Convert an associative array into a string of HTML element attribute assignments

Question

I want to convert array values into string. What should I use to join them as presented in goal?

Should I use serialize() or implode() or http_build_query() or array_walk() ?

$attributes = array(
    'autocomplete' => 'off',
    'class' => 'email',
    'id' => 'myform'
);

echo http_build_query($attributes, '', '" ');

// output
autocomplete=off" class=email" id=myform

Goal:

// output 
autocomplete="off" class="email" id="myform"

Edit:

I used array_walk() to gain goal

function myfunction($value, $key) {
    echo $key . '=" ' . $value . ' " ';
}

array_walk($atributes, "myfunction");

h2ooooooo · Accepted Answer · 2013-11-21 10:17:57Z

If you want to make sure that you'll get exactly the same array back, you have to use serialize (as it'll keep variable types) and unserialize to get your data back. Alternately, json_decode and json_encode work as well (but only maintains simple types as int/float/string/boolean/NULL). The data will be larger than implode and http_build_query, though.

Examples:

Consider the following array:

$array = array(
    'foo' => 'bar',
    'bar' => false,
    'rab' => null,
    'oof' => 123.45
);

serialize/unserialize:

<?php
    var_dump( unserialize( serialize($array) ) );
    /*
        array(4) {
            ["foo"] => string(3) "bar"
            ["bar"] => bool(false)
            ["rab"] => NULL
            ["oof"] => float(123.45)
        }
    */
?>

implode/explode:

<?php
    var_dump( explode('&', implode('&', $array) ) );
    /*
        array(4) {
            [0] => string(3) "bar"
            [1] => string(0) ""
            [2] => string(0) ""
            [3] => string(6) "123.45"
        }
    */
?>

json_encode/json_decode:

<?php
    var_dump( json_decode( json_encode($array) , true) );
    /*
        array(4) {
            ["foo"] => string(3) "bar"
            ["bar"] => bool(false)
            ["rab"] => NULL
            ["oof"] => float(123.45)
        }
    */
?>

http_build_query/parse_str:

<?php
    parse_str( http_build_query($array) , $params);
    var_dump( $params );
    /*
        array(3) {
            ["foo"] => string(3) "bar"
            ["bar"] => string(1) "0"
            ["oof"] => string(6) "123.45"
        }
    */
?>

DEMO

Shankar Narayana Damodaran · Accepted Answer · 2013-11-21 10:10:40Z

1

The http_build_query is the best option here since you have key=>value combinations

answered Nov 21, 2013 at 10:10

Shankar Narayana Damodaran

68.6k43 gold badges102 silver badges129 bronze badges

Comments

Josh Harrison · Accepted Answer · 2013-11-21 10:19:48Z

It looks like you want to combine these into a string for outputting on an HTML tag.

This reusable function should produce your desired result:

function get_attribute_string($attr_array) {
    $attributes_processed = array();
    foreach($attr_array as $key => $value) {
        $attributes_processed[] = $key . '="' . $value . '"';
    }

    return implode($attributes_processed, ' ');
}

$atributes = array(
    'autocomplete' => 'off',
    'class' => 'email',
    'id' => 'myform'
);

// this string will contain your goal output
$attributes_string = get_attribute_string($atributes);

P.S. atributes should have three Ts - attributes - mind this doesn't catch you out!

Ing. Michal Hudak · Accepted Answer · 2013-11-21 10:22:50Z

0

Used array_walk() to gain goal

function myfunction($value, $key) {
    echo $key . '="' . $value . '" ';
}

array_walk($atributes, "myfunction");

answered Nov 21, 2013 at 10:22

Ing. Michal Hudak

5,64212 gold badges63 silver badges95 bronze badges

Comments

mickmackusa · Accepted Answer · 2024-10-06 20:31:38Z

If you are building HTML element attribute declarations with quotes, you should probably encode entities which can interfere with document validity.

How you loop is less important, find a style that you are comfortable with and will be able to maintain in the future.

Code: (Demo)

echo implode(
         ' ',
         array_map(
             fn($k, $v) => sprintf(
                 '%s="%s"',
                 $k,
                 htmlspecialchars(
                     $v,
                     ENT_QUOTES,
                     'UTF-8'
                 )
             ),
             array_keys($attributes),
             $attributes
         )
      );

Input:

$attributes = array(
    'autocomplete' => 'off',
    'class' => 'email',
    'id' => 'myform',
    'value' => 'foo "fizz buzz" bar',
);

Output:

autocomplete="off" class="email" id="myform" value="foo &quot;fizz buzz&quot; bar"

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