[R] Averaging across rows columns
I use Windows, R version 2.4.1. I have a dataset in which columns 1-3 are replicates, 4-6, are replicates, etc. I need to calculate an average for every set of replicates (columns 1-3, 4-6, 7-9, etc.) AND each set of replicates should be averaged every 14 rows (for more detail, to measure fruit color using a spectrometer, I recorded three readings per fruit -replicates- that I need to average to get one reading per fruit; each row is a point in the light spectrum and I need to calculate an average reading every 5nm -14 rows- for each fruit). Someone proposed to another user who wanted an avg across columns to do a - matrix(rnorm(360),nr=10) b - rep(1:12,each=3) avgmat - aggregate(a,by=list(b)) I tried doing this to get started with the columns first but it asks for an argument FUN that has no default. The help for aggregate isn't helping me much (a new R user) to discover what value to give to FUN -'average' doesn't seem to exist, and 'sum' (whatever it is supposed to sum) gives an error saying that arguments should have the same length- Any help will be much appreciated! Silvia. -- View this message in context: http://www.nabble.com/Averaging-across-rows---columns-tf3885900.html#a11014649 Sent from the R help mailing list archive at Nabble.com. __ R-help@stat.math.ethz.ch 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.
Re: [R] Averaging across rows columns
Check out rowMeans to average over replicate columns first, ie: means - data.frame(t1=rowMeans(a[,1:3]), t2=rowMeans(a[,4:6]), etc) Then, if you want to aggregate every 14 rows: aggregate(means, by=list(rows=rep(1:(nrow(means)/14), each=14)), mean) Or something... -Original Message- From: [EMAIL PROTECTED] on behalf of Silvia Lomascolo Sent: Thu 07/06/2007 8:26 PM To: r-help@stat.math.ethz.ch Subject: [R] Averaging across rows columns I use Windows, R version 2.4.1. I have a dataset in which columns 1-3 are replicates, 4-6, are replicates, etc. I need to calculate an average for every set of replicates (columns 1-3, 4-6, 7-9, etc.) AND each set of replicates should be averaged every 14 rows (for more detail, to measure fruit color using a spectrometer, I recorded three readings per fruit -replicates- that I need to average to get one reading per fruit; each row is a point in the light spectrum and I need to calculate an average reading every 5nm -14 rows- for each fruit). Someone proposed to another user who wanted an avg across columns to do a - matrix(rnorm(360),nr=10) b - rep(1:12,each=3) avgmat - aggregate(a,by=list(b)) I tried doing this to get started with the columns first but it asks for an argument FUN that has no default. The help for aggregate isn't helping me much (a new R user) to discover what value to give to FUN -'average' doesn't seem to exist, and 'sum' (whatever it is supposed to sum) gives an error saying that arguments should have the same length- Any help will be much appreciated! Silvia. -- View this message in context: http://www.nabble.com/Averaging-across-rows---columns-tf3885900.html#a11014649 Sent from the R help mailing list archive at Nabble.com. __ R-help@stat.math.ethz.ch 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. __ R-help@stat.math.ethz.ch 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.
Re: [R] Averaging across rows columns
michael watson (IAH-C) wrote: Check out rowMeans to average over replicate columns first, ie: means - data.frame(t1=rowMeans(a[,1:3]), t2=rowMeans(a[,4:6]), etc) Then, if you want to aggregate every 14 rows: aggregate(means, by=list(rows=rep(1:(nrow(means)/14), each=14)), mean) Or something... YES! This seems to work. Thank you! -Original Message- From: [EMAIL PROTECTED] on behalf of Silvia Lomascolo Sent: Thu 07/06/2007 8:26 PM To: r-help@stat.math.ethz.ch Subject: [R] Averaging across rows columns I use Windows, R version 2.4.1. I have a dataset in which columns 1-3 are replicates, 4-6, are replicates, etc. I need to calculate an average for every set of replicates (columns 1-3, 4-6, 7-9, etc.) AND each set of replicates should be averaged every 14 rows (for more detail, to measure fruit color using a spectrometer, I recorded three readings per fruit -replicates- that I need to average to get one reading per fruit; each row is a point in the light spectrum and I need to calculate an average reading every 5nm -14 rows- for each fruit). Someone proposed to another user who wanted an avg across columns to do a - matrix(rnorm(360),nr=10) b - rep(1:12,each=3) avgmat - aggregate(a,by=list(b)) I tried doing this to get started with the columns first but it asks for an argument FUN that has no default. The help for aggregate isn't helping me much (a new R user) to discover what value to give to FUN -'average' doesn't seem to exist, and 'sum' (whatever it is supposed to sum) gives an error saying that arguments should have the same length- Any help will be much appreciated! Silvia. -- View this message in context: http://www.nabble.com/Averaging-across-rows---columns-tf3885900.html#a11014649 Sent from the R help mailing list archive at Nabble.com. __ R-help@stat.math.ethz.ch 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. __ R-help@stat.math.ethz.ch 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. -- View this message in context: http://www.nabble.com/Averaging-across-rows---columns-tf3885900.html#a11015925 Sent from the R help mailing list archive at Nabble.com. __ R-help@stat.math.ethz.ch 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.
