PHP Array function sequence Array_keys ()-Get array key name _php tips

Source: Internet
Author: User
Array_keys () Definition and usage
The Array_keys () function returns a new array containing all the key names in the array.

If the second argument is provided, only the key name with the value is returned.

If the strict parameter is specified as true, PHP uses strict equality comparisons (= = =) to strictly check the data type of the key value.

Grammar
Array_keys (Array,value)
Parameter description
Array required. A specified array of inputs.
Value is optional. The index (key) of the specified value.
Strict optional. Used with the value parameter. Possible values:

True-Returns the key name with the specified value, based on the type.
False-default value. Not dependent on type.


Example 1
Copy Code code as follows:

<?php
$a =array ("a" => "horse", "B" => "Cat", "C" => "Dog");
Print_r (Array_keys ($a));
?>

Output:

Array ([0] => a [1] => b [2] => c)
Example 2
Use the value parameter:
Copy Code code as follows:

<?php
$a =array ("a" => "horse", "B" => "Cat", "C" => "Dog");
Print_r (Array_keys ($a, "Dog"));
?>

Output:

Array ([0] => C)
Example 3
Use the strict parameter (false):
Copy Code code as follows:

<?php
$a =array (10,20,30, "10");
Print_r (Array_keys ($a, "ten", false));
?>

Output:

Array ([0] => 0 [1] => 3)
Example 4
Use the strict parameter (true):
Copy Code code as follows:

<?php
$a =array (10,20,30, "10");
Print_r (Array_keys ($a, "ten", true));
?>

Output:

Array ([0] => 3)

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.