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I want to sample within groups, and when a group has only one associated number to just return that number. If I use this code: groups <- c(1, 2, 2, 2, 3) numbers <- 1:5 tapply(numbers, groups, FUN = sample) I get the following output: > groups <- c(1, 2, 2, 2, 3) > numbers <- 1:5 > tapply(numbers, groups, FUN = sample) $`1` [1] 1 $`2` [1] 3 2 4 $`3` [1] 2 3 5 1 4

We are doing a power analysis by generating noisy data sets according to a model, fitting the model to the data, and extracting a p-value. What is the best way to do this many times? We are just using for loops and it is too slow because we are repeating the analysis for many parameterizations. I can think of several ways to do this: for loop sapply using the plyr package using the lme4 package

* What were your biggest misconceptions or stumbling blocks to getting up and running with R? * What documents helped you the most in this initial phase? I especially want to hear from people who are lazy and impatient. Feel free to write to me off-list. Definitely write off-list if you are just confirming what has been said on-list. -- Patrick Burns pburns at pburns.seanet.com

...- An embedded and charset-unspecified text was scrubbed... Name: NAMESPACE URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20090527/6cb0ce2f/attachment-0001.pl> ------------------------------ Message: 77 Date: Wed, 27 May 2009 13:41:54 -0400 (EDT) From: "Jack Siegrist" <jacksie@eden.rutgers.edu> Subject: [R] contour lines on persp plot To: r-help@r-project.org Message-ID:     <3cf9f70cc9df289f6cfdb868581fd38d.squirrel@webmail.eden.rutgers.edu> Content-Type: text/plain;charset=iso-8859-1 Hello folks, I am a beginner R user. I have been able to make a 3D surface...

Hello folks, I am a beginner R user. I have been able to make a 3D surface plot using 'persp'. The surface is made by a grid of lines emanating perpendicularly from each of the x and y axes at regular intervals. I can get rid of that grid by setting 'border=NA'. Can anyone suggest some ways to replace the grid with contour lines, to create a 3-dimensional contour map? Thanks

Hello folks, Is there a way to invert the z axis in a 'persp' plot? I tried using 'zlim=rev(range(z))', which would work with 'plot' but does not work in this case. Thank you for your help.

I have a data set of many rows and many columns in which both the rows and the columns have associated grouping factors. Is there a way to do what 'aggregate' does but in the other dimension? The way I have been doing this is to use 'aggregate' on the data in the usual way and then rotate the result and apply 'aggregate' again. This works but is a little messy and I was

Hello, The function barplot automatically creates a y-axis that doesn't necessarily cover the range of y-values to be plotted. I know how to manually create my own y-axis so that it does cover the range, but I was wondering if there is some parameter to change so that the scale of the y-axis is automatically taller than the tallest bar. I thought setting xpd=F would do it, since it says that