I have two arrays
$a = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p');
$b = array('1','2','3','3','4','2','1','4','2','2');
Array $a sometimes has more values.
I need to join those two arrays but for result I need to loop values of the array $b as long there are values of the array $a.
Result should be like this
a1
b2
c3
d3
e4
f2
g1
h4
i2
j2
k1 // array $b starts to loop here
l2
m3
n3
o4
p2
Using the modulo (php: %) is awesome for this kind of stuff:
$i = 0;
$count = count($b);
foreach($a as $val1){
echo $val1, $b[$i++ % $count];
// if you don't want to echo, do something else :)
}
As soon as $i reaches $count, $i % $count will start at 0 again.
$i = 0;
$result = array();
foreach ($a as $val) {
if (isset($b[$i])) {
$result[] = $val.$b[$i++];
} else {
$result[] = $val.$b[0];
$i = 1;
}
}
print_r($result);
Here's a version that works no matter what the lengths or the indexes of the two arrays are:
function zip(array $a1, array $a2) {
$a1 = array_values($a1); // to reindex
$a2 = array_values($a2); // to reindex
$count1 = count($a1);
$count2 = count($a2);
$results = array();
for($i = 0; $i < max($count1, $count2); ++$i) {
$results[] = $a1[$i % $count1].$a2[$i % $count2];
}
return $results;
}
This makes $b "loop-over" until it's as big as $a.
<?php
$a = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p');
$b = array('1','2','3','3','4','2','1','4','2','2');
while(count($b) < count($a))
$b = array_merge($b, array_splice($b, 0, count($a) - count($b)));
print_r($a);
print_r($b);
?>
$b is really small)
$a has 100 items and $b has 10 (basically, what if count($a) / count($b) >= 2)?
$a when it's shorter (here you don't need to, but asymmetrical behavior like that in a function is a bug generator), and c) there's really nothing gained by adding all these duplicate elements: you can still write an one-line loop body without doing this. Just some food for thought -- this is an approach I thought about as well :)