当extract（）用于具有默认键值（0,1,2，...）的数组时会发生什么

Question

I haven't given this much thought before but recently tried an sample code to c what happens when using extract() on an array with default key values, how is it supposed to work there.

    $testArray = array("apple", "ant", "book", "bag");
    extract($testArray);

    print_r($testArray);

    echo "${1}";

where will be the values apple, ant, book, and bag stored after extract() is applied.

This is a simple question but somebody please help me solve it.

Answer 1

As it is in your code it would not create any variables because there are not defined keys so the keys are 0, 1, 2... therefore, invalid variable names that will prevent them from being extracted.

if you use EXTR_PREFIX_ALL or EXTR_PREFIX_INVALID to prefix your keys with something to make them valid variable names then you could see them in

echo $whateveryourprefixis0; 
echo $whateveryourprefixis1; 
echo $whateveryourprefixis2; 
...