The difference between php associative array and index array

The difference between php associative array and index array

Index array

Arrays with numbers as key names are generally called index arrays. An array whose keys are represented by strings is an associative array that will be introduced below. The keys of the index array are integers and start from 0 and so on.

Index array initialization example:

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Running result:

Array
(
    [0] => 苹果
    [1] => 香蕉
)

Three assignment methods for index array:

1.array[0]='苹果';
2.$arr=array('0'=>'苹果');
3.$arr=array('苹果');

Example:

'苹果');  
if( isset($arr) ) {print_r($arr);}  
?>

You can use for and foreach to access the elements in the array, because for is easier. Here are just examples of using foreach,

$value){  
    echo '
第'.$key.'值是：'.$value;  
}  
  
?>

Running results:

第0值是：苹果
第1值是：香蕉
第2值是：菠萝

Note: Here $key is the key The value $value is the element value

Associative array

In fact, the difference between associative array and index array is only in the key value. The key value of associative array is a string. And it is an artificial regulation, for example:

'橘子');  
echo $fruit['orange'];  
?>

The remaining initialization, assignment, and foreach usage are basically the same.

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