[R] If statement not working in a for loop when making it independent

[Jeff Newmiller]

You have really tied yourself up in a knot here. Last I checked, when A==B, then B==A. You also need to study the difference between ?if and ?ifelse, since you are not giving the if function the scalar it expects. For example, i$ID is a vector of three (identical, due to your use of split) values, so %in% will return three logical values.
I think one way to do this is to replace

i$ID %in% data_qual[data_qual$ID %in% i$ID,]$ID

with

i[ 1, "ID" ] %in% data_qual[ , "ID"]

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Sent from my phone. Please excuse my brevity.

On September 29, 2014 4:05:54 PM PDT, Nebulo Archae <nebuloso78 at gmx.ch> wrote:
>Dear all,
>
>I have a data.frame xy that contains numeric data and data_qual which
>contains qualitative data which I want to include in a for loop with an
>if statement (commented out in the code below).
>The if statement should be applied if the ID in data_qual$ID is the
>same than in xy$ID.
>
>I am trying to make it independent by doing this:
>
>if(i$ID %in% data_qual[data_qual$ID %in% i$ID,]$ID){...}
> 
>but it doesn't work when I incorporate it in the for loop. The logical
>result is correct but it only works for the first element when
>implemented in the for loop. Can anyone see what I am doing wrong here?
>
>#######################
>Here is my code:
>xy
><-data.frame(NAME=c("NAME1","NAME1","NAME1","NAME2","NAME2","NAME2","NAME3","NAME3"),ID=c(87,87,87,199,199,199,233,233),X_START_YEAR=c(1950,1988,1994,1899,1909,1924,1945,1948),Y_START_VALUE=c(75,25,-90,-8,-55,-10,-9,12),X_END_YEAR=c(1985,1994,1999,1904,1924,1987,1946,1949),
>Y_END_VALUE=c(20,50,-15,-70,-80,-100,24,59))
> 
>data_qual <-
>data.frame(NAME=c("NAME2","NAME3"),ID=c(199,233),X_START_YEAR=c(1986,1905),
>Y_START_VALUE=c("-X","ST"),X_END_YEAR=c(1987,1907),Y_END_VALUE=c("-X","ST"))
> 
># split xy by group as defined by ID
>ind <- split(xy,xy$ID)
> 
>for (i in ind){xx = unlist(i[,grep('X_',colnames(i))]) 
>               yy = unlist(i[,grep('Y_',colnames(i))]) 
>               fname <- paste0(i[1, 'ID'], '.png') 
>               png(fname, width=1679, height=1165, res=150)
>  if(any(xx < 1946)) {my_x_lim <- c(min(xx), 2014)} else {my_x_lim <-
>c(1946, 2014)} 
>  par(mar=c(6,8,6,5))
>  plot(xx, yy,main=unique(i[,1]),xlab="Time [Years]",ylab="Value
>[m]",pch=21,xlim = my_x_lim,font.lab=2, cex.lab=1.2, cex.axis=1.1)
>  i <- i[,-1]
>  segments(i[,2],i[,3],i[,4],i[,5],lwd=2)
> 
> # if(i$ID %in% data_qual[data_qual$ID %in% i$ID,]$ID){
> #     rel_data_qual <- data_qual[data_qual$ID %in% i$ID,]
> #     text(x = rel_data_qual$X_END_YEAR,
> #          y = min(i$Y_END_VALUE + 3),
> #     labels = rel_data_qual$Y_END_VALUE)  
> #   }
> 
>  dev.off()
>}
>
>Thanks, Kurt
>
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