R: Is there a way to subset a file while reading

Question

I have a huge .csv file, its size is ~ 1.4G and reading with read.csv takes time. There are several variables in that file and all i want is to ext

Answer 1

I would say that most of the time you can probably just read in the entire file, and then subset within R:

df <- read.csv(file="path/to/your/file.csv", header=TRUE)
df.x <- df[df$Variables=='x', ]

R operates completely in memory, so an exception to what I said above might occur if you have a file whose total size is so massive that it cannot fit into memory, but for some reason the subset of interest can.