php array diff recursive

array_diff_assoc

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

array_diff_assoc — Computes the difference of arrays with additional index check

Description

Compares array against arrays and returns the difference. Unlike array_diff() the array keys are also used in the comparison.

Parameters

The array to compare from

Arrays to compare against

Return Values

Returns an array containing all the values from array that are not present in any of the other arrays.

Examples

Example #1 array_diff_assoc() example

The above example will output:

Example #2 array_diff_assoc() example

The above example will output:

Notes

Note: Ensure you pass arguments in the correct order when comparing similar arrays with more keys. The new array should be the first in the list.

See Also

User Contributed Notes 18 notes

Works more like the original function:

an earlier post for recursive array_diff_assoc failed because isset returned false on an array element containing a null value. I updated the code so it compares null values too.

If you’re looking for a true array_diff_assoc, comparing arrays to determine the difference between two, finding missing values from both, you can use this along with array_merge.

print_r(array_diff_assoc($b,$a));
// returns
array
(
[d] => 4
)

print_r(array_merge(array_diff_assoc($a,$b),array_diff_assoc($b,$a)));
// returns
array
(
[c] => 3
[d] => 4
)

The following will recursively do an array_diff_assoc, which will calculate differences on a multi-dimensional level. This not display any notices if a key don’t exist and if error_reporting is set to E_ALL:

The direction of the arguments does actually make a difference:

To diff between n-dimensional array, juste use this :

To unset elements in an array if you know the keys but not the values, you can do:

array_diff_assoc can also be used to find the duplicates in an array

NOTE: the diff_array also removes all the duplicate values that match to the values in the second array:

// yields: array(«b»,»c») the duplicate «a» values are removed
?>

Recursive implementation accepting multiple n-level-arrays as parameters:

For recursive diff of multiple arrays, exending solution provided by Gosh.

Yet another recursive implementation, without if-else hell and with multiple parameters just like the original.

Источник

array_diff

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

array_diff — Вычислить расхождение массивов

Описание

Список параметров

Массивы, с которыми идёт сравнение

Возвращаемые значения

Примеры

Пример #1 Пример использования array_diff()

Пример #2 Пример использования array_diff() с несовпадающими типами

$source = [new S ( ‘a’ ), new S ( ‘b’ ), new S ( ‘c’ )];
$filter = [new S ( ‘b’ ), new S ( ‘c’ ), new S ( ‘d’ )];

Примечания

Смотрите также

User Contributed Notes 27 notes

array_diff(A,B) returns all elements from A, which are not elements of B (= A without B).

You should include this in the documentation more precisely, I think.

array_diff provides a handy way of deleting array elements by their value, without having to unset it by key, through a lengthy foreach loop and then having to rekey the array.

If you want a simple way to show values that are in either array, but not both, you can use this:

I´ve been looking for a array_diff that works with recursive arrays, I´ve tried the ottodenn at gmail dot com function but to my case it doesn´t worked as expected, so I made my own. I´ve haven´t tested this extensively, but I´ll explain my scenario, and this works great at that case 😀

We got 2 arrays like these:

I realy hopes that this could help some1 as I´ve been helped a lot with some users experiences. (Just please double check if it would work for your case, as I sad I just tested to a scenario like the one I exposed)

I just came upon a really good use for array_diff(). When reading a dir(opendir;readdir), I _rarely_ want «.» or «..» to be in the array of files I’m creating. Here’s a simple way to remove them:

If you just need to know if two arrays’ values are exactly the same (regardless of keys and order), then instead of using array_diff, this is a simple method:

?>

The function returns true only if the two arrays contain the same number of values and each value in one array has an exact duplicate in the other array. Everything else will return false.

my alternative method for evaluating if two arrays contain (all) identical values:

?>

may be slightly faster (10-20%) than this array_diff method:

?>

but only when the two arrays contain the same number of values and then only in some cases. Otherwise the latter method will be radically faster due to the use of a count() test before the array_diff().

