How to implode array with key and value without foreach in PHP

Question

Without foreach, how can I turn an array like this

array("item1"=>"object1", "item2"=>"object2",......."item-n"=>"object-n");

to a string like this

item1='object1', item2='object2',.... item-n='object-n'

I thought about implode() already, but it doesn't implode the key with it.

If foreach it necessary, is it possible to not nest the foreach?

EDIT: I've changed the string

EDIT2/UPDATE: This question was asked quite a while ago. At that time, I wanted to write everything in one line so I would use ternary operators and nest built in function calls in favor of foreach. That was not a good practice! Write code that is readable, whether it is concise or not doesn't matter that much.

In this case: putting the foreach in a function will be much more readable and modular than writing a one-liner(Even though all the answers are great!).

this was my database class for web app i'm building, i don't want it to look messy since it's already populated with a bunch of foreach and for-loop all together — tom91136, Jul 11 '12 at 07:30
This selected answer is method that you asked for, however it should be noted that it is critically slower and that if you are storing this information via a database it would be vastly superior to both a loop and this to just use json_encode. Exhibit A: http://willem.stuursma.name/2010/11/22/a-detailed-look-into-array_map-and-foreach/ — Case, Sep 07 '13 at 05:16
possible duplicate of [Fastest way to implode an associative array with keys](http://stackoverflow.com/questions/408032/fastest-way-to-implode-an-associative-array-with-keys) — Félix Adriyel Gagnon-Grenier, Jul 07 '15 at 18:42

score 245 · Answer 1 · answered Jul 11 '12 at 07:20

245

You could use http_build_query, like this:

<?php
  $a=array("item1"=>"object1", "item2"=>"object2");
  echo http_build_query($a,'',', ');
?>

Output:

item1=object1, item2=object2

Demo

answered Jul 11 '12 at 07:20

stewe

41,820
13
79
75

1

is it possible to make the object1 into 'object1' – tom91136 Jul 11 '12 at 07:23
11

Beware of the string encoding!If you are not building an URL maybe you do not want it on your array key&value – Matteo Sep 10 '14 at 12:51
13

@Matteo You can wrap `http_build_query` in `urldecode` to avoid it. – Afterlame Nov 19 '14 at 11:24
3

Genius solution. That was all I needed for a debug output of am assoc array. – dixus Apr 01 '15 at 13:43
Anyway to omit `key` itself? – Volatil3 Sep 15 '15 at 11:23
1

One should be aware of how the 4th parameter handles white space. – kaiser Sep 08 '16 at 08:08
It changes your values if have space in it. The `http_build_query` replaces spaces with plus (`+` ) character. – Erfun Apr 22 '20 at 21:34
3

Just because you can use a brick to hammer in a nail, does not mean you should. Someone may change the shape of the brick not thinking someone is using it in place of a hammer. Use the correct tools for the job, for future-proofing a solution. – Paul Allsopp Apr 05 '21 at 21:08

score 213 · Accepted Answer · edited Apr 27 '16 at 08:28

213

and another way:

$input = array(
    'item1'  => 'object1',
    'item2'  => 'object2',
    'item-n' => 'object-n'
);

$output = implode(', ', array_map(
    function ($v, $k) {
        if(is_array($v)){
            return $k.'[]='.implode('&'.$k.'[]=', $v);
        }else{
            return $k.'='.$v;
        }
    }, 
    $input, 
    array_keys($input)
));

or:

