0

I have data from Jan 2021 - Feb 2022 (the names data like CARD_202101, CARD_202102, CARD_202103 until CARD_202202) each data contain variables:

  • CIF
  • Date
  • Descriptions

How can I make function in R. so I just can have CIF and Date variables for all datasets from Jan 2021 - Feb2022

example:

CARD_202101 <- data.frame(CIF = c(1,2,3), Date = c('2021-01-01', '2021-01- 
               02','2021-01-01'), Descriptions = c("a", "b", "c"))
CARD_202102 <- data.frame(CIF = c(1,6,3), Date = c('2021-02-01', '2021-02- 
               02','2021-01-01'), Descriptions = c("a", "b", "c"))
....


CARD_202202 <- data.frame(CIF = c(4,2,3), Date = c('2022-02-01', '2022-02- 
               02','2022-02-01'), Descriptions = c("a", "b", "c"))

I just want each dataset just only contain CIF and Date Variables, like

CARD_202101 <- data.frame(CIF = c(1,2,3), Date = c('2021-01-01', '2021-01- 
               02','2021-01-01'))

CARD_202102 <- data.frame(CIF = c(1,6,3), Date = c('2021-02-01', '2021-02- 
               02','2021-01-01'))
....


CARD_202202 <- data.frame(CIF = c(4,2,3), Date = c('2022-02-01', '2022-02- 
               02','2022-02-01'))

I need looping through all dataset
Lilac_Mimo
  • 315
  • 5
  • 2
    It would be best to provide a [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) with your question. You might want to look at the [dplyr](https://cran.r-project.org/web/packages/dplyr/vignettes/dplyr.html) when dealing with data frame. – Bushidov Sep 12 '22 at 08:08
  • I ave been edited. Thank you – Lilac_Mimo Sep 20 '22 at 10:09

1 Answers1

0

I will asume few things first:

  1. naming convention of data is like: it starts with CARD_ and followed by 6 digits
  2. I can use package
  3. objects are in global environment

If so i recomend loop through all the object that meet naming convention and bind them using data.table::rbindlist like this:

bind_datasets <- function()
{
    data.table::rbindlist(
        l = lapply(
            X = ls(envir = globalenv(), pattern = "^(CARD_)\\d{6}$"),
            FUN = function(i)
            {
                res <- get(x = i, envir = globalenv())
                res <- subset(x = res, select = c("CIF", "Date"))
                return(res)
            }
        )
    )    
}

This function:

  1. search global environment for object named with established pattern
  2. for each object retrieves CIF and Date column
  3. bind object one after another.

EDIT:

After your comment I think the answer is the code below:

# find all the data in global environment which comply with a pattern
datasets <- ls(envir = globalenv(), pattern = "^(CARD_)\\d{6}$")
# loop through it and each time assign to them their subset
for (dst in datasets)
{
    res <- get(x = dst, envir = globalenv())
    assign(
        x = dst, 
        value = subset(x = res, select = c("CIF", "Date")), 
        envir = globalenv()
    )
}
Dominik Żabiński
  • 285
  • 1
  • 7