PHP Delete an array of element instance programs _php Tutorial

In PHP array of quantum mechanics a very useful array type, let me summarize some of the various methods to delete array elements, delete the elements in the array, the first idea is to use the unset function, it can be deleted, but it may be later operation of the array when the problem occurs.

Use the following example to illustrate:

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$arr = Array (0, 1, 2, 3, 4); $index = 2; Unset ($arr [$index]); echo count ($arr); if (Empty ($arr [$index])) { echo "arr[$index] is empty"; } Print_r ($arr); The output is: 4 ARR[2] is empty Array ([0] = 0 [1] = 1 [3] = 3 [4] = =

4) from the above output can see the length of the array is normal, but the subscript remains the original, so follow the subscript to get the element will be problematic. In addition, this method is safe for arrays of key-value forms.

How to safely remove elements? You can use the Array_splice function. The purpose of Array_splice () is to delete the series of elements specified in the original array and replace them with other values (if specified), and the returned value is the deleted element.

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$arr = Array (0, 1, 2, 3, 4); $rtn = Array_splice ($arr, 2, 1); echo count ($arr); Print_r ($arr); Print_r ($RTN); The output is: 4 Array ([0] = 0 [1] = 1 [2] = 3 [3] = 4) Array ([0] = =

2) If you want to get an array after removing the first element, you can have two methods:

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1. $arr = Array (0, 1, 2, 3, 4); Array_splice ($arr, 0, 1); 2. $arr = Array (0, 1, 2, 3, 4); $arr = Array_splice ($arr, 1);

There is also the Array_shift () function to delete the first element in the array and return the value of the deleted element.

The relative Array_pop () function deletes the last element in the array.

The Array_pop () function deletes and returns the last element of the array. The form is:

Mixed Array_pop (Aray target_array);

The following example removes the last state from the $states array:

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$fruits = Array ("Apple", "banana", "orange", "pear"); $fruit = Array_pop ($fruits); $fruits = Array ("Apple", "banana", "orange"); $fruit = "Pear";

Array_filter () to delete empty elements in an array

Function name: Array_filter ()
Call mode: Array_filter ($array)
Parameter description: $array is the object of the operation, we will delete the empty element in it
Instance:

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$array = (' a ' + = ' abc ', ' B ' + = ' bcd ', ' c ' = ' CDE ', ' d ' and ' Def ', ' e ' = ' = ') '; Array_filter ($array); echo " "; Print_r ($array); ?> Results: Array ( [A] = ABC [B] = BCD [C] = CDE [d] = def )

Several functions used to feel array_search () more practical

The Array_search () function, like In_array (), looks for a key value in the array. If the value is found, the key name of the matching element is returned. Returns false if not found

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$array = Array (' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 '); $del _value = 3; Unset ($array [Array_search ($del _value, $array)]);//use unset to delete this element Print_r ($array); Output Array (' 1 ', ' 2 ', ' 4 ', ' 5 ');

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