PHP array Key-value operations and arrays of statistical functions-functions

1. Array function/function: provides many useful code snippets written by the official, improve the writing speed

1) Array of key-value manipulation functions

Array_values ();//Gets the value in the array

Array_keys ();//Gets the keys in the array

In_array ();//Check if a value is in the array

Array_flip ();//Key and value swap

Array_reverse ();//The values in the array are reversed

Simulation gets the value of key
<?Php$arr=Array ("name"="User1"," Age"=" -","Sex"="nan");foreach($arr as$key =$val) {$keys []=$key; Echo $key."<br>";} Print_r ($keys);?>The result of the operation is Nameagesexarray ([0] = = Name [1] = age [2] = + Sex)

<?php
$arr =array

("Name" = "user1", "age" = "+", "sex" = "Nan");
Print_r (Array_keys ($arr));
?>
When you use a function. Execution results are
Array ([0] = = Name [1] = age [2] = = Sex)
The effect is the same.
In the PHP help document, the brackets indicate that the parameter is optional

2) elements and uniqueness of the statistical array

COUNT ()//number of statistical arrays

array_count_values//the number of duplicate values in the statistics array

array_unique//Remove Duplicates

3) functions for handling arrays using callback functions

Array_filter ()//array value filtering

Array_map ()//function The callback function on the cell of the given array

4) Sorting Functions for arrays

sort//sort the array by value, ascending, not preserving key

rsort//sort the array values by value, descending, not preserving key

asort//sort the array values by value, ascending, preserving the key value

arsort//sort the array values by value, descending, preserving the key value

Ksort ()//key sort

Krsort//key sort

natsort//Natural number Sorting

natcasesort//ignoring case natural number ordering

array_multisort//the sorting of multidimensional arrays

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2. String functions

PHP array Key-value operations and arrays of statistical functions-functions