Read external variable with create_function php

Question

I need to append a prefix to each key in my array. The prefix it is defined outside the create_function I am using. How can I make it accessible from inside?

Here my code ($result is my array of key => value):

$groupName = $reader->getAttribute('name');

$resultKeyPrefixGroup = array_combine(
                    array_map(create_function('$k', 'return $groupName."/".$k;'), array_keys($result)),
                    $result
                );

Thank you!

Possible duplicate of [Fastest way to add prefix to array keys?](https://stackoverflow.com/questions/2607595/fastest-way-to-add-prefix-to-array-keys) — mickmackusa, Jul 18 '18 at 08:46

Progrock · Answer 1 · 2018-07-12T12:44:18.887

1

This hurt my brain wrapping my head around escaping the string:

<?php
$result = 
[
    '1' => 'One',
    '2' => 'Two'
];

$groupName = 'braves';

$resultKeyPrefixGroup = array_combine(
    array_map(
        create_function('$k', "return '$groupName/'.\$k;"),
        array_keys($result)
    ),
    $result
);
var_export($resultKeyPrefixGroup);

Output:

array (
    'braves/1' => 'One',
    'braves/2' => 'Two',
)

As create_function is deprecated as of 7.2.0 I'd recommend one of my alternative approaches.

edited Jul 12 '18 at 12:44

answered Jul 12 '18 at 11:31

Progrock

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1

This `"return '$groupName/'".'.$k;'` or `"return '$groupName/'.\$k;"` any better? Nice logic puzzle. – Xorifelse Jul 12 '18 at 12:05
@Xorifelse, that's much better. I obviously didn't break my brain enough. – Progrock Jul 12 '18 at 12:44

score 0 · Answer 2 · answered Jul 12 '18 at 11:14

You could use an anonymous function:

<?php
$result = 
[
    '1' => 'One',
    '2' => 'Two'
];

$prefix = 'pink/';
$prefix_key = function($str) use ($prefix) {
    return $prefix . $str;
};

$prefixed = array_combine(
    array_map($prefix_key, array_keys($result)),
    $result
);

var_export($prefixed);

Output:

array (
  'pink/1' => 'One',
  'pink/2' => 'Two',
)

Though it might be just as well to loop and build your new array:

foreach($result as $k => $v)
    $prefixed["pink/$k"] = $v;

Read external variable with create_function php

2 Answers2