[R] compare strings
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Sat Dec 1 09:55:58 CET 2007
Bernd Jagla wrote:
> It helps writing down these question, you are then getting much closer to an
> answer...
>
> summary(as.integer(t3[,2]) == as.integer(t3[,4]) & as.integer(t3[,3]) ==
> as.integer(t3[,5]))
>
> will compare two pairs of column pairs and give a count of flase and true
> rows...
>
>
If they really are factors with different level sets, I think you might
prefer as.character() there.
> x <- factor(c("a","b"))
> y <- factor(c("b","c"))
> x==y
Error in Ops.factor(x, y) : level sets of factors are different
> as.integer(x)==as.integer(y)
[1] TRUE TRUE
> as.character(x)==as.character(y)
[1] FALSE FALSE
Also, extending the above slightly:
> d <- as.character(x)==as.character(y)
> table(d)
d
FALSE TRUE
2 1
> which(!d)
[1] 1 2
> -B
>
> |-----Original Message-----
> |From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> |Behalf Of Bernd Jagla
> |Sent: Friday, November 30, 2007 10:25 PM
> |To: r-help at r-project.org
> |Subject: [R] compare strings
> |
> |Sorry for the question, but I really cannot find the right search terms to
> |find an answer..
> |
> |
> |
> |I have a data frame with strings in some of the columns.
> |
> |I want to know all the rows where the strings in both columns are equal.
> |
> |
> |
> |How do I do this?
> |
> |
> |
> |Thanks,
> |
> |
> |
> |Bernd
> |
> |
> | [[alternative HTML version deleted]]
> |
> |______________________________________________
> |R-help at r-project.org mailing list
> |https://stat.ethz.ch/mailman/listinfo/r-help
> |PLEASE do read the posting guide http://www.R-project.org/posting-
> |guide.html
> |and provide commented, minimal, self-contained, reproducible code.
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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