Generate sequence in for loop

Question

This has probably been answered, but I couldn't find the solution to my specific problem: I am looking for a certain file type (for eg. jpeg) and printing to the user a message using the message() function. But along with the message I want to print a sequence. The output should read:

1. Found filename at System time.
2. Found filename2 at System time.

Unfortunately, my output is:

1 Found filename at System time
2 Found filename at System time
1 Found filename2 at System time
2 Found filename2 at System time

My Code:

library(tools)
setwd("/Users/RLearner/Desktop/TEMP")
a<-list.files(getwd(), recursive=TRUE)
for (f in a)
  for (i in 1:length(a))
    if (file_ext(f)=="jpeg")
    {
      message(paste(i, "Found", f, "-", Sys.time(), sep = " "))
    }

What am I doing wrong?

score 4 · Accepted Answer · 2015-10-08 08:24:01Z

4

Isn't the following enough?

setwd("/Users/RLearner/Desktop/TEMP")
a <- list.files(getwd(), pattern="*jpeg$", recursive=TRUE)

out <- paste(seq_along(a), "Found", "-", a, Sys.time(), sep = " ")

Edit

I couldn't find a solution by simply feed message with out. There is still need for a for loop. If someone could find a wrapping, please feel free to edit.

for (ii in out){
  message(ii)
}

edited Oct 8, 2015 at 8:24

answered Oct 8, 2015 at 8:03

user3710546

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4 Comments

CuriousBeing Over a year ago

Thanks @Pascal. But I want to use the message function and display to the user. The code works but when I wrap it with message it doesn't work :( <br> This little code is going to be part of my very long code which displays messages to user at certain points. I have re-edited my main question and put focus on message.

CuriousBeing Over a year ago

Thanks so much for your time @Pascal. I have posted a solution below. I have done it using the traditional way and using 1 for loop now.

user3710546 Over a year ago

There is also one loop in my solution.

user3710546 Over a year ago

I couldn't find a clean solution without the for loop. It is annoying me.

CuriousBeing · Accepted Answer · 2015-10-08 08:26:44Z

1

I figured it out! If i declare a variable i<-0 and then increment it in the if statement, it works: My code:

library(tools)
setwd("/Users/RLearner/Desktop/TEMP")
a<-list.files(getwd(), recursive=TRUE)
i<-0
for (f in a)
if (file_ext(f)=="jpeg")
{
message(paste(i+1, "Found", f, "-", Sys.time(), sep = " "))
i<-i+1
}

answered Oct 8, 2015 at 8:26

CuriousBeing

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