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Python Functional Python The Lambda Lambada Reduce

Sahar Nasiri
Sahar Nasiri
7,454 Points
Posted by Sahar Nasiri
Sahar Nasiri
7,454 Points

not books

What is different between not books and books in None? Why did Kenneth use not books?

2 Answers

Alexander Davison
Alexander Davison
65,469 Points
Alexander Davison
Alexander Davison
65,469 Points

Wait do you mean "blocks"?

Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

No! I mean the books he wrote in the video! Here's the code:

def long_total(a=None, b=None, books=None):
    if a is None and b is None and books is None:
        return None
    if a is None and b is None and books is not None:
        a = books.pop(0)
        b = books.pop(0)
        return long_total(a, b, books)
    if a is not None and b is None and books and books is not None:
        b = books.pop(0)
        return long_total(a, b, books)
    if a is not None and b is not None and books is not None:
        return long_total(a+b, None, books)
    if a is not None and b is not None and not books:
        return long_total(a+b, None, None)
    if a is not None and b is None and not books or books is None:
        return a
print(long_total(None, None, [b.price for b in BOOKS]))
Ross Coe
Ross Coe
5,061 Points
Ross Coe
Ross Coe
5,061 Points

not books means there is no books left - all values have been popped.. what's confusing is how an empty list is not None.. I'm asking about that