如何进行循环

Question

I'd like to make for loop functions below contents.

p1 <- read.table("positive1.txt")
 (wordcount=table(p1))
 palete=brewer.pal(9,"Set1")
 wordcloud(names(wordcount), freq=wordcount, scale=c(5,1),
 rot.per=.12,min.freq=1, random.order=F, random.color=T, colors=palete)

p2 <- read.table("positive2.txt")
 (wordcount=table(p2))
 palete=brewer.pal(9,"Set1")
 wordcloud(names(wordcount), freq=wordcount, scale=c(5,1),
      rot.per=.12,min.freq=1, random.order=F, random.color=T, colors=palete)

p3 <- read.table("positive3.txt")
(wordcount=table(p3))
palete=brewer.pal(9,"Set1")
wordcloud(names(wordcount), freq=wordcount, scale=c(5,1),
      rot.per=.12,min.freq=1, random.order=F, random.color=T, colors=palete)

When I write below sentences, I received error messages.

par(mfrow(1,3))
for (i in 1:3) {
p[i] <- readLines(con="positive[i].txt")
p0[i] <- scan("positive[i].txt", character(0), sep = "\n") 
(wordcount[i]=table(p0[i]))
palete=brewer.pal(9,"Set1")
wordcloud(names(wordcount[i]), freq=wordcount, scale=c(5,1),
      rot.per=.12,min.freq=1, random.order=F, random.color=T, colors=palete)
} 

These are my error messages:

 Error in file(con, "r") : cannot open the connection In addition: Warning message: In file(con, "r") : cannot open file 'positive*.txt': Invalid argument 

Answer 1

Consider lapply to save p items into a list and keep using the read.table() approach:

txt_files <- paste0("positive", 1:3, ".txt")

p <- lapply(txt_files, function(f) {
   tmp <- read.table(f)
   (wordcount=table(tmp))
   palete=brewer.pal(9,"Set1")
   wordcloud(names(wordcount), freq=wordcount, scale=c(5,1),
      rot.per=.12, min.freq=1, random.order=F, random.color=T, colors=palete)
})

Answer 2

This string: "positive[i].txt" isn't going to be interpreted the way you want it to be.

Try paste0("positive", i, ".txt") instead.