Use of => in PHP

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轮回少年
轮回少年 2020-12-17 18:24

What does this mean in PHP and when is the time to use it?

 =>

Another example.

 foreach ($parent as $task_id => $tod         


        
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  •  野趣味
    野趣味 (楼主)
    2020-12-17 19:11

    To elaborate a bit on what has already been said.

    Assuming that you know about arrays in PHP. Which is really a way of grouping a "list" of items under the same variable given a certain index - normally a numeric integer index starting from 0. Say we want to make a list of the indexes English term, that is,

    Zero
    One
    Two
    Three
    Four
    Five
    

    Representing this in PHP using an array could be done like so:

    $numbers = array("Zero", "One", "Two", "Three", "Four", "Five");
    

    Now, what if we wanted the reverse situation? Having "Zero" as key and 0 as value? Having a non-integer as a key of an array in PHP is called an associative array where each element is defined using the syntax of "key => value", so in our example:

    $numbers = array("Zero" => 0, "One" => 1, "Two" => 2, "Three" => 3, "Four" => 4, "Five" => 5);
    

    The question now becomes: What if you want both the key and the value when using a foreach statement? Answer: the same syntax!

    $numbers = array("Zero" => 0, "One" => 1, "Two" => 2, "Three" => 3, "Four" => 4, "Five" => 5);
    
    foreach($numbers as $key => $value){
        echo "$key has value: $value\n";
    }
    

    This would display

    Zero has value: 0
    One has value: 1
    Two has value: 2
    Three has value: 3
    Four has value: 4
    Five has value: 5
    

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