Adding arrays in php - php

Question

Arrays have been comprehensively covered but am still stumped about how to go around this. I have two arrays which i want to merge without overwriting duplicate keys i.e.
Array1
(
[0] => 0
[1] => 1
[2] => 1
[3] => 1
[4] => 1
[5] => 0
[6] => 0
)
+
Array2
(
[0] => 0
[1] => 0
[2] => 0
[3] => 0
[4] => 0
[5] => 0
[6] => 1
)
my ideal result is
Array1 + Array2
(
[0] => 0
[1] => 1
[2] => 1
[3] => 1
[4] => 1
[5] => 0
[6] => 1
)
How would i do this? I've tried using + but it gives the first array as the result

Answer 1

What you want to do is to map both arrays into single array, containing max value from two respective values, like that:
$array1 = array(0, 1, 1, 1, 1, 0, 0);
$array2 = array(0, 0, 0, 0, 0, 0, 1);
$result = array_map('max', $array1, $array2);
See the result here: http://ideone.com/clone/MN568
It looks like that:
array(7) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(1)
[3]=>
int(1)
[4]=>
int(1)
[5]=>
int(0)
[6]=>
int(1)
}

Answer 2

array_merge() does not overwrite duplicate elements that have numeric keys.

Answer 3

Given the arrays are of the same length:
function bitwise_or_arrays($arr1, $arr2) {
$result = array();
for ($i = 0; $i < count($arr1); $i++) {
$result[$i] = $arr1 | $arr2;
}
return $result;
}

Answer 4

If you are looking for the greater (nonzero) of the two arrays, you can iterate like so:
$array1 = array(1,0,0,1,1,1);
$array2 = array(0,0,1,0,0,1);
$newarr = array();
foreach ($array1 as $k => $v) {
$newarr[$k] = max($array1[$k], $array2[$k]);
}
print_r($newarr);
Array
(
[0] => 1
[1] => 0
[2] => 1
[3] => 1
[4] => 1
[5] => 1
)
If what you need is to add the values, use:
$newarr = array();
foreach ($array1 as $k => $v) {
$newarr[$k] = $array1[$k] + $array2[$k];
}

Answer 5

Just for fun (although in your case with 0 and 1 values it works :)
$array1 = array(0, 1, 1, 1, 1, 0, 0);
$array2 = array(0, 0, 0, 0, 0, 0, 1);
$str1 = implode('', $array1);
$str2 = implode('', $array2);
$result = str_split($str1 | $str2);
Sorry for this variant, I know it's crazy, but just couldn't not to post it. Arrays look like bit masks 0111100 and 0000001. So just using bitwise | operator.
So result:
Array
(
[0] => 0
[1] => 1
[2] => 1
[3] => 1
[4] => 1
[5] => 0
[6] => 1
)

Answer 6

If what your looking is to combine them use array_combine().
$a = array('green', 'red', 'yellow');
$b = array('avocado', 'apple', 'banana');
$c = array_combine($a, $b);
print_r($c);
//*output:
array(
[green] => avocado
[red] => apple
[yellow] => banana
)
here's how to merge array:
$beginning = 'foo';
$end = array(1 => 'bar');
$result = array_merge((array)$beginning, (array)$end);
print_r($result);
//output:
Array(
[0] => foo
[1] => bar
)
heres how to add values
$a = array(0=>1, 1=>2, 2=>3, 3=>4);
$b = array(0=>5, 1=>6, 2=>7, 3=>8);
$c = $a[0] += $b[0];
print_r($c);//output: 6
im not a guru on php but i hope this helps you even just abit.

Answer 7

Just for the fun of it:
$array1 = array(0,1,1,1,1,0,0);
$array2 = array(0,0,0,0,0,0,1);
$array3 = str_split(decbin(bindec(implode('',$array1)) | bindec(implode('',$array2))));
var_dump($array3);
Unfortunately it trims leading zeroes
Using
$array3 = str_split(str_pad(decbin(bindec(implode('',$array1)) | bindec(implode('',$array2))),count($array1),'0',STR_PAD_LEFT));
will restore leading zeroes, but doesn't feel as clean