Is a variable inside a variable?

Question

$ bookA = "123"; $ crack = "A";

I want to do something similar to this:

echo $book$crack;

For output 123 .

What is the correct syntax for the echo command?

Thank.

Answer 1

echo ${"book" . $crack};

Answer 2

They are called variable variables , but you should use arrays instead.

Answer 3

$varname = 'book'.$crack;
echo $$varname;

Answer 4

, .

:

$book = array();
$book["A"] = "Some Book";
$crack = "A";

//Later
echo $book[$crack];

Answer 5

:

$bookA = "123";
$crack = "A";
$var = "book$crack";
echo $$var;