Hi Georg,
Georg Ehret wrote:
> Dear R,
> I am writing a simple function to extract the sign of values and apply it
> to a data frame (see below). Whatever I do I get error-messages... What is
> wrong?
The main problem here is you are ignoring existing functions that will
do the job much better. See ?sign.
And the error you see is because you are doing a single comparison, but
passing a vector for x (e.g., x<0 tests if one thing is less than zero,
but you pass a vector, so you get x[1]<0).
Best,
Jim
>
> Thanking you in advance,
> Cheers, Georg.
> ***********************
> Georg Ehret
> Institute of Genetic Medicine
> Johns Hopkins University
> Baltimore
>
>
>> extractsign<-function(x){
> + if (x<0) a<--1
> + else a<-1
> + return (a)
> + }
>> a
> meanSBP meanSBP_tttcorr res_asb_SBP res_asb_SBP_tttcorr meanDBP
> meanDBP_tttcorr res_asb_DBP res_asb_DBP_tttcorr
> one -0.04 -0.01 -0.11 -0.05
> 0.18
> 0.24 0.18 0.24
> two 0.06 0.01 0.33 0.24
> 0.00
> -0.02 0.05 0.03
> three -0.01 0.01 -0.07 -0.01
> -0.01
> 0.00 -0.05 -0.01
> four -0.14 -0.05 -0.05 0.00
> -0.85
> -0.59 -0.79 -0.55
> five 0.12 0.06 0.17 0.07
> 0.34
> 0.21 0.60 0.44
> six -0.06 -0.01 -0.05 -0.01
> -0.26
> -0.14 -0.41 -0.25
>> lapply(a,extractsign)
> $meanSBP
> [1] -1
>
> $meanSBP_tttcorr
> [1] -1
>
> $res_asb_SBP
> [1] -1
>
> $res_asb_SBP_tttcorr
> [1] -1
>
> $meanDBP
> [1] 1
>
> $meanDBP_tttcorr
> [1] 1
>
> $res_asb_DBP
> [1] 1
>
> $res_asb_DBP_tttcorr
> [1] 1
>
> Warning messages:
> 1: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 2: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 3: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 4: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 5: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 6: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 7: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
> 8: In if (x < 0) a <- -1 else a <- 1 :
> the condition has length > 1 and only the first element will be used
>
> [[alternative HTML version deleted]]
>
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--
James W. MacDonald, M.S.
Biostatistician
Affymetrix and cDNA Microarray Core
University of Michigan Cancer Center
1500 E. Medical Center Drive
7410 CCGC
Ann Arbor MI 48109
734-647-5623
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