How to add new index and value from another array in PHP? - php

Question

I need your help with my problem. My problem is I have 2 arrays the first one is the main array. The second is the array for my new data.
Let's say I have these arrays.
This is the main array:
Array
(
0 => Array
(
'id' => 1,
'name' => 'Apple',
'age' => 12
)
1 => Array
(
'id' => 2,
'name' => May,
'age' => 13
)
)
This is the second array:
Array
(
1 => Array
(
'gender' => 'Male'
)
2 => Array
(
'gender' => 'Female'
)
)
And I have this loop in PHP
foreach($main_array as &$main){
//this is the loop inside the first array
// how can I add the second array with it?
}
This is the sample output:
[0] => Array
(
[id] => 1
[name] => Apple
[age] => 12
[gender] => Female
)
[1] => Array
(
[id] => 2
[name] => May
[age] => 13
[gender] => Female
)
How can I do that? Any suggestions? That's all thanks.

Answer 1

for($i=0; $i<count($main_array); $i++){
for($j=0; $j<count($second_array); $j++){
if($main_array[$i]['id'] == $j){
$main_array[$i]['gender'] = $second_array[$j]['gender']
}
}
}

Answer 2

I fixed your example code, it wont run otherwise.
<?php
// Test data:
$main_array = Array(
0 => Array(
'id' => 1,
'name' => 'Apple',
'age' => 12
),
1 => Array (
'id' => 2,
'name' => 'May',
'age' => 13
)
);
$lookup = Array(
1 => Array(
'gender' => 'Male'
),
2 => Array(
'gender' => 'Female'
)
);
// Your answer:
foreach ($main_array as &$main) {
if (array_key_exists($main['id'],$lookup)) {
$main['gender'] = $lookup[$main['id']]['gender']; // <-- sets gender value
}
}
// Output it to browser:
echo '<pre>$main_array = '.print_r($main_array,true).'</pre>';
The array_key_exists() check is there to avoid errors such as PHP Notice: Undefined offset: 123 when the $lookup data is incomplete.

Answer 3

If you want to merge all of the data from both arrays:
PHP tools:
The exact behaviors of these functions needs to be studied and tested before usage, to make sure it fits your intent.
// array merge recursive doesn't merge numeric keys
$main_array = array_merge_recursive($main_array, $secondary_array);
// array replace recursive has a downside of replacing stuff
$main_array = array_replace_recursive($main_array, $secondary_array);
Rolling your own:
foreach($main_array as $i => &$main){
if(isset($secondary_array[$i])) {
foreach($secondary_array[$i] AS $key => $value) {
$main[$key] = $value;
}
}
}
Both of the above solutions only apply if the array-indexes of $main_array and $secondary_array match.
In your example your arrays don't match:
- $secondary_array[0] doesn't exist so $main_array[0] will not be populated with a 'gender' value;
- $main_array[2] doesn't exist so $main_array[2] will be created and it will only have a 'gender' value same as $secondary_array[2]['gender']
If you want to only merge some bits and pieces of the arrays:
Rolling your own:
foreach($main_array as $i => &$main) {
if(isset($secondary_array[$i])) and isset($secondary_array[$i]['gender'])) {
$main['gender'] = $secondary_array[$i]['gender'];
}
}

Answer 4

foreach($main_array as &$main){//this is the loop inside the first array
foreach($second_array as &$second){ //this is the loop inside the second array
}
}

Answer 5

foreach($arr1 as $k => $arr1Item) {
$arr1[$k]['gender'] = $arr2[$k]['gender'];
}