Re: list comprehension question

Discussion in 'Python' started by Dwight Hutto, Oct 17, 2012.

  1. Dwight Hutto

    Dwight Hutto Guest

    On Tue, Oct 16, 2012 at 10:13 PM, Dave Angel <> wrote:
    > On 10/16/2012 09:54 PM, Kevin Anthony wrote:
    >> I've been teaching myself list comprehension, and i've run across something
    >> i'm not able to convert.
    >>
    >> here's the original code for matrix multiplcation
    >>
    >> retmatrix = Matrix(self.__row,other.__col)
    >> for m in range(0,retmatrix.__row):
    >> for n in range(0,retmatrix.__col):
    >> product = 0
    >> for p in range(1,self.__col+1):
    >> product += (self.__matrix[m][p] * other.__matrix[p][n])
    >> retmatrix.__matrix[m][n] = product
    >>
    >> Here is what i have so far:
    >> retmatrix.__matrix = [[ product = product + (self.__matrix[m][p]*
    >> other.__matrix[p][n])
    >> if product else self.__matrix[m][p]* other.__matrix[p][n])
    >> for p in range(0,self.col)
    >> for n in range(0,self.col)]
    >> for m in range(0,self.__row)]
    >>
    >> But i know that isn't correct, can someone nudge my in the right direction?
    >>
    >>

    >
    > The biggest thing to learn about list comprehensions is when not to use
    > them. I can't imagine how your latter version (even if correct) is
    > clearer than the first.


    I think he might be using the wrong function for a matrix
    multiplication, not that it's not workable, but there are other
    libraries like numpy that could help out.

    I wouldn't use list comprehension for this, unless it might be several
    lists that interact.
    >
    >
    >
    > --
    >
    > DaveA
    >
    > --
    > http://mail.python.org/mailman/listinfo/python-list




    --
    Best Regards,
    David Hutto
    CEO: http://www.hitwebdevelopment.com
     
    Dwight Hutto, Oct 17, 2012
    #1
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Mark Elston

    List Comprehension question

    Mark Elston, Dec 11, 2003, in forum: Python
    Replies:
    1
    Views:
    324
    Francis Avila
    Dec 11, 2003
  2. Eelco Hoekema

    [Newby question] List comprehension

    Eelco Hoekema, Aug 6, 2004, in forum: Python
    Replies:
    7
    Views:
    293
    Eelco Hoekema
    Aug 6, 2004
  3. Shane Geiger
    Replies:
    4
    Views:
    396
    bullockbefriending bard
    Mar 25, 2007
  4. Debajit Adhikary
    Replies:
    17
    Views:
    699
    Debajit Adhikary
    Oct 18, 2007
  5. Vedran Furac(
    Replies:
    4
    Views:
    339
    Marc 'BlackJack' Rintsch
    Dec 19, 2008
Loading...

Share This Page