如何使用PHP以JSON格式打印数据

Question

PHP code :

print_r($InformationRetrieval['KeywordExtraction'][1]);

Outputs :

Array
(
    [google] => 15
    [search] => 18
    [or] => 2
    [web] => 4
    [is] => 4
    [a] => 5
    [engine] => 2
}

but needs to print words that are indexes of this array eg: google, search, or, web etc..

How is it done?

Answer 1

You can use array_keys ;

print_r(array_keys($InformationRetrieval['KeywordExtraction'][2]));

Here is a working demo: Demo

Answer 2

use this :

<?php
$a = array("google" => 15, "search" => 18, "or" => 2, "web" => 4, "is" => 4, "a" => 5, "engine" => 2);

foreach($a as $key=>$value) {
   echo $key;
}
?>