vroom_fwf not reading the first line?

[sysilviakim]

Hello team,

Thank you for the amazing package! I have an importing issue---I'm sure I'm doing something silly, but I can't quite figure it out. Both read_fwf and vroom_fwf are producing files that lack one line (the first line, to be precise) when importing fixed-width files. Edit: it only does this when n_max is specified as a value other than Inf, or when the file is a local file in a Windows machine: see Stack Overflow post here.

There are two files:

• test.csv
• vroom_fwf_test.txt

Suppose that the fixed-width file and the CSV file are at the root directory. The code I used is (a part of a larger codebase)

library(dplyr)
library(vroom)
library(data.table)

test <- fread(
  "test.csv",
  strip.white = TRUE, header = FALSE, blank.lines.skip = TRUE
) %>%
  filter(!is.na(V2)) %>%
  mutate(V1 = gsub(" |\\(", ".", gsub("\\)", "", V1)))
  
## gives one line
vroom::vroom_fwf(
  "vroom_fwf_test.txt", fwf_widths(test$V3, test$V1),
  n_max = 1000, col_types = cols(.default = "c"), id = "file_name"
)

This will only produce one row of data. But there are two lines in this raw file, as evidenced by

writeLines(read_lines(path)) ## two lines

which produces two lines as expected. If I leave only one line in the raw data, it'll produce zero imported rows.

Now, if n_max = Inf as in the default, it's fine:

## gives two lines as it should
vroom::vroom_fwf(
  "vroom_fwf_test.txt", fwf_widths(test$V3, test$V1),
  n_max = Inf, col_types = cols(.default = "c"), id = "file_name"
)

Even with n_max = 1000 specified, the following works fine, too: the original files have been uploaded to GitHub and are being directly called from there:

## gives two lines as it should
vroom::vroom_fwf(
  file = "https://github.com/tidyverse/vroom/files/12156789/vroom_fwf_test.txt",
  col_positions = with(
    read.csv(
      "https://github.com/tidyverse/vroom/files/12156786/test.csv",
      header = F
    ), vroom::fwf_widths(V3, V1)
  ),
  n_max = 1000,
  col_types = vroom::cols(.default = "c"),
  id = "file_name"
)

I am not sure where I've gone wrong. They are literally the same files, and I've checked that col_positions is not the problem. Perhaps it is a line-ending issue? My session info is as follows:

R version 4.2.2 (2022-10-31 ucrt)
Platform: x86_64-w64-mingw32/x6
[test.csv](https
[vroom_fwf_test.txt](https://github.com/tidyverse/vroom/files/12156789/vroom_fwf_test.txt)
://github.com/tidyverse/vroom/files/12156786/test.csv)
4 (64-bit)
Running under: Windows 10 x64 (build 19045)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.utf8 
[2] LC_CTYPE=English_United States.utf8   
[3] LC_MONETARY=English_United States.utf8
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.utf8    

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base     

other attached packages:
 [1] sf_1.0-9           censusxy_1.1.1     tidygeocoder_1.0.5
 [4] foreign_0.8-83     lubridate_1.9.0    timechange_0.1.1  
 [7] data.table_1.14.8  vroom_1.6.0        janitor_2.1.0     
[10] readxl_1.4.1       assertthat_0.2.1   here_1.0.1        
[13] stringi_1.7.8      forcats_0.5.2      stringr_1.5.0     
[16] dplyr_1.1.0        purrr_1.0.0        readr_2.1.3       
[19] tidyr_1.2.1        tibble_3.1.8       ggplot2_3.4.0     
[22] tidyverse_1.3.2    plyr_1.8.8         MASS_7.3-58.1     

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.9          class_7.3-20        rprojroot_2.0.3    
 [4] utf8_1.2.2          R6_2.5.1            cellranger_1.1.0   
 [7] backports_1.4.1     reprex_2.0.2        e1071_1.7-12       
[10] httr_1.4.4          pillar_1.8.1        rlang_1.0.6        
[13] googlesheets4_1.0.1 rstudioapi_0.14     googledrive_2.0.0  
[16] bit_4.0.5           munsell_0.5.0       proxy_0.4-27       
[19] broom_1.0.2         compiler_4.2.2      modelr_0.1.10      
[22] pkgconfig_2.0.3     tidyselect_1.2.0    fansi_1.0.3        
[25] crayon_1.5.2        tzdb_0.3.0          dbplyr_2.2.1       
[28] withr_2.5.0         grid_4.2.2          jsonlite_1.8.4     
[31] gtable_0.3.1        lifecycle_1.0.3     DBI_1.1.3          
[34] magrittr_2.0.3      units_0.8-1         scales_1.2.1       
[37] KernSmooth_2.23-20  cli_3.6.0           renv_0.16.0        
[40] fs_1.5.2            snakecase_0.11.0    xml2_1.3.3         
[43] ellipsis_0.3.2      generics_0.1.3      vctrs_0.5.2        
[46] tools_4.2.2         bit64_4.0.5         glue_1.6.2         
[49] hms_1.1.2           parallel_4.2.2      colorspace_2.0-3   
[52] gargle_1.2.1        classInt_0.4-8      rvest_1.0.3        
[55] haven_2.5.1   

Has anybody encountered a similar problem? Thank you very much.

[jennybc]

Do the people giving this a thumbs up also have different examples of this problem? If so, please share! @bernardlf @jay-sf

[jay-sf]

@jennybc Found alternative solution there: https://stackoverflow.com/a/76759892/6574038
Cheers! J