Matt Parker mattparker-wf
mattparker-wf
/ get_monday.r
Created
February 20, 2015 00:18
Get the Monday or Sunday preceding a given date
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| # Source: the masterful Marc Schwartz, in this R-help thread: | |
| # http://r.789695.n4.nabble.com/previous-monday-date-td3786395.html | |
| # Getting the Monday preceding any date | |
| # See ?cut.Date for additional info | |
| as.Date(cut(Sys.Date(), breaks = "weeks")) | |
| # Alternatively, the preceding Sunday: | |
| as.Date(cut(Sys.Date(), breaks = "weeks", start.on.monday = FALSE) |
mattparker-wf
/ collapse_time_idea.r
Created
November 7, 2014 16:25
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| # An alternative approach | |
| # First - a quick function for counting unique values that excludes NAs | |
| count.unique <- function(x) { length(unique(x[!is.na(x)])) } | |
| # Compare: | |
| length(unique(NA)) | |
| count.unique(NA) | |