Reset/remove all values in an array in PHP - php

Question

I have an array_flipped array that looks something like:
{ "a" => 0, "b" => 1, "c" => 2 }
Is there a standard function that I can use so it looks like (where all the values are set to 0?):
{ "a" => 0, "b" => 0, "c" => 0 }
I tried using a foreach loop, but if I remember correctly from other programming languages, you shouldn't be able to change the value of an array via a foreach loop.
foreach( $poll_options as $k => $v )
$v = 0; // doesn't seem to work...
tl; dr: how can I set all the values of an array to 0? Is there a standard function to do this?

Answer 1

$array = array_fill_keys(array_keys($array), 0);
or
array_walk($array, create_function('&$a', '$a = 0;'));

Answer 2

You can use a foreach to reset the values;
foreach($poll_options as $k => $v) {
$poll_options[$k] = 0;
}

Answer 3

array_fill_keys function is easiest one for me to clear the array. Just use like
array_fill_keys(array_keys($array), "")
or
array_fill_keys(array_keys($array), whatever you want to do)
foreach may cause to decrease your performance to be sure that which one is your actual need.

Answer 4

Run your loop like this, it will work:
foreach( $poll_options as $k => $v )
$poll_options[$k] = 0;
Moreover, ideally you should not be able to change the structure of the array while using foreach, but changing the values does no harm.

Answer 5

As of PHP 5.3 you can use lambda functions, so here's a functional solution:
$array = array_map(function($v){ return 0; }, $array);

Answer 6

You have to use an ampersand...
foreach( $poll_options as &$v)
$v = 0;
Or just use a for loop.

Answer 7

you can try this
foreach( $poll_options as $k => &$v )
$v = 0;
Address of $v

Answer 8

array_combine(array_keys($array), array_fill(0, count($array), 0))
Would be the least manual way of doing it.

Answer 9

There are two types for variable assignment in PHP,
Copy
Reference
In reference assignment, ( $a = &$b ), $a and $b both, refers to the same content. ( read manual )
So, if you want to change the array in thesame time as you doing foreach on it, there are two ways :
1- Making a copy of array :
foreach($array as $key=>$value){
$array[$key] = 0 ; // reassign the array's value
}
2 - By reference:
foreach($array as $key => &$value){
$value = 0 ;
}