Preserve uppercase in tagcloud

Question

I want to make a tag cloud to visualize the gene frequency.

library(wordcloud)

genes_snv <- read.csv("genes.txt", sep="", header=FALSE)

wordcloud(genes_snv$V1,
          min.freq=15,
          scale=c(5,0.5),
          max.words=100,
          random.order=FALSE,
          rot.per=0.3,
          colors=brewer.pal(8, "Dark2"))

This is my code, but it converts everything to lowercase (not useful with gene names). How can I avoid this?

genes.txt starts with

Fcrl5
Etv3
Etv3
Lrrc71
Lrrc71
(...)

Answer 1

When freq argument is missing wordcloud calls tm::TermDocumentMatrix, which I guess internally calls function tolower before computing frequency.

To avoid calls to tm we can supply our own frequency, see example:

# dummy data
set.seed(1)
genes <- c("Fcrl5","Etv3","Etv3","Lrrc71","Lrrc71")
genes <- unlist(sapply(genes, function(i)rep(i, sample(1:100,1))))

# get frequency
plotDat <- as.data.frame(table(genes))

# plot
wordcloud(word = plotDat$genes, freq = plotDat$Freq,
          min.freq=15,
          scale=c(5,0.5),
          max.words=100,
          random.order=FALSE,
          rot.per=0.3,
          colors=brewer.pal(8, "Dark2"))