CODEWITHSUNDEEP
python
David542
David542

Reputation: 110382

How to get the string literal of a variable

I have a bunch of variables, and I need to get the name of the variable being set for validation. For example:

studio = 'Warner Brothers'
movie = ''
validation = [studio, movie]

validation_errors = []
for item in validation:
    if not item:
        validation_errors.append(name of variable)

In the above case, I'd want the result to be: 

validation_errors = ['movie']

Is there a simple way to do this without building a dict?

Upvotes: 0

Views: 739

Answers (3)

Ethan Furman
Ethan Furman

Reputation: 69170

Does it count if Python builds the dict for you?

studio = 'Warner Brothers'
movie = ''
validation = ['studio', 'movie']

validation_errors = []
for item in validation:
    if not locals()[item]:
        validation_errors.append(item)

However, just building the dict yourself is the better idea.

studio = 'Warner Brothers'
movie = ''
validation = dict(studio=studio, movie=movie)

validation_errors = []
for var, value in validation.items():
    if not value:
        validation_errors.append(var)

And if you want to make a function out of it:

def validate(**vars):
    errors = []
    for var, value in vars.items():
        if not value:
            errors.append(var)
    return errors

-->studio = 'Warner Brothers'
-->movie = ''
-->print validate(studio=studio, movie=movie)
['movie']

Upvotes: 0

John Gaines Jr.
John Gaines Jr.

Reputation: 11544

As an example of how NOT to do it (or maybe as a demonstration of why not to do it), try this code:

def nameof(thing):
    i = id(thing)
    names = [n for n in globals().keys() if id(globals()[n]) == i]
    for name in names:
        if name[0] != '_':
            return name, names
    return names[0], names

It sort of works, though only if the thing you pass it is a global, or has something in the the globals that looks like it. It will also return all sorts of odd matches due to string interning and such.

Upvotes: 0

Josh Lee
Josh Lee

Reputation: 177715

Don’t hurt yourself. Use a dictionary. Simple is better than complex.

validation = {'studio': studio, 'movie': movie}
validation_errors = []
for key in validation:
    if not validation[key]:
        validation_errors.append(key)

If you find yourself wanting to use the local namespace like a dictionary, 99% of the time you just want a dictionary.

Upvotes: 6

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