PHP Common Array function Usage summary, PHP array Summary _php tutorial

PHP Common Array function Usage summary, PHP array Summary

The examples in this article describe common use of array functions in PHP. Share to everyone for your reference, as follows:

1.array Array_merge (Array $array 1 [, Array $array 2 [, $array]])

function function: Merges the cells of one or more arrays, and the values in an array are appended to the previous array. Returns an array of results.

If the input array has the same string key name, the value following the key name overrides the previous value. However, if the array contains numeric key names, subsequent values will not overwrite the original values, but are appended to the back.

If only one array is given and the array is a numeric index, the key name is re-indexed in a sequential manner.

Example 1: An array with the same string key name

$array 1=array (' color ' = ' greed ', ' 3 ' =>8); $array 2=array ("A", ' color ' = "red", ' 3 ' =>8); Var_dump (Array_ Merge ($array 1, $array 2));

Output:

Array (4) {  ["Color"]=> string (3) "Red"  [0]=> Int (8)  [1]=> string (1) "a"  [2]=> int (8)}

The duplicate color of the key name is overwritten, taking only the following value ' red ', while the number key name of the same ' 3 ' is not overwritten, but appended to the back.

2.array array_slice (array $array, int $offset, [, int $length [, bool $preserve _keys]])

function function: Returns a sequence in an array of arrays as specified by the offset and length parameters.

If offset is non-negative: The array starts at the offset from the start side. $array =array (1,2,3,4,5,6); Array_slice ($array, 2); equivalent (3,4,5,6); Red represents the truncated array
If offset is negative: the array starts at the offset from end to offset. Array_slice ($array,-2); equivalent (1,2,3,4,5,6);
If length is positive: the number of intercepts starting with offset. Array_slice ($array, 2,2); equivalent (3,4, 5,6);
If length is negative: the sequence terminates so far away from the end of the array; Array_slice ($array, 2,-1); equivalent (3,4,5, 6);
The default is: to the end of the array.

About the specific use of array_slice can also refer to the previous article "PHP array_slice function usage examples in detail"

3.array_map (callback $callback, array $arr 1[, array $ ...])

function function: Returns an array that contains all the cells in the ARR1 after the callback action. The number of arguments callback accepts should be the same as the number of arrays passed to the Array_map () function.

<?phpfunction Cube ($n) {  return ($n * $n * $n);} $a = Array (1, 2, 3, 4, 5); $b = Array_map ("cube", $a);p rint_r ($b); >

Output:

Array (  [0] = 1  [1] = 8  [2] =  [3] =  [4] = 125)

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I hope this article is helpful to you in PHP programming.

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