A bit of a follow up question of
R+arrow: Error when using the dataset API
Please have a look at the reprex at the end of the post. Essentially, I work on a data file without loading it into memory and I want to replace "" with "0" in a string.
In order to do so, I use the expression at
How do I gsub an empty "" string in R?
which works when I use it on a standard tibble, but not inside an arrow pipeline followed by collect(). I believe this did not happen with arrow 9.0. Does anyone know how to fix this?
Many thanks!
library(tidyverse)
library(arrow)
#>
#> Attaching package: 'arrow'
#> The following object is masked from 'package:utils':
#>
#> timestamp
ll <- c( "1000000", "10000000", "2000000" , "30000000" , "500000" ,
"5000000", "" , "Not Range")
df <- tibble(x=rep(ll, 1000), y=seq(8000))
write_tsv(df, "data.tsv")
data <- open_dataset("data.tsv", format="tsv",
skip_rows=1,
schema=schema(x=string(),
y=double())
)
test <- data |>
collect()
###I want to replace the "" with "0". I believe this worked with arrow 9.0
df2 <- data |>
mutate(x=gsub("^$","0",x) ) |>
collect()
df2 ### now I did not modify the "" entries in x
#> # A tibble: 8,000 × 2
#> x y
#> <chr> <dbl>
#> 1 "1000000" 1
#> 2 "10000000" 2
#> 3 "2000000" 3
#> 4 "30000000" 4
#> 5 "500000" 5
#> 6 "5000000" 6
#> 7 "" 7
#> 8 "Not Range" 8
#> 9 "1000000" 9
#> 10 "10000000" 10
#> # … with 7,990 more rows
df3 <- df |>
mutate(x=gsub("^$","0",x) )
df3 ## and this is fine
#> # A tibble: 8,000 × 2
#> x y
#> <chr> <int>
#> 1 1000000 1
#> 2 10000000 2
#> 3 2000000 3
#> 4 30000000 4
#> 5 500000 5
#> 6 5000000 6
#> 7 0 7
#> 8 Not Range 8
#> 9 1000000 9
#> 10 10000000 10
#> # … with 7,990 more rows
## How to fix this...I believe this issue did not arise with arrow 9.0.
sessionInfo()
#> R version 4.2.1 (2022-06-23)
#> Platform: x86_64-pc-linux-gnu (64-bit)
#> Running under: Debian GNU/Linux 11 (bullseye)
#>
#> Matrix products: default
#> BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
#> LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0
#>
#> locale:
#> [1] LC_CTYPE=en_GB.UTF-8 LC_NUMERIC=C
#> [3] LC_TIME=en_GB.UTF-8 LC_COLLATE=en_GB.UTF-8
#> [5] LC_MONETARY=en_GB.UTF-8 LC_MESSAGES=en_GB.UTF-8
#> [7] LC_PAPER=en_GB.UTF-8 LC_NAME=C
#> [9] LC_ADDRESS=C LC_TELEPHONE=C
#> [11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C
#>
#> attached base packages:
#> [1] stats graphics grDevices utils datasets methods base
#>
#> other attached packages:
#> [1] arrow_10.0.0 forcats_0.5.2 stringr_1.4.1 dplyr_1.0.10
#> [5] purrr_0.3.5 readr_2.1.3 tidyr_1.2.1 tibble_3.1.8
#> [9] ggplot2_3.3.6 tidyverse_1.3.2
#>
#> loaded via a namespace (and not attached):
#> [1] lubridate_1.8.0 assertthat_0.2.1 digest_0.6.30
#> [4] utf8_1.2.2 R6_2.5.1 cellranger_1.1.0
#> [7] backports_1.4.1 reprex_2.0.2 evaluate_0.17
#> [10] httr_1.4.4 highr_0.9 pillar_1.8.1
#> [13] rlang_1.0.6 googlesheets4_1.0.1 readxl_1.4.1
#> [16] R.utils_2.12.1 R.oo_1.25.0 rmarkdown_2.17
#> [19] styler_1.8.0 googledrive_2.0.0 bit_4.0.4
#> [22] munsell_0.5.0 broom_1.0.1 compiler_4.2.1
#> [25] modelr_0.1.9 xfun_0.34 pkgconfig_2.0.3
#> [28] htmltools_0.5.3 tidyselect_1.2.0 fansi_1.0.3
#> [31] crayon_1.5.2 tzdb_0.3.0 dbplyr_2.2.1
#> [34] withr_2.5.0 R.methodsS3_1.8.2 grid_4.2.1
#> [37] jsonlite_1.8.3 gtable_0.3.1 lifecycle_1.0.3
#> [40] DBI_1.1.3 magrittr_2.0.3 scales_1.2.1
#> [43] vroom_1.6.0 cli_3.4.1 stringi_1.7.8
#> [46] fs_1.5.2 xml2_1.3.3 ellipsis_0.3.2
#> [49] generics_0.1.3 vctrs_0.5.0 tools_4.2.1
#> [52] bit64_4.0.5 R.cache_0.16.0 glue_1.6.2
#> [55] hms_1.1.2 parallel_4.2.1 fastmap_1.1.0
#> [58] yaml_2.3.6 colorspace_2.0-3 gargle_1.2.1
#> [61] rvest_1.0.3 knitr_1.40 haven_2.5.1
Created on 2022-10-31 with reprex v2.0.2
