How to call a method on an item that you're formatting inside a string in python?-CodePudding

'aBcDe'.lower() works fine and returns 'abcde'.

So why can't I do this : '{0.lower()}'.format('aBcDe') ?

It returns the following error: AttributeError: 'str' object has no attribute 'lower()'

My guess is that the code figures out that the attribute is the entire string 'lower()', instead of 'lower' and it just doesn't work. So how can I call a method in this fashion?

CodePudding user response：

You're right; Python thinks that .lower() is an attribute of the string 'aBcDe'. You can fix this by moving the call to .lower() to the parameter to .format():

'{0}'.format('aBcDe'.lower())

CodePudding user response：

With the format method, you can't put something you want to evaluate inside the curly braces. Here are two (of several ways around this):

'{0}'.format('aBcDe'.lower())

or use an f-string:

f"{'aBcDe'.lower()}"