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PHP array_slice() function definition and usage
- 巴扎黑Original
- 2017-05-26 16:12:581667browse
Definition and usage
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)
Syntax
array_slice(array,start,length,preserve)
Parameters Description
array Required. Specifies an array.
start Must have. numerical value. Specifies the starting position of the element to be retrieved. 0 = first element.
If the value is set to a positive number, it will be taken from front to back.
If the value is set to a negative number, the absolute value of start will be taken from back to front. -2 means start from the second to last element of the array.
length Optional. numerical value. Specifies the length of the returned array.
If the value is set to an integer, this number of elements is returned.
If this value is set to a negative number, the function will terminate fetching this far from the end of the array.
If this value is not set, all elements starting from the position set by the start parameter to the end of the array are returned.
preserve Optional. Specifies whether the function retains key names or resets key names. Possible value:
True -Reserved key name
false -default. Reset key name
Return value: Returns the selected part in the array.
Instance 1:
<!DOCTYPE html><html><body>
<?php
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,1,2));
?>
</body>
</html>Run result:
Array ( [0] => green [1] => blue )
Instance 2:
Use negative start parameter:
<!DOCTYPE html><html><body>
<?php
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,-2,1));
?>
</body></html>Run result:
Array ( [0] => yellow )
Example 3:
Set the preserve parameter to true:
<!DOCTYPE html>
<html>
<body>
<?php
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,1,2,true));
?>
</body>
</html>Run result:
Array ( [1] => green [2] => blue )
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