How to open a series of files with the same path and plot them

Question

I have a series of txt files I would like to plot in R, but I need help constructing a for loop to automate this for when I have dozens of files.

My current script, which is fine for a few files, is simply this two-line repetitive code:

data <- read.table("/path/filename1.txt")
    plot(data, type = 'l', ylim=c(0,100), xlim = c(350,900))

data2 <- read.table("/path/filename2.txt")
    points(data, type = 'l', ylim=c(0,100), xlim = c(350,900))

data3 <- read.table("/path/filename3.txt")
    points(data, type = 'l', ylim=c(0,100), xlim = c(350,900))

data3 <- read.table("/path/filename3.txt")
    points(data, type = 'l', ylim=c(0,100), xlim = c(350,900))

I am certain there is a simpler way to do this using a for loop, but I am unfamiliar with R and not sure how to accomplish this.

Thank you for the help!

This is pretty close to a [duplicate question](https://stackoverflow.com/questions/19852774/how-to-automatically-plot-many-csv-files-with-the-same-number-of-rows-and-column) and [this question](https://stackoverflow.com/questions/7311372/merging-data-from-many-files-and-plot-them/7311591) also, and [this one](https://stackoverflow.com/questions/18826985/open-and-plot-multiple-files). — lmo, Apr 16 '18 at 16:55

Jilber Urbina · Answer 1 · 2018-04-16T16:53:00.723

2

Since I don't have your files, this code is not tested, but it could work.

First set your working directory and then apply the following....

Read all files

Files <- lapply(list.files(pattern = "\\.txt$"), read.table)

Plot them..

lapply(Files, function(x) points(x, type = 'l', ylim=c(0,100), xlim = c(350,900)))

edited Apr 16 '18 at 16:53

answered Apr 16 '18 at 16:50

Jilber Urbina

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I think `plot(Files[[1]])` should be called first before `lapply(Files[[-1]], function(x) points(x))`. – DJack Apr 16 '18 at 17:11
To plot silently in base R and have a compact syntax in the style of lapply we can use `Vectorize` – moodymudskipper Apr 16 '18 at 19:34

score 0 · Answer 2 · answered Apr 16 '18 at 16:50

You can do so using a for loop as you suggested, like so:

files <- c('/path/filename1.txt', '/path/filename2.txt')

for(file in files)
{
  data <- read.table(file)
  plot(data, type = 'l', ylim=c(0,100), xlim = c(350,900))
}

In this case, you are storing your file paths in a vector called files, and then performing the same action on each individual member of files.

How to open a series of files with the same path and plot them

2 Answers2