On Mon, Dec 20, 2021 at 1:08 AM Yves Goergen via php-general <php-general@xxxxxxxxxxxxx> wrote:
Hello,
I'm looking for a PHP function that takes an array of objects
(associative arrays) and changes the keys to one of the subvalues. You
probably won't understand this, so I'll give an example.
Here's the source data:
[
[
'col1' => 'val1a',
'col2' => 'val2a',
'col3' => 'val3a'
],
[
'col1' => 'val1b',
'col2' => 'val2b',
'col3' => 'val3b'
],
[
'col1' => 'val1c',
'col2' => 'val2c',
'col3' => 'val3c'
]
]
The desired result for the index key 'col1' is:
[
'val1a' => [
'col1' => 'val1a',
'col2' => 'val2a',
'col3' => 'val3a'
],
'val1b' => [
'col1' => 'val1b',
'col2' => 'val2b',
'col3' => 'val3b'
],
'val1c' => [
'col1' => 'val1c',
'col2' => 'val2c',
'col3' => 'val3c'
]
]
All subarrays are still there (the order doesn't matter) but their keys
are changed from 0, 1, 2... to the value of their 'col1' entry so I can
access each subarray quickly and easily (and efficiently?) by its ID or
name or whatever.
That's similar to .NET LINQ's ToDictionary method that takes a key
selector delegate and builds exactly this structure. It can be used to
convert an ordinary database query result to a lookup dictionary.
I know I can write this in a handful of lines of code, but I need this
on a regular basis so before I roll my own version, I want to make sure
I haven't missed something that's already there. Preferably for PHP 7.4
and newer.
-Yves
Hi Yves,
This is ambiguous, there is no ready function and you will have to write one.
E.g.
function customFunction($array){
$output = [];
foreach($array as $i => $blob){
foreach($blob as $key => $value){
$output[$value] = $blob;
continue 2;
}
}
return $output;
}
$input = [
[
'col1' => 'val1a',
'col2' => 'val2a',
'col3' => 'val3a'
],
[
'col1' => 'val1b',
'col2' => 'val2b',
'col3' => 'val3b'
],
[
'col1' => 'val1c',
'col2' => 'val2c',
'col3' => 'val3c'
]
];
$output = customFunction($input);
echo json_encode($output);
$output = [];
foreach($array as $i => $blob){
foreach($blob as $key => $value){
$output[$value] = $blob;
continue 2;
}
}
return $output;
}
$input = [
[
'col1' => 'val1a',
'col2' => 'val2a',
'col3' => 'val3a'
],
[
'col1' => 'val1b',
'col2' => 'val2b',
'col3' => 'val3b'
],
[
'col1' => 'val1c',
'col2' => 'val2c',
'col3' => 'val3c'
]
];
$output = customFunction($input);
echo json_encode($output);
=========
{
"val1a":{
"col1":"val1a",
"col2":"val2a",
"col3":"val3a"
},
"val1b":{
"col1":"val1b",
"col2":"val2b",
"col3":"val3b"
},
"val1c":{
"col1":"val1c",
"col2":"val2c",
"col3":"val3c"
}
}
"val1a":{
"col1":"val1a",
"col2":"val2a",
"col3":"val3a"
},
"val1b":{
"col1":"val1b",
"col2":"val2b",
"col3":"val3b"
},
"val1c":{
"col1":"val1c",
"col2":"val2c",
"col3":"val3c"
}
}
- Jigar
