Hierarchical Array Conversion to Flat Array [duplicate] - php

Question

This question already has answers here:
Merge two flat indexed arrays of equal size so that values are pushed into the result in an alternating fashion
(2 answers)
Closed 10 months ago.
I've got an array
$array = array(
array(1,2,3),
array('bob','bill'),
array(4,5,6,7)
//can have between 0 and 5 "rows"
);
I want to convert to an array that looks like this...
[1,bob,4, 1, bob, 5, 1, bob, 6, 1, bob, 7, 1, bill, 4 .... 3, bill, 7]
I was trying to write a recursive function for this which looks like...
function GetValues($array, $rowIndex, $valIndex, $values)
{
if(!isset($array[$rowIndex]))
{
return $values;
}
if(!isset($array[$rowIndex][$valIndex]))
{
return GetValues($array,$rowIndex+1, 0, $values);
}
$values[] = $array[$rowIndex][$valIndex];
return GetValues($array,$rowIndex, $valIndex+1, $values);
}
which just ends up iterating the array normally (prints 1,2,3,bob,bill,4,5,6,7)

Answer 1

$array = array(
array(1,2,3),
array('bob','bill'),
array(4,5,6,7)
);
function combinations($arrays) {
$result[] = array();
foreach ($arrays as $key => $values) {
$tmp = array();
foreach ($result as $result_item) {
foreach ($values as $value) {
$tmp[] = array_merge($result_item, array($key => $value));
}
}
$result = $tmp;
}
return $result;
}
$combinations_array = combinations($array);
$flat_string = '';
$flat_array = array();
foreach($combinations_array as $value){
foreach($value as $v){
$flat_string.=$v.',';
$flat_array[]=$v;
}
}
echo rtrim($flat_string,',');
print_r($flat_array);
Out Put string:
1,bob,4,1,bob,5,1,bob,6,1,bob,7,1,bill,4,1,bill,5,1,bill,6,1,bill,7,2,bob,4,2,bob,5,2,bob,6,2,bob,7,2,bill,4,2,bill,5,2,bill,6,2,bill,7,3,bob,4,3,bob,5,3,bob,6,3,bob,7,3,bill,4,3,bill,5,3,bill,6,3,bill,7
Output array:
Array
(
[0] => 1
[1] => bob
[2] => 4
[3] => 1
[4] => bob
[5] => 5
[6] => 1
[7] => bob
[8] => 6
[9] => 1
[10] => bob
[11] => 7
[12] => 1
[13] => bill
[14] => 4
[15] => 1
[16] => bill
[17] => 5
[18] => 1
[19] => bill
[20] => 6
[21] => 1
[22] => bill
[23] => 7
[24] => 2
[25] => bob
[26] => 4
[27] => 2
[28] => bob
[29] => 5
[30] => 2
[31] => bob
[32] => 6
[33] => 2
[34] => bob
[35] => 7
[36] => 2
[37] => bill
[38] => 4
[39] => 2
[40] => bill
[41] => 5
[42] => 2
[43] => bill
[44] => 6
[45] => 2
[46] => bill
[47] => 7
[48] => 3
[49] => bob
[50] => 4
[51] => 3
[52] => bob
[53] => 5
[54] => 3
[55] => bob
[56] => 6
[57] => 3
[58] => bob
[59] => 7
[60] => 3
[61] => bill
[62] => 4
[63] => 3
[64] => bill
[65] => 5
[66] => 3
[67] => bill
[68] => 6
[69] => 3
[70] => bill
[71] => 7
)

Answer 2

A problem you will likely have is not knowing how big the original array is. You can write it recursively by destroying the array. In this example, I shift the first element off the original array. Then, with each recursive call, I shift off another element. I use a for loop to go through the values and return what I've built.
function flatten($array)
{
if(sizeof($array)==0) return null;
$first = array_shift($array);
$ret = array();
foreach($first as $value)
{
$ret[] = $value;
$sub = flatten($array);
if($sub != null)
$ret = array_merge($ret, $sub);
}
return $ret;
}