Hello,
I have some dataset, which i read it from external file using the (data <-
read.csv("my file location")) and read as a dataframe
> is(data)
[1] "data.frame" "list" "oldClass"
"vector"
but i have also converted this into a matrix and tried to apply my code but
didnt work.
Anyways, suppose i have the following data.
data <- as.data.frame(matrix(rnorm(100), nrow = 10))
And let's put some missing values
data[sample(1:10, 3), sample(1:10, 3)] <- NA
I want to replace all NA's by row averages or column averages of my matrix.
I tried to use(with my original data matrix)
data[is.na(data)] <- rowMeans(data, na.rm = TRUE)
But got an error message of
Error in rowMeans(data, na.rm = TRUE) : 'x' must be numeric
Then I converted data<- as.matrix(data)
data<- as.numeric(data)
And applying my code
data[is.na(data)] <- rowMeans(data, na.rm = TRUE)
Error message
Error in rowMeans(data, na.rm = TRUE) :
'x' must be an array of at least two dimensions
Then again i tried to convert it into Arrays....but the errors continues....
I Also tried the code
data[is.na(data)] <- apply(data,1,mean)
But still didnt work out.
Can anyone pls help me as to how to fix it and get out of this, please?
Thank you very much
Daniel
[[alternative HTML version deleted]]
Hi Daniel, If your data is stored in a matrix, the following should work (and be fairly efficient): ############# dat <- matrix(rnorm(100), nrow = 10) dat[sample(1:10, 3), sample(1:10, 3)] <- NA ## create an index of missing values index <- which(is.na(dat), arr.ind = TRUE) ## calculate the row means and "duplicate" them to assign to appropriate cells dat[index] <- rowMeans(dat, na.rm = TRUE)[index[, "row"]] ## for documentation see ?which # particularly the arr.ind argument ?"[" # for extraction or selecting a subset to overwrite ############# the only reason this does not work as is with data frames is because of how they are indexed/subset. dat[index] does not work. The required modification is probably fairly minimal, but if you are happy to use a matrix, then its a moot issue. HTH, Josh On Sun, Feb 27, 2011 at 3:25 PM, Daniel M. <danielmessay at yahoo.com> wrote:> Hello, > > I have some dataset, which i read it from external file using the (data <- > read.csv("my file location")) and read as a dataframe > >> is(data) > [1] "data.frame" "list" ? ? ? "oldClass" ? "vector" > but i have also converted this into a matrix and tried to apply my code but > didnt work. > > Anyways, suppose i have the following data. > > > ? ?data <- as.data.frame(matrix(rnorm(100), nrow = 10)) > > And let's put some missing values > > ? ?data[sample(1:10, 3), sample(1:10, 3)] <- NA > > I want to replace all NA's by row averages or column averages of my matrix. > > I tried to use(with my original data matrix) > > ? ?data[is.na(data)] <- rowMeans(data, na.rm = TRUE) > But got an error message of > > ? ? ? Error in rowMeans(data, na.rm = TRUE) : 'x' must be numeric > Then I converted ?data<- as.matrix(data) > ? ? ? ? ? ? ? ? ?data<- as.numeric(data) > And applying my code > > ? ? data[is.na(data)] <- rowMeans(data, na.rm = TRUE) > > Error message > > > ? ? ?Error in rowMeans(data, na.rm = TRUE) : > ?'x' must be an array of at least two dimensions > > Then again i tried to convert it into Arrays....but the errors continues.... > > I Also tried the code > > ? ?data[is.na(data)] <- apply(data,1,mean) > > But still didnt work out. > > Can anyone pls help me as to how to fix it and get out of this, please? > > Thank you very much > > Daniel > > > > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > 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. >-- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.com/
Warning: This is not a helpful answer. Actually, it's a question: Why do you want to do this? Replacing missing values with row or column averages and then analyzing the data as if the missing values were not there is a dangerous thing to do it can produce biased estimates and understate the true error, likely resulting in biased inference. Of course, this depends on the specifics (how many are missing and where). R has a lot of built-in capabilities for handling missing values. I agree: it's not easy stuff. Nor do you necessarily need to get that complicated: Maybe your scheme is perfectly adequate for your situation. I just wanted to caution you think about this carefully if you aren't aware of the possible problems and haven't already done so. -- Bert On Sun, Feb 27, 2011 at 3:25 PM, Daniel M. <danielmessay at yahoo.com> wrote:> Hello, > > I have some dataset, which i read it from external file using the (data <- > read.csv("my file location")) and read as a dataframe > >> is(data) > [1] "data.frame" "list" ? ? ? "oldClass" ? "vector" > but i have also converted this into a matrix and tried to apply my code but > didnt work. > > Anyways, suppose i have the following data. > > > ? ?data <- as.data.frame(matrix(rnorm(100), nrow = 10)) > > And let's put some missing values > > ? ?data[sample(1:10, 3), sample(1:10, 3)] <- NA > > I want to replace all NA's by row averages or column averages of my matrix. > > I tried to use(with my original data matrix) > > ? ?data[is.na(data)] <- rowMeans(data, na.rm = TRUE) > But got an error message of > > ? ? ? Error in rowMeans(data, na.rm = TRUE) : 'x' must be numeric > Then I converted ?data<- as.matrix(data) > ? ? ? ? ? ? ? ? ?data<- as.numeric(data) > And applying my code > > ? ? data[is.na(data)] <- rowMeans(data, na.rm = TRUE) > > Error message > > > ? ? ?Error in rowMeans(data, na.rm = TRUE) : > ?'x' must be an array of at least two dimensions > > Then again i tried to convert it into Arrays....but the errors continues.... > > I Also tried the code > > ? ?data[is.na(data)] <- apply(data,1,mean) > > But still didnt work out. > > Can anyone pls help me as to how to fix it and get out of this, please? > > Thank you very much > > Daniel > > > > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > 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. >-- Bert Gunter Genentech Nonclinical Biostatistics