Use array_column in combination with preg_match - php

Question

Lets suppose we have an array of arrays that needs to be converted to rows
From this:
Array
(
[subject] => Array
(
[0] => EDN:LOC:DERR
[1] => EDN:LOC:DOXX
[2] => EDN:LOC:NTTT
[3] => EDN:LOC:NAGA
)
[object] => Array
(
[0] => ABS:D01::ADFPAZ01
[1] => ABS:D01::DOXYWITX
[2] => ABS:D01::NAGBAAD2
[3] => ABS:D01::NAGGAAD2
)
[units] => Array
(
[0] => ABS:D06::UNAA
[1] => ABS:D06::UMMM
[2] => ABS:D06::UPOP
[3] => ABS:D06::UPOP
)
To this:
[0] => "'DERR' , 'ADFPAZ01' , 'UNAA'"
[1] => "'DOXX' , 'DOXYWITX' , 'UMMM'"
[2] => "'NTTT' , 'NAGBAAD2' , 'UPOP'"
[3] => "'NAGA' , 'NAGGAAD2' , 'UPOP'"
So I need the arrays to be cleaned by a pattern and compressed into lines.
I managed the compact view with the following function
$array_res = array();
for ($i=0; $i<=$totalEntries-1; $i++) {
array_push($array_res, implode("', '", array_column($array_of_arrays, $i)));
}
My regex pattern is $pattern = '([^.:]*$)'; And it collects a sequence of letters from the end of the string until it finds a colon. And I used preg_match($pattern, $string, $match) to receive the proper string into the $match variable.
However, I cannot combine the above two procedures either with array_filter or array_map inside the for loop.
EDIT: Note that there can be a subarray that contains values without a colon. In that case we have to get the value as is
[units] => Array
(
[0] => NULL
[1] => VALUE1
[2] => VALUE2
[3] => NULL
)

Answer 1

Rather than using a regex, this just uses array_walk() to process the extracted column and for each item it uses strrchr() with : as the last character to match (although it will include the :, so uses substr() to remove the first char)...
for ($i=0; $i<=$totalEntries-1; $i++) {
$newRow = array_column($array_of_arrays, $i);
array_walk($newRow, function (&$data) {
$data = substr(strrchr(":".$data, ":") , 1);
});
$array_res[] = "'".implode("', '", $newRow)."'";
}
The part ":".$data deals with the time when there is no : in the string, it will always ensure that it does find something to use.

Answer 2

Other way:
$arr = [
'subject' => [ 'EDN:LOC:DERR', 'EDN:LOC:DOXX', 'EDN:LOC:NTTT', 'EDN:LOC:NAGA' ],
'object' => [ 'ABS:D01::ADFPAZ01', 'ABS:D01::DOXYWITX', 'ABS:D01::NAGBAAD2', 'ABS:D01::NAGGAAD2' ],
'units' => [ 'ABS:D06::UNAA', 'ABS:D06::UMMM', 'ABS:D06::UPOP', 'ABS:D06::UPOP' ]
];
$res = [];
$fmt = "'%s', '%s', '%s'";
foreach ($arr['subject'] as $k => $v) {
$res[] = vsprintf($fmt, preg_replace('~^.*:~', '', array_column($arr, $k)));
}
print_r($res);
Notice: If you don't know in advance your array length, nothing forbids to build the format pattern dynamically (using str_repeat or implode).