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PHP array function sequence array_slice() - remove a value from the array based on conditions and return it

高洛峰
高洛峰Original
2016-12-28 15:16:461908browse

array_slice() definition and usage

The array_slice() function removes a segment of value from the array based on conditions and returns it.

Note: If the array has string keys, the returned array will retain the key names. (See example 4)

grammar
array_slice(array,offset,length,preserve) parameter description
array required. Specifies the input array.
offset is required. numerical value. Specifies the starting position of the element to be retrieved.

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

length is optional. numerical value. Specifies the length of the returned array.

If it is a negative number, select the absolute number of elements of the value from back to front. If the value is not set, all elements are returned.

preserve is optional. Possible values:

true - reserved key
false - default - reset key

Example 1

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

Output:

Array ( [0] => Cat [1] => Horse ) Example 2
With a negative offset parameter:

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

Output:

Array ( [0] => Horse ) Example 3
The preserve parameter is set to true:

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

Output:

Array ( [1] => Cat [2] => Horse ) Example 4
With string key:

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

Output:

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


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