Create a monthly adjustable program

[ramgouveia]

I have the following code:

DATAFRAMEINPUT <- read.csv2("R:/2018_01_F2.csv", header=TRUE)
DATAFRAMEINPUT <- read.csv2("R:/2018_02_F2.csv", header=TRUE)
DATAFRAMEINPUT <- read.csv2("R:/2018_03_F2.csv", header=TRUE)

Instead of 2018_01 I want n-36, i.e., the 36th previous month.
Instead of 2018_02 I want n-35, i.e., the 35th previous month.
Instead of 2018_03 I want n-34, i.e., the 34th previous month.

I want to define a base month on the code and then count backwards 36 months.

I want to create a monthly routine program.

Can you help me writing the proper code?

[jonspring]

We want two things:

1. figure out what month is X months ago
2. format that date into a file name string we can use

Here's a function to do those two things:

library(lubridate)
file_namer <- function(months_prior) {
  current_month <- floor_date(Sys.Date(), "month")
  dest_month <- current_month %m-% months(months_prior)
  paste0("R:/", year(dest_month), "_", month(dest_month), "_F2.csv")
}

floor_date(Sys.Date(), "month") will output the 1st of the current month. I calculate that to avoid any complications around different-length months. All months have a 1st so that should be predictable.

Then I use lubridate's odd-looking %m-% operator which subracts months (basically equivalent to using negative numbers with Excel's EDATE function, as far as I can tell).

Finally, I paste the results together into a string like we need.

We can test it out:

file_namer(0)
[1] "R:/2021_4_F2.csv"
file_namer(12)
[1] "R:/2020_4_F2.csv"
file_namer(36)
[1] "R:/2018_4_F2.csv"

We could use it like

DATAFRAMEINPUT <- read.csv2(filenamer(36), header=TRUE)
DATAFRAMEINPUT <- read.csv2(filenamer(35, header=TRUE)
DATAFRAMEINPUT <- read.csv2(filenamer(34), header=TRUE)

(I assume you are actually saving the results to different files, otherwise the 2nd line will just overwrite the result of the 1st line, and then again with the 3rd line.)

[ramgouveia]

I have run this code and solved the problem.

# Defining Variables
MESANALISE <- "01_2021"
# MESINICIAL - Substituir na linha 16 o primeiro dia desse mês
FLUXO <- "F1"
FLUXO2 <- "FL1"

# Creates a vector with the name of the 36 files to import
DATAFRAMEINPUTFILES <- seq(from = as.Date("2018/01/01"),
                           by = "month",
                           length.out = 36)
DATAFRAMEINPUTFILES <- substr(DATAFRAMEINPUTFILES, 1, 7)
DATAFRAMEINPUTFILES <- paste(substr(DATAFRAMEINPUTFILES, 6, 7), substr(DATAFRAMEINPUTFILES, 1, 4), sep = "_")
DATAFRAMEINPUTFILES <- paste0("R:/", FLUXO2, "/", DATAFRAMEINPUTFILES, "_", FLUXO, ".csv")

# Import the files
for(i in 1:length(DATAFRAMEINPUTFILES)) {                             
  assign(paste0("DATAFRAMEINPUT_COM_TT_N_", i),                                  
         read.csv2(DATAFRAMEINPUTFILES[i]))
}