Jun-2011 05:04
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.
houston_roadrunner at yahoo dot com 07-Apr-2009 11:50
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: ''
php.net {at} nr78 {dot} net 30-Mar-2005 06:50
Also quite handy in INSERT statements:

<?php

   // array containing data
   $array = array(
      "name" => "John",
      "surname" => "Doe",
      "email" => "[email protected]"
   );

   // 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());

?>