You need to read up on indexing in R. What you want is logical indexing. You
can use just the vectors you created (since you didn't save the data frame that
you created) like this
> cycle=c(rep(1,3),rep(2,3),rep(3,3),rep(4,3))
> col=c(rep("blue",2),rep("green",2),rep("blue",2),rep("green",2),rep("blue",2),rep("green",2))
> values=c(1:12)
> values[col==blue & cycle==1]
Or save the data frame and return the rows that you want like this
> df <- data.frame(cycle,col,values)
> df[df$col==blue & df$cycle==1, ]
Hope this is helpful,
Dan
Daniel Nordlund, PhD
Research and Data Analysis Division
Services & Enterprise Support Administration
Washington State Department of Social and Health Services
-----Original Message-----
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Rodrigo Díaz
Sent: Tuesday, August 04, 2015 1:50 PM
To: r-help@r-project.org
Subject: [R] Two conditions selection
Hi. I have a matrix like this:
cycle=c(rep(1,3),rep(2,3),rep(3,3),rep(4,3))col=c(rep("blue",2),rep("green",2),rep("blue",2),rep("green",2),rep("blue",2),rep("green",2))values=c(1:12)data.frame(cycle,col,values)
# cycle col values#1 1 blue 1#2 1 blue 2#3 1
green 3#4 2 green 4#5 2 blue 5#6 2 blue
6#7 3 green 7#8 3 green 8#9 3 blue 9#10 4
blue 10#11 4 green 11#12 4 green 12
I want to select or extract values matching 2 conditions. For example: values
from col "blue" and cycle "1". If I use : values[col==blue] I get all blue
values. I tried using values[c(col==blue,cycle==1)] but is not working. Please
help. I have a very big data matrix and I do not wanna go to excel and start
cutting the data. Thanks.
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