$output = implode(', ', array_map(
    function ($v, $k) { return sprintf("%s='%s'", $k, $v); },
    $input,
    array_keys($input)
));

edited Apr 27 '16 at 08:28

SebHallin

881
6
11

answered Jul 11 '12 at 07:23

Yoshi

54,081
14
89
103

7

This method is what the Author was asking for, but it should be noted that it is critically slower and that if you are storing this information via a database it would be vastly superior to both a loop and this to just use json_encode. Exhibit A: http://willem.stuursma.name/2010/11/22/a-detailed-look-into-array_map-and-foreach/ – Case Sep 07 '13 at 05:14
None of the links here seem to work anymore, they all `echo "Hello, World!";` Should I be seeing code examples of those functions? – Félix Adriyel Gagnon-Grenier Jul 07 '15 at 18:36
This method is very easy to customize according to own demand. – Kabir Hossain Nov 24 '16 at 04:01
I was using this method to build select options and populate the selected option, and since both arrays must be the same size you can do something like this for the second array. `array_fill(0, $input, 'selected-value-you want-to-check-against');` This will generate same size array with single value for all the rows. – krasenslavov Dec 18 '19 at 00:08

Maxim Tkach · Answer 3 · 2016-06-17T15:40:47.673

52

I spent measurements (100000 iterations), what fastest way to glue an associative array?

Objective: To obtain a line of 1,000 items, in this format: "key:value,key2:value2"

We have array (for example):

$array = [
    'test0' => 344,
    'test1' => 235,
    'test2' => 876,
    ...
];

Test number one:

Use http_build_query and str_replace:

str_replace('=', ':', http_build_query($array, null, ','));

Average time to implode 1000 elements: 0.00012930955084904

Test number two:

Use array_map and implode:

implode(',', array_map(
        function ($v, $k) {
            return $k.':'.$v;
        },
        $array,
        array_keys($array)
    ));

Average time to implode 1000 elements: 0.0004890081976675

Test number three:

Use array_walk and implode:

array_walk($array,
        function (&$v, $k) {
            $v = $k.':'.$v;
        }
    );
implode(',', $array);

Average time to implode 1000 elements: 0.0003874126245348

Test number four:

Use foreach:

    $str = '';
    foreach($array as $key=>$item) {
        $str .= $key.':'.$item.',';
    }
    rtrim($str, ',');

Average time to implode 1000 elements: 0.00026632803902445

I can conclude that the best way to glue the array - use http_build_query and str_replace

edited Jun 17 '16 at 15:40

answered Jun 17 '16 at 15:12

Maxim Tkach

1,607
12
23

5

`$s = ''; foreach ($array as $k=>$v) { if ($s !== null) { $s .= ','; } $s .= "{$k}:{$v}"; }` outperforms all others. – Fleshgrinder Jan 11 '17 at 11:36
4

The http_build_query bench is missing urldecode to be comparative to the others. – nickl- Mar 28 '19 at 22:11
Another option: `substr(str_replace('"', '', json_encode($headers)), 1, -1);` – nickl- Mar 28 '19 at 22:27
2

CAUTION: It changes your values if have space in it. The `http_build_query` replaces spaces with plus (`+` ) character. – Erfun Apr 22 '20 at 21:33
1

I just tested `http_build_query`+`urldecode` vs implode. Implode was 10 times faster. – CodeBrauer Oct 19 '20 at 13:29

score 12 · Answer 4 · edited Sep 02 '16 at 12:11

12

I would use serialize() or json_encode().

While it won't give your the exact result string you want, it would be much easier to encode/store/retrieve/decode later on.

edited Sep 02 '16 at 12:11

NHG

5,807
6
34
45

answered Jul 11 '12 at 07:13

Madara's Ghost

172,118
50
264
308

score 4 · Answer 5 · answered Jul 11 '12 at 07:28

4

Using array_walk

$a = array("item1"=>"object1", "item2"=>"object2","item-n"=>"object-n");
$r=array();
array_walk($a, create_function('$b, $c', 'global $r; $r[]="$c=$b";'));
echo implode(', ', $r);

