[R] Odp: counting columns that fulfill specific criteria

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 24.06.2011 16:51:27:

> 
> Thanks for your reply, but that is not quite what I am looking for...I 
do not
> want to add up all the values in the row, I want to get the number of
> columns in each row that meet the criteria and then get that as a
> percentage....
> 
> my understanding is that the rowSums function adds up the values does it
> not? I tried your code anyways and it did not work:
> 
> Error in abs(pwdiff) >= t : 
>   comparison (5) is possible only for atomic and list types

That is why some ***reproducible code*** shall be provided from your side

rowSums(USArrests>50)/ncol(USArrests)*100

gives no error and the result tells you percentage of columns for which in 
each row holds that the number is greater than 50. This may be what you 
want.

rowSums(USArrests>50)

simply tells you how many values in each row are greater than specified 
threshold and dividing it by total number of columns gives you percentage.

The error you got means that pwdiff is probably not data frame or t is 
probably not one number. Only you can know that.

For evaluating your objects you can try

str(pwdiff)
str(t)

Besides t is a function or transposing data so you shall find some 
different name for your constant.

Regards
Petr
 

> 
> and when specifying the columns
> (perc[x]<-rowSums(pwdiff[,abs(pwdiff[x,])>=thr], na.rm=T)/ncol(pwdiff)), 
I
> get the following error:
> 
> Error in rowSums(pwdiff[, abs(pwdiff[x, ]) >= thr], na.rm = T) : 
>   'x' must be an array of at least two dimensions
> In addition: There were 30 warnings (use warnings() to see them)
> > warnings()
> Warning messages:
> 1: In perc[x] <- rowSums(pwdiff[, abs(pwdiff[x, ]) >= thr],  ... :
>   number of items to replace is not a multiple of replacement length
> ...
> 
> 
> Ive been trying to sort this out for the past three days and cannot get 
it
> to work for some reason...I can do it SO easily in excel with a simple
> macro, but doing that on a 480000x780 table inevitably crashes the
> computer...
> 
> Any more help you can provide would be great, thanks!
> 
> 
> 
> 
> --
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> columns-that-fulfill-specific-criteria-tp3622265p3622711.html
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