Using locals() and format() method for strings: are there any caveats?

user_114388 0
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Are there any disadvantages, caveats or bad practice warnings about using the following pattern?

def buildString(user, name = 'john', age=22):
    userId = user.getUserId()
    return "Name: {name}, age: {age}, userid:{userId}".format(**locals())

I had a very repetitive string generation code to write and was tempted to use this, but something about using locals() makes me uncomfortable. Is there any danger of unexpected behavior in this?

Edit: context

I found myself constantly writing stuff like:

"{name} {age} {userId} {etc}...".format(name=name, age=age, userId=userId, etc=etc)
locals local-variables string-formatting python
3 Answers

Pre Python 3.6 answer

This is very old, but if you find yourself using .format the one caveat I have encountered with passing in **locals is that if you don't have that variable defined anywhere, it will break. Explicitly stating what variables are passed in will avoid this in most modern IDEs.

foo = "bar"
"{foo} and {baz} are pair programming".format(**locals())
<exception occurs>
user_10752470
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