Arrays: replace values with values from another array

Question

I have

$Array1 = [3=>'dog', 7=>'cat', 9=>'duck', 10=>'dog', 11=>'dog'];
$Array2 = ['cat'=>'sofa', 'dog'=>'kennel', 'duck'=>'pond'];

I want the output $ArrayOut where

$ArrayOut = [3=>'kennel', 7=>'sofa', 9=>'pond', 10=>'kennel', 11=>'kennel'];

I can do this easily through a foreach loop

foreach ($Array1 as $key => $value) {
    $ArrayOut[$key] = $Array2[$value];
}

but I was thinking if I could avoid a loop and use a combination of inbuilt PHP array functions to create the same output.

Any clue would be helpful thanks.

What is your logic toward trying achieving this array result? Show us the code you have tried. — MinistryOfChaps
– MinistryOfChaps, Commented Apr 5, 2018 at 14:22
The pattern is that the values of the first array is to be used as keys in the second array to find the replacement values. — Donnie Ashok
– Donnie Ashok, Commented Apr 5, 2018 at 14:24
I dont think there is a single build-in function to do this. But you can easily loop through the first array and fill a third array. — marcel.js
– marcel.js, Commented Apr 5, 2018 at 14:24

JrmC · Accepted Answer · 2018-04-05 14:44:14Z

4

I think this does the trick.

$Array1 = [3=>'dog', 7=>'cat', 9=>'duck', 10=>'dog', 11=>'dog'];
$Array2 = ['cat'=>'sofa', 'dog'=>'kennel', 'duck'=>'pond'];

$ArrayOut = array_map(function($v) use($Array2){
    return $Array2[$v];
}, $Array1);
print_r($ArrayOut);
//Array ( [3] => kennel [7] => sofa [9] => pond [10] => kennel [11] => kennel )

answered Apr 5, 2018 at 14:44

JrmC

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Comments

mickmackusa · Accepted Answer · 2021-09-09 09:21:30Z

There isn't (currently) a native function for this exact task. Using array_map() will require a user-function to be used. One benefit of functional-style iteration is that it reduces the number of global variables. Otherwise use a classic loop and modify the input array's values by reference. If any given value is not represented as key in the lookup array, then the null coalescing operator will just use the original value in the assignment. This avoids Notices without making any iterated function calls.

Code: (Demo)

$array = [3 => 'dog', 7 => 'cat', 9 => 'duck', 10 => 'dog', 11 => 'dog'];

$lookup = ['cat' => 'sofa', 'dog' => 'kennel', 'duck' => 'pond'];

foreach ($array as &$value) {
    $value = $lookup[$value] ?? $value;
}

var_export($array);

Code >=PHP7.4: (Demo)

var_export(
    array_map(fn($v) => $lookup[$v] ?? $v, $array)
);

Both Output:

array (
  3 => 'kennel',
  7 => 'sofa',
  9 => 'pond',
  10 => 'kennel',
  11 => 'kennel',
)

Community · Accepted Answer · 2020-06-20 09:12:55Z

-1

Edit: I have missread the purpose. Your best bet would be to work a foreach array in my opinion.

I'll still leave my answer here for future reference, if someone requires matching values from one array to keys of another array

There is something you can use, as long as your arrays are in the order you want.

http://php.net/manual/en/function.array-combine.php

http://php.net/manual/en/function.array-values.php

http://php.net/manual/en/function.array-keys.php

array_keys will extract into an array, the keys of a specified array

array_values will extract into an array, the values of specified array

array_combine will, as the function says, combine into an array the match arguments - being the first array argument the keys and the second the values.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Apr 5, 2018 at 14:24

abr

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4 Comments

Donnie Ashok Over a year ago

The second array is like a dictionary. The first array's length is variable and may not be equal to the length of the second array.

Lawrence Cherone Over a year ago

Obviously, but your not answering the OP question.

Syscall Over a year ago

Your code doesn't works with given input data outputs. Even if input arrays have same length, it will outputs : [3=>'sofa',...] instead of [3=>'kennel',...].

abr Over a year ago

You're right, I missread the question. Thought the output would be the merging of one's keys with one's values. edited, thanks and sorry

Giri Annamalai M · Accepted Answer · 2021-09-13 05:54:16Z

-1

Try this:

$Array1 = [3=>'dog', 7=>'cat', 9=>'duck'];
$Array2 = ['cat'=>'sofa', 'dog'=>'kennel', 'duck'=>'pond'];
# Flip the array
$new = array_flip($Array1);
# Replace the values
$new2 = array_replace($Array2, $new);
# This step you would lose the duplicates
$n = array_combine(array_merge($new2, $new), $Array2);
print_r($n);

Ouptut:

Array
(
    [7] => sofa
    [3] => kennel
    [9] => pond
)

edited Sep 13, 2021 at 5:54

answered Apr 5, 2018 at 14:42

Giri Annamalai M

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1 Comment

mickmackusa Over a year ago

This unexplained answer damages array data that may have duplicate values.

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