Thank you Matthias! You are most helpful!
Thanks again! Arijit ________________________________ From: Matthias Boehm <mboe...@googlemail.com> Sent: Saturday, April 22, 2017 2:20:48 AM To: dev@systemml.incubator.apache.org Subject: Re: Randomly Selecting rows from a dataframe you can take for example a 1% sample of rows via a permutation matrix (specifically selection matrix) as follows I = (rand(rows=nrow(X), cols=1, min=0, max=1) <= 0.01); P = removeEmpty(target=diag(I), margin="rows"); Xsample = P %*% X; or via removeEmpty and selection vector I = (rand(rows=nrow(X), cols=1, min=0, max=1) <= 0.01); Xsample = removeEmpty(target=X, margin="rows", select=I); Both should be compiled internally to very similar plans. Regards, Matthias On Fri, Apr 21, 2017 at 1:42 PM, arijit chakraborty <ak...@hotmail.com> wrote: > Hi, > > > Suppose I've a dataframe of 10 variables (X1-X10) and have 1000 rows. Now > I want to randomly select rows so that I've a subset of the dataset. > > > Can anyone please help me to solve this problem? > > > I tried the following code: > > > randSample = sample(nrow(dataframe), 200); > > > This gives me a column matrix with position of the row randomly selected. > But I could not able to solve how from this matrix I can subset data from > original dataframe. > > > Thank you! > > > Arijit >
