Python Tuples: remove the first three elements cleanly

My issues:

• How is (9,) different from (9)? (9,)==(9) yields False
• Why is (9,) showing up in the snippet below?
• How do I fix the code below so I get (9)?

chop_first_three = lambda t: t[3:]
chop_first_three((1, 2, 3, 4, 5))  # (4, 5) correct
chop_first_three(('abc', 7, 8, 9)) # (9,)   ??? why not (9)?

Answer

The simple answer is, parentheses are overloaded for grouping and for tuples. To differentiate these forms in python, a trailing comma explicitly indicates a tuple.

Several answers and comments below point this out.

I’ve left my original questions above so the answers below make sense, but obviously, some of my original questions were incorrect.

Answer

In python if you wrap an object in parenthesis you will just get the element back.

a = (9)
print(type(a)) # <class 'int'>

(9,) instead is a tuple containing only one element (the number 9)

a = (9,)
print(type(a)) # <class 'tuple'>

When you slice a tuple you will always get a tuple back (even if it only contains one element) Therefore the (9,)