[R] Remove columns from dataframe based on their statistics

2012-05-31 Thread Johannes Radinger
Hi, I have a dataframe and want to remove columns from it that are populated with a similar value (for the total column) (the variation of that column is 0). Is there an easier way than to calculate the statistics and then remove them by hand? A - runif(100) B - rep(1,100) C - rep(2.42,100) D -

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread J Toll
On Thu, May 31, 2012 at 8:27 AM, Johannes Radinger jradin...@gmx.at wrote: Hi, I have a dataframe and want to remove columns from it that are populated with a similar value (for the total column) (the variation of that column is 0). Is there an easier way than to calculate the statistics and

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread Jorge I Velez
Hi Johannes, Try df[, !apply(df, 2, function(x) sd(x, na.rm = TRUE) 1e-10)] HTH, Jorge.- On Thu, May 31, 2012 at 9:27 AM, Johannes Radinger wrote: Hi, I have a dataframe and want to remove columns from it that are populated with a similar value (for the total column) (the variation of

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread J Toll
On Thu, May 31, 2012 at 8:52 AM, J Toll jct...@gmail.com wrote: for (i in seq(ncol(df), 1))  if (length(unique(df[, i])) == 1) {  df[, i] - NULL } Here's a similar method employing a more functional approach: df[, apply(df, 2, function(x) length(unique(x)) 1)] James

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread Johannes Radinger
with name B. I have to think about this /Johannes Original-Nachricht Datum: Thu, 31 May 2012 09:20:27 -0500 Von: J Toll jct...@gmail.com An: Johannes Radinger jradin...@gmx.at CC: R-help@r-project.org Betreff: Re: [R] Remove columns from dataframe based on their statistics

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread Jorge I Velez
, 31 May 2012 09:20:27 -0500 Von: J Toll jct...@gmail.com An: Johannes Radinger jradin...@gmx.at CC: R-help@r-project.org Betreff: Re: [R] Remove columns from dataframe based on their statistics On Thu, May 31, 2012 at 8:52 AM, J Toll jct...@gmail.com wrote: for (i in seq(ncol(df), 1

Re: [R] Remove columns from dataframe based on their statistics

2012-05-31 Thread arun
:52 AM Subject: Re: [R] Remove columns from dataframe based on their statistics On Thu, May 31, 2012 at 8:27 AM, Johannes Radinger jradin...@gmx.at wrote: Hi, I have a dataframe and want to remove columns from it that are populated with a similar value (for the total column) (the variation