Question

Hi, I have a query about problem 5 on Quiz 1. The solution says:
v1 = v1[:]
v2 = v2[:] at the beginning.
Can anyone explain to me why we need to do this?
Thanks

Answer 1

post the complete problem/solution
that would prevent the original list object from being mutated. are v1 and v2 function arguments?

copy = original[:] is a way to copy a list, it creates a completely new list object and assigns it to the variable on the left side of the equal sign

http://henry.precheur.org/python/copy_list
http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#other-languages-have-variables
http://effbot.org/pyfaq/how-do-i-copy-an-object-in-python.htm

it helps to reference the course you are taking - ppl taking OCW 6.00 (2008) and OCW 6.00c (2011) and sometimes the edX 6.00 post here - same basic course with similar problems and different pset numbers.

please use a code pasting site to post code:

- http://dpaste.com
- http://pastebin.com
- https://gist.github.com/
- http://pastie.org
- http://codepad.org
- http://ideone.com
- http://www.repl.it/

paste your code there and post the link here. select Python syntax highlighting when u paste.

Answer 2

Thanks very much. I see the point and I will post questions more clearly next time.