Php uses the array_slice function to obtain a random array or the first few pieces of data.

This article describes how to use the array_slice function in php to obtain random arrays or the first few pieces of data. For more information, see

This article describes how to use the array_slice function in php to obtain random arrays or the first few pieces of data. For more information, see

Let's talk about the basic syntax:

Array_slice (array $ array, int $ offset [, int $ length [, bool $ preserve_keys])

Array_slice () returns a sequence in the array specified by the offset and length parameters.

If offset is not negative, the sequence starts from this offset in array. If offset is negative, the sequence starts from the end of the array.

If length is given and is positive, the sequence will have so many units. If length is given and it is negative, the sequence is terminated so far from the end of the array. If this parameter is omitted, the sequence starts from offset to the end of array.

Note that array_slice () resets the array key by default. Since PHP 5.0.2, you can change this behavior by setting preserve_keys to TRUE.

$ Input = array ("a", "B", "c", "d", "e"); $ output = array_slice ($ input ,); // returns the array returns "c", "d", and "e" $ output = array_slice ($ input,-,) starting with the subscript ,-,); // returns "d" $ output = array_slice ($ input,); // returns "a", "B ", and "c" // note the differences in the array keysprint_r (array_slice ($ input,-); print_r (array_slice ($ input,-, true ));

To return a random number of data records, shuffle ($ input) and array_slice can be used to query the original array.

PS: PHP array_slice () function

Definition and usage

The array_slice () function extracts a value from the Array Based on the Conditions and returns it.

Note: If the array has a string key, the returned array retains the key name. (See example 4)

Syntax

The Code is as follows:

Array_slice (array, offset, length, preserve)

Parameters

Description

Array

Required. Specifies the input array.

Offset

Required. Value. Specifies the start position of the retrieved element.

If it is a positive number, it is taken from the beginning to the end. If it is a negative value, it is taken from the back to the absolute value of the offset.

Length

Optional. Value. Specifies the length of the returned array.

If the length is positive, the number of elements is returned.

If length is negative, the sequence ends so far from the end of the array.

If this parameter is omitted, the sequence starts from offset to the end of array.

Preserve

Optional. Possible values:

· True-reserved key

Example 1

<? Php $ a = array (0 => "Dog", 1 => "Cat", 2 => "Horse", 3 => "Bird "); print_r (array_slice ($ a, 1, 2);?>

Output:

The Code is as follows:

Array ([0] => Cat [1] => Horse)

Example 2

Offset parameter with negative values:

<? Php $ a = array (0 => "Dog", 1 => "Cat", 2 => "Horse", 3 => "Bird "); print_r (array_slice ($ a,-2, 1);?>

Output:

The Code is as follows:

Array ([0] => Horse)

Example 3

Set the preserve parameter to true:

<? Php $ a = array (0 => "Dog", 1 => "Cat", 2 => "Horse", 3 => "Bird "); print_r (array_slice ($ a, 1, 2, true);?>

Output:

The Code is as follows:

Array ([1] => Cat [2] => Horse)

Example 4

String key:

<? Php $ a = array ("a" => "Dog", "B" => "Cat", "c" => "Horse ", "d" => "Bird"); print_r (array_slice ($ a, 1, 2);?>

Output:

The Code is as follows:

Array ([B] => Cat [c] => Horse)

The above section describes how to use the array_slice function in php to obtain random arrays or the first few pieces of data.

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