I have 2 arrays :
$arr1 = array('1', '2', '3', '4', '5', '6', '7');
$arr2 = array('a', 'b', 'c', 'd', 'e');
I want to loop $arr2 into $arr1 but if the length of $arr1 is less than the algorithm requires, only use as many elements of $arr2 as necessary.
I want to achieve this result:
$arr2 = array('1', '2', '3', 'a', '4', '5', '6', 'b', '7');
I have already tried :
$count = ceil(count($arr1) / 3) - 1;
for ($i = 0; $i < $count; $i++) {
array_splice($arr1, 3, 0, $arr2);
}
You are on the right track, but you need make the splice point ($i+1)*3, and only splice in the $arr2[$i] value, not the entire array. Also you need to work backwards from the end as inserting values into the array causes the indexes to change.
$arr1 = array('1', '2', '3', '4', '5', '6', '7');
$arr2 = array('a', 'b', 'c', 'd', 'e');
$count = ceil(count($arr1) / 3) - 1;
for ($i = $count - 1; $i >= 0; $i--) {
array_splice($arr1, ($i + 1) * 3, 0, $arr2[$i]);
}
print_r($arr1);
Output:
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => a
[4] => 4
[5] => 5
[6] => 6
[7] => b
[8] => 7
)
Note that dependent on the result you want to achieve when $arr1 is a multiple of 3 elements, you may want to change
$count = ceil(count($arr1) / 3) - 1;
to
$count = ceil((count($arr1) + 1) / 3) - 1;
You can just insert element of $arr2 ervey 3 element2 of $arr1, Demo
$result = [];
foreach($arr1 as $key => $value){
$result[] = $value;
if((0 == ($key + 1) % 3) && isset($arr2[($key + 1)/3-1])){
$result[] = $arr2[($key + 1)/3-1];
}
}
print_r($result);
a twice. You probably mean $result[] = $arr2[intval(($key + 1) / 3) - 1];At every third index, splice in a member of your other array. Note the original array changes in size, so we need to adjust inserted key accordingly upon each splice.
<?php
for($i=3, $s=0, $c=count($arr1); $i<$c; $i+=3, $s++) {
array_splice($arr1, $i+$s, 0, $arr2[$s]);
}
var_export($arr1);
Output:
array (
0 => '1',
1 => '2',
2 => '3',
3 => 'a',
4 => '4',
5 => '5',
6 => '6',
7 => 'b',
8 => '7',
)
Same omitting the statement of the loop
for(
$i=3, $s=0, $c=count($arr1);
$i<$c;
array_splice($arr1, $i+$s, 0, $arr2[$s++]), $i+=3
);
