arrange date characters in R

user_11748972 0
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I am working with many csv files that are labelled with the month of year in brackets. For example:

files_names <- list.files("data/", recursive = TRUE, full.names = TRUE)

[1] "data/BOC_All_ATMImage_(Aug 2020).txt" "data/BOC_All_ATMImage_(Aug 2021).txt"
[3] "data/BOC_All_ATMImage_(Feb 2021).txt" "data/BOC_All_ATMImage_(Feb_2020).txt"
[5] "data/BOC_All_ATMImage_(May 2021).txt" "data/BOC_All_ATMImage_(Nov 2019).txt"

column_names <- files_names %>%
  str_extract(., "(?<=\\().*?(?=\\))") %>%
  str_to_lower() %>%
  str_replace(., " ", "_")

"aug_2020" "aug_2021" "feb_2021" "feb_2020" "may_2021" "nov_2019"

I am using the map2 function in purrr to process the csv files and setting a column name using files_names and column_names in a loop.

data <-
  map2(files_names, column_names,
       ~ read_csv(.x, guess_max = 50000) %>%
         mutate(
           day = 01,
           month_year = str_extract(.x, "(?<=\\().*?(?=\\))"),
           date_dmy = paste0(day, "-", month_year),
           date = dmy(date_dmy),
           "{.y}" := 1
         ),
       .id = "group" 
  )

I need to figure out how to arrange this list so each data set is in chronological order. One approach is to arrange the initial character vectors (files_names and column_names) before feeding them into to loop. Or perhaps it would be easier to simply arrange the data list so the data frames are chronologically ordered? I have created a date variable in each data frame so this could be another approach, but I'm not sure how to reorder the list by a date variable.

purrr dplyr r
4 Answers

We can use str_match to search for months and years. After that, use some dplyr to clean the data. To arrange the months I thought of using a factor.

library(tidyverse)

files_names <-
  c(
    "data/BOC_All_ATMImage_(Aug 2020).txt", "data/BOC_All_ATMImage_(Aug 2021).txt",
    "data/BOC_All_ATMImage_(Feb 2021).txt", "data/BOC_All_ATMImage_(Feb_2020).txt",
    "data/BOC_All_ATMImage_(May 2021).txt", "data/BOC_All_ATMImage_(Nov 2019).txt"
  )

factor_w_month <- partial(factor, levels = )
months <- partial(factor, levels = (c("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec")))

files_names %>%
  str_match(".*_\\((.*)[ _](\\d+)\\)\\.txt$") %>%
    as.data.frame() %>%
    mutate(V2 = months(V2)) %>%
    arrange(V3, V2) %>% 
    transmute(files_names = V1, column_names = str_to_lower(str_c(V2, '_', V3)))
#>                            files_names column_names
#> 1 data/BOC_All_ATMImage_(Nov 2019).txt     nov_2019
#> 2 data/BOC_All_ATMImage_(Feb_2020).txt     feb_2020
#> 3 data/BOC_All_ATMImage_(Aug 2020).txt     aug_2020
#> 4 data/BOC_All_ATMImage_(Feb 2021).txt     feb_2021
#> 5 data/BOC_All_ATMImage_(May 2021).txt     may_2021
#> 6 data/BOC_All_ATMImage_(Aug 2021).txt     aug_2021

Created on 2021-12-20 by the reprex package (v2.0.1)

user_111687660

I think the following solution could also help you sort your dates before starting to read them into R:

library(dplyr)
library(stringr)

files_names %>%
  enframe() %>%
  mutate(date = str_extract(value, "(?<=\\().*(?=\\))"), 
         date = paste(str_extract(date, "\\d+"), str_extract(date, "[[:alpha:]]+"), "01", 
                      sep = "-"), 
         date = as.Date(date, format = "%Y-%b-%d")) %>%
  arrange(desc(date))

# A tibble: 6 x 3
   name value                                date      
  <int> <chr>                                <date>    
1     2 data/BOC_All_ATMImage_(Aug 2021).txt 2021-08-01
2     5 data/BOC_All_ATMImage_(May 2021).txt 2021-05-01
3     3 data/BOC_All_ATMImage_(Feb 2021).txt 2021-02-01
4     1 data/BOC_All_ATMImage_(Aug 2020).txt 2020-08-01
5     4 data/BOC_All_ATMImage_(Feb_2020).txt 2020-02-01
6     6 data/BOC_All_ATMImage_(Nov 2019).txt 2019-11-01

And some tiny hint about the regex you used, I think you don't need to make .* part lazy.

user_143145200

By parsing and ordering the date from column_names , you can arrange your files_names in chronological order and process your files from there

files_names <- list.files("data/", recursive = TRUE, full.names = TRUE)

column_names <- files_names %>%
  str_extract(., "(?<=\\().*?(?=\\))") %>%
  str_to_lower() %>%
  str_replace(., " ", "_")


files_names <- files_names[
order(readr::parse_date(column_names,"%b_%Y"))]
files_names
[1] "data/BOC_All_ATMImage_(Nov 2019).txt"
[2] "data/BOC_All_ATMImage_(Feb_2020).txt"
[3] "data/BOC_All_ATMImage_(Aug 2020).txt"
[4] "data/BOC_All_ATMImage_(Feb 2021).txt"
[5] "data/BOC_All_ATMImage_(May 2021).txt"
[6] "data/BOC_All_ATMImage_(Aug 2021).txt"
user_94240880

I can't really run your code without the csv files, but it looks like you've already got a list of tibbles, and you've already added a date column using the fragment from the file name. In this case, you just need

data %>% bind_rows() %>% arrange(date)

to get a single tibble, but with the rows ordered based on the date from the filename.

user_127443230
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