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pythonstringvariables

How to get the value of a variable given its name in a string?

For simplicity this is a stripped down version of what I want to do:

def foo(a):
    # I want to print the value of the variable
    # the name of which is contained in a

I know how to do this in PHP:

function foo($a) {
    echo $$a;
}

global $string = "blah"; // might not need to be global but that's irrelevant
foo("string"); // prints "blah"

Any way to do this?

Solution

  • If it's a global variable, then you can do:

    >>> a = 5
>>> globals()['a']
5

    A note about the various "eval" solutions: you should be careful with eval, especially if the string you're evaluating comes from a potentially untrusted source -- otherwise, you might end up deleting the entire contents of your disk or something like that if you're given a malicious string.

    (If it's not global, then you'll need access to whatever namespace it's defined in. If you don't have that, there's no way you'll be able to access it.)