Also, if the two arrays contain a different number of values, then which method is faster will depend on whether both arrays need to be sorted or not. Two times sort() is a bit slower than one time array_diff(), but if one of the arrays have already been sorted, then you only have to sort the other array and this will be almost twice as fast as array_diff().

Basically: 2 x sort() is slower than 1 x array_diff() is slower than 1 x sort().

It’s important to note that array_diff() is NOT a fast or memory-efficient function on larger arrays.

In my experience, when I find myself running array_diff() on larger arrays (50+ k/v/pairs) I almost always realize that I’m working the problem from the wrong angle.

Typically, when reworking the problem to not require array_diff(), especially on bigger datasets, I find significant performance improvements and optimizations.

If you’re not getting a count(array_diff($a1,$a2))>0 with something similar to the following arrays should use the php.net/array_diff_assoc function instead.

There is more fast implementation of array_diff, but with some limitations. If you need compare two arrays of integers or strings you can use such function:

10x faster than array_diff

Here is some code to take the difference of two arrays. It allows custom modifications like prefixing with a certain string (as shown) or custom compare functions.

I always wanted something like this to avoid listing all the files and folders you want to exclude in a project directory.

$relevantFiles = array_diff(scandir(‘somedir’), array(‘.’, ‘..’, ‘.idea’, ‘.project));

As touched on in kitchin’s comment of 19-Jun-2007 03:49 and nilsandre at gmx dot de’s comment of 17-Jul-2007 10:45, array_diff’s behavior may be counter-intuitive if you aren’t thinking in terms of set theory.

array_diff() returns a *mathematical* difference (a.k.a. subtraction) of elements in array A that are in array B and *not* what elements are different between the arrays (i.e. those that elements that are in either A or B but aren’t in both A and B).

Drawing one of those Ven diagrams or Euler diagrams may help with visualization.

As far as a function for returning what you may be expecting, here’s one:

Resubmitting. the update for takes into account comparison issues

Computes the difference of all the arrays

I’ve found a way to bypass that. I had 2 arrays made of arrays.
I wanted to extract from the first array all the arrays not found in the second array. So I used the serialize() function:

Yes you can get rid of gaps/missing keys by using:

Note that array_diff is not equivalent to

The difference is made only on the first level. If you want compare 2 arrays, you can use the code available at https://gist.github.com/wrey75/c631f6fe9c975354aec7 (including a class with an function to patch the array)

Here the basic function:

A simple multidimentional key aware array_diff function.

Based on one lad’s code, I created following function for creating something like HTML diff. I hope it will be useful.

Hi!
I tried hard to find a solution to a problem I’m going to explain here, and after have read all the array functions and possibilities, I had to create what I think should exist on next PHP releases.

What I needed, it’s some kind of Difference, but working with two arrays and modifying them at time, not returning an array as a result with the diference itself.

so basically, I wanted to delete coincidences on both arrays.

Now, I’ve some actions to do, and I know wich one I’ve to do with the values from one array or another.
With the normal DIFF I can’t, because if I’ve an array like C=1,4, I dont know if I’ve to do the Action_A with 1 or with 4, but I really know that everything in A, will go to the Action_A and everithing in B, will go to Action_B. So same happens with 4, don’t know wich action to apply.

So a call to this will be somethin’ like:

Now, why I use it precisely?

Imagine you’ve some «Events» and some users you select when create the event, can «see» this event you create. So you «share» the event with some users. Ok?

Imagine you created and Event_A, and shared with users 1,2,3.

Now you want to modify the event, and you decide to modify the users to share it. Imagine you change it to users 2,3,4.

(numbers are users ID).

So you can manage when you are going to modify, to have an array with the IDs in DDBB ($original), and then, have another array with ID’s corresponding to the users to share after modifying ($new). Wich ones you’ve to DELETE from DDBB, and wich ones do you’ve to INSERT?

If you do a simple difference or somehow, you get somethin’ like C=1,4.
You have no clue on wich one you’ve to insert or delete.

