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Sascha commented on ARROW-7028: ------------------------------- Jup, agree. Just wanted to say, depending on what you put in your Date class, when saving and loading as parquet you may also run into problems independent of the dplyr-verse as long as parquet converts the numerics to integer... > [R] Date roundtrip results in different R storage mode > ------------------------------------------------------ > > Key: ARROW-7028 > URL: https://issues.apache.org/jira/browse/ARROW-7028 > Project: Apache Arrow > Issue Type: Bug > Components: R > Affects Versions: 0.15.0 > Reporter: Sascha > Priority: Major > Attachments: image-2019-10-30-23-08-17-296.png > > > When saving R-dataframes with parquet and loading them again, the internal > representation of Dates changes, leading e.g. to errors when comparing them > in dplyr::if_else. > {code} > library(dplyr) > #> > #> Attaching package: 'dplyr' > #> The following objects are masked from 'package:stats': > #> > #> filter, lag > #> The following objects are masked from 'package:base': > #> > #> intersect, setdiff, setequal, union > tmp = tempdir() > dat = tibble(tag = as.Date("2018-01-01")) > dat2 = tibble(tag2 = as.Date("2019-01-01")) > arrow::write_parquet(dat, file.path(tmp, "dat.parquet")) > dat = arrow::read_parquet(file.path(tmp, "dat.parquet")) > typeof(dat$tag) > #> [1] "integer" > typeof(dat2$tag2) > #> [1] "double" > bind_cols(dat, dat2) %>% > mutate(comparison = if_else(TRUE, tag, tag2)) > #> `false` must be a `Date` object, not a `Date` object > {code} > Created on 2019-10-30 by the [reprex package](https://reprex.tidyverse.org) > (v0.3.0) -- This message was sent by Atlassian Jira (v8.3.4#803005)