Dear list,
I am trying to evaluate how many elements in a vector equal a certain value.
The vectors are the columns of a data.frame, read in using read.table():
> dim(data)
[1] 2600 742
> data[1:5,1:5]
SNP001 SNP002 SNP003 SNP004 SNP005
1 GG AA TT TT GG
2 GG AA TC TT GG
3 GG AC CC TT GG
4 AG AA TT TT GG
5 GG AA TC TT GG
> table(data[,1])
AA AG GG
251 1093 1252
but if I do
> sum(data[,1]=="GG")
[1] NA
I have tried storing the column it in a vector but with same results:
> yyy<-(data[,1])
> sum(yyy=="GG")
[1] NA
while if I just get a small number of elements from this vector, it works fine
> yyyy <- yyy[1:10]
> yyyy
[1] "GG" "GG" "GG" "AG" "GG" "GG" "AA" "GG" "AG" "GG"
> table(yyyy)
yyyy
AA AG GG
1 2 7
> sum(yyyy=="GG")
[1] 7
I checked the archives for help but couldn“t find my error
What am I missing?
> sessionInfo()
R version 2.8.1 (2008-12-22)
i386-pc-mingw32
attached base packages:
[1] stats graphics grDevices utils datasets methods base
Thanks
Dave
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