How to implode subarrays in a 2-dimensional array? - php

Question

I want to implode values in to a comma-separated string if they are an array:
I have the following array:
$my_array = [
"keywords" => "test",
"locationId" => [ 0 => "1", 1 => "2"],
"industries" => "1"
];
To achieve this I have the following code:
foreach ($my_array as &$value)
is_array($value) ? $value = implode(",", $value) : $value;
unset($value);
The above will also change the original array. Is there a more elegant way to create a new array that does the same as the above?
I mean, implode values if they are an array in a single line of code? perhaps array_map()? ...but then I would have to create another function.

Answer 1

Just create a new array and set the elements (-;
<?php
...
$new_array = [];
foreach ($my_array as $key => $value)
$new_array[$key] = is_array($value) ? implode(",", $value) : $value;

Answer 2

Just append values to new array:
$my_array = [
"keywords" => "test",
"locationId" => [ 0 => "1", 1 => "2"],
"industries" => "1",
];
$new_Array = [];
foreach ($my_array as $value) {
$new_Array[] = is_array($value) ? implode(",", $value) : $value;
}
print_r($new_Array);
And something that can be called a "one-liner"
$new_Array = array_reduce($my_array, function($t, $v) { $t[] = is_array($v) ? implode(",", $v) : $v; return $t; }, []);
Now compare both solutions and tell which is more readable.

Answer 3

You don't need to write/iterate a conditional statement if you type the strings (non-arrays) as single-element arrays before imploding them.
With array_map(): (Demo)
$my_array = [
"keywords" => "test",
"locationId" => [ 0 => "1", 1 => "2"],
"industries" => "1"
];
var_export(
array_map(
function($v) {
return implode(',', (array)$v);
},
$my_array
)
);
Or from PHP7.4, array_map() with arrow function syntax: (Demo)
var_export(
array_map(fn($v) => implode(',', (array)$v), $my_array)
);
Or array_walk() and modification by reference (Demo)
array_walk(
$my_array,
function(&$v) {
$v = implode(',', (array)$v);
}
);
var_export($my_array);
Or a foreach loop: (Demo)
foreach ($my_array as &$v) {
$v = implode(',', (array)$v);
}
var_export($my_array);
All snippets will output:
array (
'keywords' => 'test',
'locationId' => '1,2',
'industries' => '1',
)

Answer 4

$arr = array( 'key1' => array( 'one', 'key2' => array( 'two',
'three' ) ), 'four', 'five' );
$finalData = [];
array_walk_recursive(
$arr,
function( $subArr ) use ( &$finalData ) {
$finalData[] = $subArr;
}
);
$str = is_array( $finalData ) ? implode( ",", $finalData ) : $finalData;
print_r( $str ); // one,two,three,four,five