Detailed explanation of some functions of php
This article mainly shares with you the detailed explanation of some functions of PHP, mainly in the form of code. I hope it can help you.
1. array_diff_assoc($arr1,$arr2,$arr3...) function: compare the key names and key values of two arrays and return the difference set
Example:
<?php $a1=array("2"=>"this_2","3"=>"this_3","4"=>"this_4","5"=>"this_5"); $a2=array("1"=>"this_1","2"=>"this_2","3"=>"this_3"); $result1 = array_diff_assoc($a1,$a2); //数组可以交换顺序滴,也可以是多个数组 var_dump($result1); ?>
Print results:
array (size=2) 4 => string 'this_4' (length=6) 5 => string 'this_5' (length=6)
2. array_keys() function: Return a new array containing all the key names in the array
Example:
<?php $a1=array("2"=>"this_2","3"=>"this_3","4"=>"this_4","5"=>"this_5"); $result2 = array_keys($a1); var_dump($result2); ?>
Print Result:
array (size=4) 0 => int 2 1 => int 3 2 => int 4 3 => int 5
3. array_key_exists() function: Check whether the specified key name exists in an array. If the key name exists, it returns true. If the key name does not exist, it returns false.
Example:
<?php $a1=array("2"=>"this_2","3"=>"this_3","4"=>"this_4","5"=>"this_5"); if (key_exists("2",$a1)){ echo "yes!"; }else{ echo "no!"; } ?>
Output result:
yes!
4. sort() function: Sort the array in ascending order
5. rsort() function: Sort the array in descending order
6. asort() function: Sort the associative array in ascending order according to the value
7. ksort() function: Sort the associative array in ascending order according to the key Sorting
8. arsort() function: Sort the associative array in descending order according to the value
9. krsort() function: Sort the associative array in descending order according to the key
10. count() function: returns the number of elements in the array
Example:
<?php $a1=array("2"=>"this_2","3"=>"this_3","4"=>"this_4","5"=>"this_5"); $result3 = count($a1); echo $result3; ?>
Output result:
4
Related recommendations:
Advanced explanation of php functions
Introduction to PHP function examples
Search performance test of php functions
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