IDEONE

answered Jul 11 '12 at 07:28

Shiplu Mokaddim

56,364
17
141
187

1

I like the array_walk approach, but I don't understand why people suggest using `create_function` instead of just using an anonymous function? – Rikki May 04 '14 at 18:27
@Rikki Compatibility! – Shiplu Mokaddim May 05 '14 at 04:36
Ah! I didn't realise it was a PHP4 thing! – Rikki May 13 '14 at 00:08
@Rikki **No**. Its pre PHP 5.3 thing. [Anonymous function](http://php.net/manual/en/functions.anonymous.php) first appeared on PHP 5.3 – Shiplu Mokaddim May 13 '14 at 11:10
**But** it was introduced in PHP 4.0.1, so is a PHP4 thing. Semantics... Adding a feature as significant as anonymous functions in a minor version update is bizarre. – Rikki May 14 '14 at 14:58

sapenov · Answer 6 · 2017-02-27T22:22:09.243

4

You could use PHP's array_reduce as well,

$a = ['Name' => 'Last Name'];

function acc($acc,$k)use($a){ return $acc .= $k.":".$a[$k].",";}

$imploded = array_reduce(array_keys($a), "acc");

edited Feb 27 '17 at 22:22

answered Feb 27 '17 at 22:05

sapenov

1,501
1
10
7

score 3 · Answer 7 · edited Sep 11 '15 at 11:05

3

Change

-    return substr($result, (-1 * strlen($glue)));
+    return substr($result, 0, -1 * strlen($glue));

if you want to resive the entire String without the last $glue

function key_implode(&$array, $glue) {
    $result = "";
    foreach ($array as $key => $value) {
        $result .= $key . "=" . $value . $glue;
    }
    return substr($result, (-1 * strlen($glue)));
}

And the usage:

$str = key_implode($yourArray, ",");

edited Sep 11 '15 at 11:05

Community

1
1

answered Jul 11 '12 at 07:16

Björn

29,019
9
65
81

why are you using a reference array in key_implode? – Eboubaker Sep 11 '22 at 11:20
you should return `substr($result, 0, strlen($result) - strlen($glue))`, because your substr will only return the glue value – Eboubaker Sep 11 '22 at 11:35

Sergey Yurich · Answer 8 · 2015-11-24T10:52:13.663

For debugging purposes. Recursive write an array of nested arrays to a string. Used foreach. Function stores National Language characters.

function q($input)
{
    $glue = ', ';
    $function = function ($v, $k) use (&$function, $glue) {
        if (is_array($v)) {
            $arr = [];
            foreach ($v as $key => $value) {
                $arr[] = $function($value, $key);
            }
            $result = "{" . implode($glue, $arr) . "}";
        } else {
            $result = sprintf("%s=\"%s\"", $k, var_export($v, true));
        }
        return $result;
    };
    return implode($glue, array_map($function, $input, array_keys($input))) . "\n";
}

score 3 · Answer 9 · answered May 04 '18 at 15:30

Here is a simple example, using class:

$input = array(
    'element1'  => 'value1',
    'element2'  => 'value2',
    'element3' =>  'value3'
);

echo FlatData::flatArray($input,', ', '=');

class FlatData
{

    public static function flatArray(array $input = array(), $separator_elements = ', ', $separator = ': ')
    {
        $output = implode($separator_elements, array_map(
            function ($v, $k, $s) {
                return sprintf("%s{$s}%s", $k, $v);
            },
            $input,
            array_keys($input),
            array_fill(0, count($input), $separator)
        ));
      return $output;
    }

}

Ajay Patidar · Answer 10 · 2017-05-24T10:23:42.417

For create mysql where conditions from array

$sWheres = array('item1'  => 'object1',
                 'item2'  => 'object2',
                 'item3'  => 1,
                 'item4'  => array(4,5),
                 'item5'  => array('object3','object4'));
$sWhere = '';
if(!empty($sWheres)){
    $sWhereConditions = array();
    foreach ($sWheres as $key => $value){
        if(!empty($value)){
            if(is_array($value)){
                $value = array_filter($value); // For remove blank values from array
                if(!empty($value)){
                    array_walk($value, function(&$item){ $item = sprintf("'%s'", $item); }); // For make value string type 'string'
                    $sWhereConditions[] = sprintf("%s in (%s)", $key, implode(', ', $value));
                }
            }else{
                $sWhereConditions[] = sprintf("%s='%s'", $key, $value);
            }
        }
    }
    if(!empty($sWhereConditions)){
        $sWhere .= "(".implode(' AND ', $sWhereConditions).")";
    }
}
echo $sWhere;  // (item1='object1' AND item2='object2' AND item3='1' AND item4 in ('4', '5') AND item5 in ('object3', 'object4'))

