[datatable-help] Potential bug with sorting/summarizing by POSIXct and logical column

[Victor Kryukov]

Hello,

I've encounted what looks like a bug while sorting by POSIXct and logical
column, which may or may not be related to the following bug:

https://r-forge.r-project.org/tracker/index.php?func=detail&aid=2552&group_id=240&atid=975

Here are all the details:
http://stackoverflow.com/questions/15077232/data-table-not-summarizing-properly-by-two-columns

Here is the test case:

    # First some data
    data <- data.table(structure(list(
      month = structure(c(1356998400, 1356998400, 1356998400,
                          1359676800, 1354320000, 1359676800, 1359676800,
1356998400, 1356998400,
                          1354320000, 1354320000, 1354320000, 1359676800,
1359676800, 1359676800,
                          1356998400, 1359676800, 1359676800, 1356998400,
1359676800, 1359676800,
                          1359676800, 1359676800, 1354320000, 1354320000),
class = c("POSIXct",

         "POSIXt"), tzone = "UTC"),
      portal = c(TRUE, TRUE, FALSE, TRUE,
                 TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, TRUE, FALSE, TRUE,
FALSE,
                 TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE,
TRUE, TRUE
      ),
      satisfaction = c(10L, 10L, 10L, 9L, 10L, 10L, 9L, 10L, 10L,
                       9L, 2L, 8L, 10L, 9L, 10L, 10L, 9L, 10L, 10L, 10L,
9L, 10L, 9L,
                       10L, 10L)),
                      .Names = c("month", "portal", "satisfaction"),
                      row.names = c(NA, -25L), class = "data.frame"))

    # Summarizing by month, portal with tapply works:

    > tapply(data$satisfaction, list(data$month, data$portal), mean)
    FALSE      TRUE
    2012-12-01   8.5  8.000000
    2013-01-01  10.0 10.000000
    2013-02-01   9.0  9.545455

    # Summarizing with 'by' argument of data.table does not:

    > data[, mean(satisfaction), by = 'month,portal']>
      data[, mean(satisfaction), by = list(month, portal)]
    month portal        V1
    1: 2013-01-01  FALSE 10.000000
    2: 2013-02-01   TRUE  9.000000
    3: 2013-01-01   TRUE 10.000000
    4: 2012-12-01  FALSE  8.500000
    5: 2012-12-01   TRUE  7.333333
    6: 2013-02-01   TRUE  9.666667
    7: 2013-02-01  FALSE  9.000000
    8: 2012-12-01   TRUE 10.000000

    # Summarizing only this year's data works:
    data[month >= ymd(20130101), mean(satisfaction), by = 'month,portal']
    month portal        V1
    1: 2013-01-01   TRUE 10.000000
    2: 2013-01-01  FALSE 10.000000
    3: 2013-02-01   TRUE  9.545455
    4: 2013-02-01  FALSE  9.000000

Yours Sincerely,
Victor Kryukov
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.r-forge.r-project.org/pipermail/datatable-help/attachments/20130225/45b99e3e/attachment.html>