# Hello,
# I have a matrix that contains some missing values denoted by NA.
# I would like to calculate the mean for each column and not have the
# NA values included. here is a sample matrix "X" below.
c1 <- c(1,4,3,2,NA,2,5,6,4,2)
c2 <- c(1,3,6,NA,NA,2,9,6,1,2)
c3 <- c(2,4,2,NA,4,2,NA,6,3,5)
c4 <- c(2,6,4,NA,4,2,NA,6,1,5)
c5 <- c(2,3,2,NA,4,2,9,6,NA,5)
X<-cbind(c1,c2,c3,c4,c5)
X
# I have tried a variety of methods to calculate the Column means but each time
# i do not get the result i am looking for
result<-colMeans(X) # only returns a mean of NA
X <- X[!is.na(X)] # Effectively removes the NA values but now I
cannot calculate Column Means
# Below is the result of the column means I am looking for
result
c1 c2 c3 c4 c5
[1,] 3.22 3.75 3.5 3.75 4.125
# any help or ideas would be greatly appreciated
# thanks in advance
Luke Neraas
lukasneraas.r at gmail.com
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
11120 Glacier Highway
UAF Fisheries Division
Juneau, AK 99801
colMeans(X,na.rm=T) ?colMeans 2007/11/27, Luke Neraas <lukasneraas.r at gmail.com>:> # Hello, > > # I have a matrix that contains some missing values denoted by NA. > # I would like to calculate the mean for each column and not have the > # NA values included. here is a sample matrix "X" below. > > > c1 <- c(1,4,3,2,NA,2,5,6,4,2) > c2 <- c(1,3,6,NA,NA,2,9,6,1,2) > c3 <- c(2,4,2,NA,4,2,NA,6,3,5) > c4 <- c(2,6,4,NA,4,2,NA,6,1,5) > c5 <- c(2,3,2,NA,4,2,9,6,NA,5) > > X<-cbind(c1,c2,c3,c4,c5) > > X > > # I have tried a variety of methods to calculate the Column means but each time > # i do not get the result i am looking for > > result<-colMeans(X) # only returns a mean of NA > > > X <- X[!is.na(X)] # Effectively removes the NA values but now I > cannot calculate Column Means > > # Below is the result of the column means I am looking for > > result > c1 c2 c3 c4 c5 > [1,] 3.22 3.75 3.5 3.75 4.125 > > > # any help or ideas would be greatly appreciated > > # thanks in advance > > Luke Neraas > > lukasneraas.r at gmail.com > > University of Alaska Fairbanks > School of Fisheries and Ocean Sciences > 11120 Glacier Highway > UAF Fisheries Division > Juneau, AK 99801 > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
Peter Alspach
2007-Nov-27 01:27 UTC
[R] calculate column means when missing data is present
Luke Check ?colMeans or help(colMeans) you will see there is an agrument, na.rm, which by default is FALSE - you need to set it to TRUE. Peter Alspach> -----Original Message----- > From: r-help-bounces at r-project.org > [mailto:r-help-bounces at r-project.org] On Behalf Of Luke Neraas > Sent: Tuesday, 27 November 2007 1:59 p.m. > To: r-help > Subject: [R] calculate column means when missing data is present > > # Hello, > > # I have a matrix that contains some missing values denoted by NA. > # I would like to calculate the mean for each column and not > have the # NA values included. here is a sample matrix "X" below. > > > c1 <- c(1,4,3,2,NA,2,5,6,4,2) > c2 <- c(1,3,6,NA,NA,2,9,6,1,2) > c3 <- c(2,4,2,NA,4,2,NA,6,3,5) > c4 <- c(2,6,4,NA,4,2,NA,6,1,5) > c5 <- c(2,3,2,NA,4,2,9,6,NA,5) > > X<-cbind(c1,c2,c3,c4,c5) > > X > > # I have tried a variety of methods to calculate the Column > means but each time # i do not get the result i am looking for > > result<-colMeans(X) # only returns a mean of NA > > > X <- X[!is.na(X)] # Effectively removes the NA values but now I > cannot calculate Column Means > > # Below is the result of the column means I am looking for > > result > c1 c2 c3 c4 c5 > [1,] 3.22 3.75 3.5 3.75 4.125 > > > # any help or ideas would be greatly appreciated > > # thanks in advance > > Luke Neraas > > lukasneraas.r at gmail.com > > University of Alaska Fairbanks > School of Fisheries and Ocean Sciences > 11120 Glacier Highway > UAF Fisheries Division > Juneau, AK 99801 > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >The contents of this e-mail are privileged and/or confidential to the named recipient and are not to be used by any other person and/or organisation. If you have received this e-mail in error, please notify the sender and delete all material pertaining to this e-mail.