[R] Howto sort dataframe columns by colMeans

[Liaw, Andy]

Something like the following may do what you want:

R> mydata.sorted <- mydata[c(1, 1 + order(colMeans(mydata[-1]),
decreasing=TRUE))]
R> mydata.sorted
   time met.c met.a met.b
1 00:00    99    42    18
2 00:05    67    88    16
3 00:10    84    80    27

(Note that I'm assuming that your first variable in the data frame is
not one of the things you want to include in your sorting.)

Andy


From: Lynn Osburn
> 
> I read from external data source containing several columns.  
> Each column
> represents value of a metric.  The columns are time series data.
> 
> I want to sort the resulting dataframe such that the column 
> with the largest
> mean is the leftmost column, descending in colMean values to 
> the right.
> 
> I see many solutions for sorting rows based on some column 
> characteristic,
> but haven't found any discussion of sorting columns based on column
> characteristics.
> 
> viz.  input data looks like this
>   time   met-a    met-b    met-c
> 00:00    42         18          99
> 00:05    88         16          67
> 00:10    80         27          84
> 
> desired output:
>  time   met-c    met-a     met-b
> 00:00    99         42          18
> 00:05    67         88          16
> 00:10    84         80          27
> 
> Thanks,
> -Lynn
> 
> -- 
> View this message in context: 
> http://www.nabble.com/Howto-sort-dataframe-columns-by-colMeans
> -tf4380044.html#a12485729
> Sent from the R help mailing list archive at Nabble.com.
> 
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