=>在php中使用数组时的含义是什么[复制]

Question

This question already has an answer here:

• What does “=>” mean in PHP? 6 answers
• Reference — What does this symbol mean in PHP? 18 answers

I have a php code.

$metadata = Array(
        'facebook'  => Array(
                'title'         => 'og:title',
                'type'          => 'og:type',
                'url'           => 'og:url',
                'thumbnail'     => 'og:image',
                'sitename'      => 'og:site_name',
                'key'           => 'fb:admins',
                'description'   => 'og:description'
            ),
        'google+'   => Array(
                'thumbnail'     => 'image',
                'title'         => 'name',
                'description'   => 'description'
            ),
        'twitter'   => Array(
                'card'          => 'twitter:card',
                'url'           => 'twitter:url',
                'title'         => 'twitter:title',
                'description'   => 'twitter:description',
                'thumbnail'     => 'twitter:image'
            )
    );

what does the => means. How to access an element in this array.

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Answer 1

You have a multi dimensional array, so facebook, google and twitter are elements of the 1st dimension of the $metadata array and they are arrays themselves, here lies the multi dimension.

The => is just like an arrow pointing to the value/data.

To access the 1st dimension would be $metadata['twitter']; or $metadata[2]; it's the same statement, this would bring back the elements/keys of the twitter array.

To access the 2nd dimension would be $metadata['twitter']['card']; or $metadata[2][0]; again the two statements are the same, this would bring back the value of the element/key card