I can't replicate this problem using data.table 1.8.7 (installed about 3 weeks ago) on R version 2.15.2 (2012-10-26) Platform: i386-w64-mingw32/i386 (32-bit)
Michael ________________________________ From: [email protected] [[email protected]] on behalf of Victor Kryukov [[email protected]] Sent: Tuesday, 26 February 2013 9:26 AM To: [email protected] Subject: [datatable-help] Potential bug with sorting/summarizing by POSIXct and logical column 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
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