PHP get array intersection and difference set method, PHP get array intersection _php tutorial

PHP obtains the array intersection and the difference set method, PHP obtains the array intersection

This article describes how PHP obtains array intersection and difference sets. Share to everyone for your reference. The specific analysis is as follows:

First, the intersection of the array array_intersect ()

The Array_intersect () function returns an array that retains the key, which consists only of the values that appear in the first array and that appear in each of the other input arrays. The form is as follows:

Array array_intersect (array Array1,array array2[,arrayn ...])

The following example returns all the fruits that appear in the $fruit1 array and also appear in $fruit2 and $fruit3:

<?php$fruit1 = Array ("Apple", "Banana", "Orange"), $fruit 2 = Array ("Pear", "Apple", "Grape"), $fruit 3 = Array (" Watermelon "," Orange "," Apple "), $intersection = Array_intersect ($fruit 1, $fruit 2, $fruit 3);p Rint_r ($intersection);// output//Array ([0] = Apple)?>

The Array_intersect () function considers them to be the same only if the two elements are equal and have the same data type.

Intersection of associative arrays ARRAY_INTERSECT_ASSOC ()

The function Array_intersect_assoc () is basically the same as Array_intersect () except that he also considers the keys of the array in the comparison. Therefore, only key/value pairs that appear in the first array and in all other input arrays are returned to the result array.

The form is as follows:

Array Array_intersect_assoc (array Array1,array array2[,arrayn ...])

The following example returns all the key/value pairs that appear in the $fruit1 array and also in $fruit2 and $fruit3:

<?php$fruit1 = Array ("Red" = "Apple", "yellow" = "Banana", "orange" = "orange"), $fruit 2 = Array ("Yellow" = > "Pear", "Red" and "Apple", "Purple" and "Grape"); $fruit 3 = Array ("green" = "watermelon", "orange" + "orange" "Red" = "Apple"), $intersection = Array_intersect_assoc ($fruit 1, $fruit 2, $fruit 3);p Rint_r ($intersection);// output//Array ([red] = Apple)?>

Second, the difference set of the array Array_diff ()

The function Array_diff () returns a value that appears in the first array but not in the other input array. This function is opposite to Array_intersect ().

Array Array_diff (array Array1,array array2[,arrayn ...])

Examples are as follows:

<?php$fruit1 = Array ("Apple", "Banana", "Orange"), $fruit 2 = Array ("Pear", "Apple", "Grape"), $fruit 3 = Array (" Watermelon "," Orange "," Apple "), $intersection = Array_diff ($fruit 1, $fruit 2, $fruit 3);p Rint_r ($intersection);// output//Array ([1] = Banana)?>

The difference set of associative arrays Array_diff_assoc ()

The function Array_diff_assoc () is basically the same as Array_diff (), except that it also considers the keys of the array when compared. Therefore, a key/value pair that appears only in the first array and no longer appears in the other input array is returned to the result array. The form is as follows:

Array Array_diff_assoc (array Array1,array array2[,arrayn ...])

The following example returns only [yellow] + Banana, because this special key/value pair appears in $fruit1 and does not exist in $fruit2 and $fruit3.

<?php$fruit1 = Array ("Red" = "Apple", "yellow" = "Banana", "orange" = "orange"), $fruit 2 = Array ("Yellow" = > "Pear", "Red" and "Apple", "Purple" and "Grape"); $fruit 3 = Array ("green" = "watermelon", "orange" + "orange" "Red" = "Apple"), $intersection = Array_diff_assoc ($fruit 1, $fruit 2, $fruit 3);p Rint_r ($intersection);//output// Array ([yellow] = Banana)?>

I hope this article is helpful to everyone's PHP programming.

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