Store multiple outputs from each iteration of a for loop

Question

Given a fix path and a very limited directories from year. I'm trying to obtain each combination of path between this initial combination (fixPath - year) and the different, non-fixed and non-equally quantity, subdirectories contained in each combination of fixPath - year

fixPath <- "C:/Users/calcazar/Desktop/example"
year <- 2008:2010
pathVector <- paste(fixPath, year, sep = "/")
pathVector
[1] "C:/Users/calcazar/Desktop/example/2008" "C:/Users/calcazar/Desktop/example/2009"
[3] "C:/Users/calcazar/Desktop/example/2010"

My approach to solve this problem is use a for-loop:

Set the working directory with setwd(pathVector[1])
Scan the files (the subdirectories) with list.filesin that working directory and obtain each combination with: paste(pathVector[1], list.files(pathVector[1]), sep = "/")
Store this combinations in a vector and proceed with the next iteration

...but from each iteration of the loop I have a bunch of combinations and I can't figure out how to store more than one for each iteration. Here is my code:

for (i in seq_along(pathVector)) {
setwd(pathVector[i])
# here I only obtain the combination of the last iteration
# and if I use pathFinal[i] I only obtain the first combination of each iteration 
pathFinal <- paste(pathVector[i], list.files(pathVector[i]), sep = "/")
# print give me all the combinations
print(pathFinal[i])
}

So, how can store multiple values (combinations) from each iteration in a for loop?

I want a vector that contain all the combinations, for example:

 "C:/Users/calcazar/Desktop/example/2008/a"
 "C:/Users/calcazar/Desktop/example/2008/z"
 "C:/Users/calcazar/Desktop/example/2009/b"
 "C:/Users/calcazar/Desktop/example/2009/z"
 "C:/Users/calcazar/Desktop/example/2009/y"
 "C:/Users/calcazar/Desktop/example/2010/u"

does `list.files(full.names = TRUE, recursive = TRUE)` help with this task? — roman, Oct 19 '16 at 13:45
No, it doesn't work. Any sugestion in how can applied `full.names = TRUE` and `recursive = TRUE`? because it doesn't work with `list.files(fixPath, full.names = TRUE, recursive = TRUE)` — Cristóbal Alcázar, Oct 19 '16 at 14:19
`list.files(fixPath, recursive = TRUE, include.dirs = TRUE)` Works perfect! — Cristóbal Alcázar, Oct 19 '16 at 20:14

Bror Giesenbauer · Answer 1 · 2016-10-19T14:01:18.243

2

You might try to set up a vector beforehand and then use this part in your for loop:

append(VectorName, pathFinal[i])

you might try to include it in your existing code like this

pathFinal <- append(pathFinal, paste(pathVector[i], list.files(pathVector[i]), sep = "/"))

I haven't checked it, but it should add each new value to your desired vector. Also, I don't think you need to use setwd().

edited Oct 19 '16 at 14:01

answered Oct 19 '16 at 13:56

Bror Giesenbauer

23
3

or use the `foreach` library. – Henk Oct 19 '16 at 14:00
the append function does the job of encapsulate all the combinations in each iteration. You are right, the use of "setwd" is redundant. Thx! – Cristóbal Alcázar Oct 19 '16 at 14:29

score 1 · Accepted Answer · answered Oct 19 '16 at 14:03

1

Would something like this do what you want?

pathFinal = NULL

for (i in seq_along(pathVector)) {
  setwd(pathVector[i])

  pathFinal <- c(pathFinal, paste(pathVector[i], list.files(pathVector[i]), sep = "/"))

  print(pathFinal[i])
}

answered Oct 19 '16 at 14:03

User2321

2,952
23
46

1

the assign operator "c" does the job of encapsulate of all the combinations, but the print function only shows the combinations of the first iteration. By the way thanks for your answer! – Cristóbal Alcázar Oct 19 '16 at 14:24
Ok so we are halfway there! :) You would like to print in every iteration all the subdirectories? Because you can just print the paste argument (`paste(pathVector[i], list.files(pathVector[i]), sep = "/")` ). Or would you like to have a list that has for each iteration all the subdirectories? – User2321 Oct 19 '16 at 15:11

Store multiple outputs from each iteration of a for loop

2 Answers2

Linked