But on this way, you can know it, and that’s why:

I hope you find it useful, and I encourage PHP «makers», to add in a not distant future, somethin’ like this one natively, because I’m shure that I’m not the first one needing something like this.

Источник

Why array_diff() gives Array to string conversion error?

I get array to string conversion error for the following line:

9 Answers 9

One of your arrays is multidimensional.

Yes, the strict answer is because «One of your arrays is multidimensional.»

All these options will compare the entire array tree, not just the top level.

Since array_diff can only deals with one dimension, you can either:

convert your multi-dimentional array into one dimension, e.g. by:

According to PHP documentation for the function

So it looks like you can’t use this function with multi dimensional array, or in fact any value that cannot be converted to a string. This is because the function will cast values to a string to do the comparison.

This is my solution for a similar problem. I want to compare two associative arrays and return the changed values, but some of the elements are arrays. So if I use

, it gives me «Array to string error». My function will also compare the elements which are arrays and if there’s a difference, it will return the array element. It is still a work in progress and not tested extensively. For example:

if you run ::test it will return:

I’ve got the same error and found the following bug report for php:

Some of the array_* functions that compare elements in multiple arrays do so by (string)$elem1 === (string)$elem2.

Two examples of functions that can throw this are array_intersect() and array_diff().

If these functions are not expected to take arrays with other arrays as values, this should be mentioned on the documentation pages.

That report describes, why php throws an error on comparing a multi-dimensional array.

Источник

PHP: array_diff() function

PHP: Computes the difference of arrays

The array_diff() function is used to compares an array against one or more other arrays and returns the values in the first array that are not present in any of the other arrays.

Version:

Syntax:

Parameter:

Return value:

An array containing all the entries from array1 whose values are not present in any of the other arrays i.e. array2, array3 etc.

Value Type: Array

Example:

Pictorial Presentation:

Practice here online:

See also

Previous:array_diff_ukey
Next: array_fill

PHP: Tips of the Day

PHP: Showing all errors and warnings

Display errors could be turned off in the php.ini or your Apache configuration file.

You can turn it on in the script:

You should see the same messages in the PHP error log.

Источник

array_diff_assoc

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

array_diff_assoc — Вычисляет расхождение массивов с дополнительной проверкой индекса

Описание

Список параметров

Массивы для сравнения

Возвращаемые значения

Примеры

Пример #1 Пример использования array_diff_assoc()

Результат выполнения данного примера:

Пример #2 Пример использования array_diff_assoc()

Результат выполнения данного примера:

Примечания

Замечание: Убедитесь, что передаёте аргументы в правильном порядке, когда сравниваете схожие массивы с большим количеством ключей. Новый массив должен быть первым.

Смотрите также

User Contributed Notes 18 notes

Works more like the original function:

an earlier post for recursive array_diff_assoc failed because isset returned false on an array element containing a null value. I updated the code so it compares null values too.

If you’re looking for a true array_diff_assoc, comparing arrays to determine the difference between two, finding missing values from both, you can use this along with array_merge.

print_r(array_diff_assoc($b,$a));
// returns
array
(
[d] => 4
)

print_r(array_merge(array_diff_assoc($a,$b),array_diff_assoc($b,$a)));
// returns
array
(
[c] => 3
[d] => 4
)

The following will recursively do an array_diff_assoc, which will calculate differences on a multi-dimensional level. This not display any notices if a key don’t exist and if error_reporting is set to E_ALL:

The direction of the arguments does actually make a difference:

To diff between n-dimensional array, juste use this :

To unset elements in an array if you know the keys but not the values, you can do:

array_diff_assoc can also be used to find the duplicates in an array

NOTE: the diff_array also removes all the duplicate values that match to the values in the second array:

// yields: array(«b»,»c») the duplicate «a» values are removed
?>

Recursive implementation accepting multiple n-level-arrays as parameters:

For recursive diff of multiple arrays, exending solution provided by Gosh.

Yet another recursive implementation, without if-else hell and with multiple parameters just like the original.

Источник