PHP function array_flip() used to reverse/exchange the key names in the array and the corresponding associated key values-PHP Tutorial-php.cn

Example

Reverse the key names in the array and the corresponding associated key values:

"red","b"=>"green","c"=>"blue","d"=>"yellow"); $result=array_flip($a1); print_r($result); ?>

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Definition and usage

array_flip() function is used to reverse/exchange arrays The key name in and the corresponding associated key value.

Syntax

array_flip(array);

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Parameters	Description
array	Required. Specifies the array whose key/value pairs need to be reversed.

Technical details

Return value:	If the inversion is successful, the inversion is returned the array after. If the reversal fails, NULL is returned.
PHP version:	4+

## Note that the value in trans needs to be a legal key name , for example, it needs to be

integerorstring. A warning will be emitted if the value is of the wrong type, and the key/value pair in question will not be reversed.If the same value appears multiple times, the last key name will be used as its value, and all
otherswill be lost.　array_flip() returns FALSE if it fails.
Example:

$hills=array("first"=>"data1″,"second"=>"data2″,"third"=>"data1″); 　　$hills=array_flip($hills); //还原键名 　　$hills1=array_flip(array_flip($hills));//删除重复 　　display $hills1

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The result is:

data2 data1 two data.

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