Fwd: numpy/matlab compatibility

Discussion in 'Python' started by Andrea Ambu, Jan 25, 2011.

  1. Andrea Ambu

    Andrea Ambu Guest

    I replied to Matt only ARGH!


    ---------- Forwarded message ----------
    From: Andrea Ambu <>
    Date: 25 January 2011 22:36
    Subject: Re: numpy/matlab compatibility
    To: Matt Funk <>




    On Tue, Jan 25, 2011 at 9:13 PM, Matt Funk <> wrote:
    >
    > Hi,
    >
    > i am fairly new to python. I was wondering of the following is do-able
    > in python:
    >
    > 1) a = rand(10,1)
    > 2) Y = a
    > 3) mask = Y > 100;
    > 4) Y(mask) = 100;
    > 5) a = a+Y
    >


    No. Not like that.
    You do literally:
    a = rand(10, 1)
    Y = a
    mask = Y>100
    Y = where(mask, 100, Y)
    a = a+Y

    More Pythonically:
    a = rand(10, 1)
    a = where(a > 100, a + 100, a + a)

    For those who don't speak Matlab:
    1) a = rand(10,1) ; generates a 10x1 matrix for random number 0 < n < 1
    2) Y = a
    3) mask = Y > 100; similar to: mask = [i>100 for i in Y]
    4) Y(mask) = 100; sets to 100 elements of Y with index i for which
    mask = True
    5) a = a+Y ; sums the two matrices element by element (like you do in
    linear algebra)

    Anyway... rand generates number from 0 up to 1 (both in python and
    matlab)... when are they > 100?

    >
    > Basically i am getting stuck on line 4). I was wondering if it is
    > possible or not with python?
    > (The above is working matlab code)
    >
    > thanks
    > matt
    > --
    > http://mail.python.org/mailman/listinfo/python-list





    --
    Andrea
     
    Andrea Ambu, Jan 25, 2011
    #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. Davide Carboni
    Replies:
    0
    Views:
    384
    Davide Carboni
    Dec 18, 2003
  2. siki
    Replies:
    0
    Views:
    1,005
  3. Luna Moon
    Replies:
    16
    Views:
    1,434
    Giovanni Gherdovich
    Aug 8, 2008
  4. Matt Funk

    numpy/matlab compatibility

    Matt Funk, Jan 25, 2011, in forum: Python
    Replies:
    1
    Views:
    205
    Steven D'Aprano
    Jan 25, 2011
  5. someone
    Replies:
    39
    Views:
    1,495
    someone
    May 4, 2012
Loading...

Share This Page