with GGplot2 is there a way to select only 1 chart from a graph with multiple correlation charts

Question

Lets say i have the following graph: enter image description here

And i only want to select the 2nd graph of the first row. How can i do this with ggplot function as below:

plotAll<-function(data,size=2, alpha=0.4){
  combs <- expand.grid(names(data), names(data))
  out <- do.call(rbind, apply(combs, 1, function(x) {
    tt <- data[, x]; names(tt) <- c("V1", "V2")
    tt <- cbind(tt, id1 = x[1], id2 = x[2])
  }))

  library(plyr)
  df.text=ddply(out[out$id1==out$id2,],.(id1,id2),summarise,
                pos=max(V1)-(max(V1)-min(V1))/2)
  out[out$id1==out$id2,c("V1","V2")]<-NA
  out$labels <- rownames(out)
  out$labels<-sapply(out$labels, function(x){
    strsplit(x, "_")[[1]][1]
  })

  fam<-read.table('input/genomic_info_subset.tsv', sep='\t')

  idx<-match(out$labels,fam$V1)
  newcol<-fam$V4[idx]
  newcol<-as.character(newcol)
  out$fam<-newcol

  ggplot(data = out, aes(x = V2, y = V1)) +
    geom_text(data = out[!is.na(out$V1),], aes(label = labels, colour=fam), size=size, alpha=alpha) +
    facet_grid(id1 ~ id2,scales="fixed")+
    geom_text(data=df.text,aes(pos,pos,label=id1)) + geom_abline( slope=1 ) + 
    ggtitle("Corralation between measured & calculated affinities") +
    ylab("") + xlab("") + theme(panel.grid.minor.x=element_blank(), panel.grid.major.x=element_blank())
}

So can i say somewhere in the code, select only the 2nd of 1st row? or is it more easy to just extract the data frame out of the function and than plot 1 separate? I know that this function is inappropriate for reproducing my question, if this really is neccecary i will provide the .tsv and dput the data.

Paul Hiemstra Paul Hiemstra · Accepted Answer · 2013-05-14T08:47:34

By far the easiest solution is to simply subset the data to only that which is relevant to the second column of the first row. Extracting plots from these kinds of facet plots is probably possible, but not trivial.

with GGplot2 is there a way to select only 1 chart from a graph with multiple correlation charts

1 Answers