I have two arrays: Array ( [0] => 2 [1] => 3 ) and Array ( [0] => 2 ).
I want to get the value, which is not in second array. So I have used the array_diff function but my result will get Array ( [1] => 3 )
Actually this is the result. But a small problem here, its position is (key) 1. I want the result in to a new array starts from 0th position, i.e., Array ( [0] => 3 ).
How can I achieve this?
you can use array_values(array_diff($arr1, $arr2)); if order doesn't matter
You should run array_values() on the result and this would give you a new array with indexes starting at 0.
This is a known shortcoming of array_diff(), check the php docs.
Related
please view the following code with 2 arrays. i use multisort function with sort flags for ascending and numeric then display. as you can see in the output that array 2 starts with 100 when it should be last. please explain what is causing this and how to sort it correctly. thank you.
<?php
$array1 = array(1,7,10,6);
$array2 = array(100,20,25,10);
array_multisort($array1, SORT_ASC, SORT_NUMERIC, $array2);
print_r($array1);
echo "<br>";
print_r($array2);
?>
output:
Array ( [0] => 1 [1] => 6 [2] => 7 [3] => 10 )
Array ( [0] => 100 [1] => 10 [2] => 20 [3] => 25 )
Ah, yes, array_multisort is a bit tricky to understand the first time round.
Basically the sort is lexicographical, a fancy word meaning that the first array is sorted and the second arrays elements are ordered according to the first array.
Look at your first (output) array and see the order and map it to the initial second array and you'll see whats happening.
So the second array you take the 1st, 4th , 2nd and 3rd elements.
If you just want plain sorting for multiple arrays then just do them one by one or over a loop.
I am trying to compare two different arrays and get the values that do not exist in 1 of the arrays. Here are my 2 arrays:
Array ( [0] => 2fbd5868-28ec-418d-854a-0736db720c8a [1] => f4a41974-5373-4862-a5e7-9d28b8c2301f [2] => a1874f68-3da1-47c3-97ef-a68580ce2a52)
Array ( [0] => 2fbd5868-28ec-418d-854a-0736db720c8a [1] => f4a41974-5373-4862-a5e7-9d28b8c2301f [2] => a1874f68-3da1-47c3-97ef-a68580ce2a52 [3] => 583cee91-1913-4e9d-b51d-e27083420001)
As you can see the second array has an additional value. I am trying to user array_diff like this:
$result = array_diff($array1,$array2);
print_r($result);
However the out of the array_diff is:
array()
Any ideas what is going on?
As people have suggested and i have already tested switching the arrays around, this is the output:
Array ( [0] => [1] => )
array_diff gives you the values from $array1 that are not in the other arrays. All the values of your first array are in the second. Sou change the order of your arrays and you should be fine.
See also here: http://php.net/manual/de/function.array-diff.php
The order of arguments in array_diff() is important
Returns an array containing all the entries from array1 that are not
present in any of the other arrays2
Read array_diff
$result = array_diff($array2,$array1);
Try like this
I have two arrays:
$userBuildingIds
print_r():
Array
(
[0] => 4
)
and $allRequiredIds
print_r:
Array
(
[0] => 4
[1] => 1
)
now I want check if one element of $userBuildingIds exists in
the $allRequiredIds array. And if so, I want get a new array of all elements they are NOT in the first array like this:
Array
(
[0] => 1
)
(because 1 isn't in $userBuildingIds)
I try this with array_diff but it gives me this result (with the key of array 2):
Array
(
[1] => 1
)
Is it possible to get an array in which are all the elements of array $allRequiredIds where are not in $userBuildingIds, but without copy the keys from $allRequiredIds?
If you don't care about the keys of the returned array then you can just use array_values() on it to get a new array having the keys starting with 0.
The code will be:
$diffIds = array_values(array_diff($allRequiredIds, $userBuildingIds));
It produces a list of values from $allRequiredIds that does not exist in $userBuildingIds. The returned list has numeric keys starting with 0 (no association with the original keys from $allRequiredIds is $userBuildingIds is kept, on purpose).
i have some problem to understand array_multisort
See how it sorts when two values are the same:
$a1=array("Dog","Dog","Cat");
$a2=array("Pluto","Fido","Missy");
array_multisort($a1,$a2);
print_r($a1);
print_r($a2);
The output of the code above will be:
Array ( [0] => Cat [1] => Dog [2] => Dog )
Array ( [0] => Missy [1] => Fido [2] => Pluto )
let me know why Missy comes first, if you do by ascending it must be
Array ( [0] => Fido, [1] => Missy, [2] => Pluto )
for descending vise versa
also see this
With sorting parameters:
$a1=array("Dog","Dog","Cat");
$a2=array("Pluto","Fido","Missy");
array_multisort($a1,SORT_ASC,$a2,SORT_DESC);
print_r($a1);
print_r($a2);
The output of the code above will be:
Array ( [0] => Cat [1] => Dog [2] => Dog )
Array ( [0] => Missy [1] => Pluto [2] => Fido )
but Array ( [0] => Missy [1] => Pluto [2] => Fido ) not at SORT_DESC is some type of mixed up.
can some one explain me how the array_multisort is working, so that i can understand how it's working.
Well, you're sorting the arrays in a similar way to programs like Excel. Each array corresponds to a column.
First, all arrays are sorted by the first array given. If there are identical values, those affected are sorted by the second array given. If there are again equal values, the third array is used, etc.
Or in other words: The arrays are sorted using all arrays, but beginning on the right (if you assume it really sorts by all columns once).
For your particular example (the second one):
At first you want to sort in ascending order, so Cat will be first. Therefore the last array element will be moved to the first position in both arrays. The other two elements, Dog are equal. This causes the function to look at the next array. It's told to sort this array in descending order, so Pluto comes first. In this case this leads to the result that the elements aren't moved at all (as their order is correct already).
The entries in the second array corresponding to the identical entries in the first array.
If you look at the documentation and the first example, you'll notice that this is the expected behavior.
With two arguments, both arrays: the first array is sorted; the second array will have its corresponding values re-arranged and sorted if the corresponding values in first column tie. As for your example, think of it as you're doing a SQL ORDER BY Animal, Name:
Cat comes first
The two Dogs have a tie so Fido comes first because Fido < Pluto
I've Googled it for two days, and tried looking at the PHP manual, and I still can't remember that function that aligns the key values for PHP arrays.
All I'm looking for is the function that takes this:
Array
(
[0] => 1
[3] => 2
[4] => 3
[7] => 4
[9] => 5
)
And converts it into this:
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)
Basically, the array is first sorted by key (their values attached to them stay with them), then all the keys are set to all the counting numbers, consecutively, without skipping any number (0,1,2,3,4,5,6,7,8,9...). I saw it being used with ksort() a few months ago, and can't see to remember or find this elusive function.
Well, you see, this one is hard, because the general description on the PHP array functions page does not say that this function does what you're looking for.
But you can sort the array using ksort(), and then use this: array_values() . From the page from the PHP manual:
array_values() returns all the values from the input array and indexes numerically the array.
You can use array_merge:
$array = array_merge($array);
It will reindex values with numeric keys.
Update: Using array_values as proposed in #LostInTheCode's answer is probably more descriptive.
function array_reset_index_keys($array)
{
$return = array();foreach($array as $k => $v){$return[] = $v;}return $return;
}
And then use like a regular function, should re index the array
you can also use native functions such as array_values which returns the values of an array into a single dimension array, causing it to be re indexed .