Python Remove last 3 characters of a string

Removing any and all whitespace:

foo = ''.join(foo.split())

Removing last three characters:

foo = foo[:-3]

Converting to capital letters:

foo = foo.upper()

All of that code in one line:

foo = ''.join(foo.split())[:-3].upper()

It doesn't work as you expect because strip is character based. You need to do this instead:

foo = foo.replace(' ', '')[:-3].upper()

>>> foo = "Bs12 3ab"
>>> foo[:-3]
'Bs12 '
>>> foo[:-3].strip()
'Bs12'
>>> foo[:-3].strip().replace(" ","")
'Bs12'
>>> foo[:-3].strip().replace(" ","").upper()
'BS12'