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!).

Answer 1

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)
));

Answer 2

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

Answer 3

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

Answer 4

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.

Answer 5

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

Answer 6

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, ",");

Answer 7

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";
}

Answer 8

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'))

Answer 9

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");

Answer 10

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;
    }

}

Answer 11

There is also var_export and print_r more commonly known for printing debug output but both functions can take an optional argument to return a string instead.

Using the example from the question as data.

$array = ["item1"=>"object1", "item2"=>"object2","item-n"=>"object-n"];

Using print_r to turn the array into a string

This will output a human readable representation of the variable.

$string = print_r($array, true);
echo $string;

Will output:

Array
(
    [item1] => object1
    [item2] => object2
    [item-n] => object-n
)

Using var_export to turn the array into a string

Which will output a php string representation of the variable.

$string = var_export($array, true);
echo $string;

Will output:

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

Because it is valid php we can evaluate it.

eval('$array2 = ' . var_export($array, true) . ';');
var_dump($array2 === $array);

Outputs:

bool(true)