score 1 · Answer 11 · answered May 22 '22 at 14:26

1

Short one:

$string = implode('; ', array_map(fn($k, $v) => "$k=$v", array_keys($array), $array));

answered May 22 '22 at 14:26

Andy Webov

508
1
5
8

score 0 · Answer 12 · answered Dec 19 '21 at 07:32

Using explode to get an array from any string is always OK, because array is an always in standard structure.

But about array to string, is there any reason to use predefined string in codes? while the string SHOULD be in any format to use!

The good point of foreach is that you can create the string AS YOU NEED IT! I'd suggest still using foreach quiet readable and clean.

$list = array('a'=>'1', 'b'=>'2', 'c'=>'3');

$sql_val = array();
foreach ($list as $key => $value) {
    $sql_val[] = "(" . $key . ", '" . $value . "') ";
}
$sql_val = implode(', ', $sql_val);

with results:

(a, '1') , (b, '2') , (c, '3')

|

(a: '1') , (b: '2') , (c: '3')

|

a:'1' , b:'2' , c:'3'

etc.

score 0 · Answer 13 · answered Apr 18 '23 at 10:01

I was looking for a solution to this question and I know it's been 10 years old but halfway the page, I thought: why not string replace on a json encode. It will give you easy access on how to configure the string. Also, it's a oneliner that avoids a (foreach) loop.

It would look something like this:

$wrapperAttributesString = str_replace(['{"' , '"}', '":', '","'],['' , '', '=', ' '], json_encode($wrapperAttributes));

So, bassically what happens here is:

$wrapperAttributes['class'] = 'hi__stack--overflow';
$wrapperAttributes['style'] = 'overflow: stack; ';
$wrapperAttributes['id']    = 'oneliner_array_with_keys_tostring_attributes';

//if we were to json encode this array: it would result in this:
// {"class":"hi__stack--overflow","style":"overflow: stack; ","id":"oneliner_array_with_keys_tostring_attributes"}

now the str_replace first argument takes an array with find what, the second is an array to replace that with. so it does:

find {" and replace with nothing;

find }" and replace with nothing;

find ": and replace with =;

find "," and replace with " ; to close the attribute and space to chain next

the output would be

class="hi__stack--overflow" style="overflow: stack; " id="oneliner_array_with_keys_tostring_attributes"

Now if you woud like to have comma separated instead of space separated string, just change the last replace into find "," with ','

the output would become

class="hi__stack--overflow",style="overflow: stack; ",id="oneliner_array_with_keys_tostring_attributes

Be aware, that this might be safe for html attributes (considering the values should never have a doubleqoute), but I would definitly not use it where the values can have the same combinations as the replaces have.

This is my first post, so, if you have any feedback. Feel free to let me know, also, if I by accident, did not abide by any standards, then let me know and i wil change it asap :)

score -1 · Answer 14 · answered Sep 02 '22 at 16:05

Also if the question is outdated and the solution not requested anymore, I just found myself in the need of printing an array for debugging purposes (throwing an exception and showing the array that caused the problem).

For this reason, I anyway propose my simple solution (one line, like originally asked):

$array = ['a very' => ['complex' => 'array']];
$imploded = var_export($array, true);

This will return the exported var instead of directly printing it on the screen and the var $imploded will contain the full export.

How to implode array with key and value without foreach in PHP

14 Answers14

Linked

Related