EVOLUTION-MANAGER
Edit File: datetimes.Rmd
--- title: "Dates and times" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{Date times} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8} --- ## Formats There are three common formats across SAS, SPSS and Stata. Date (number of days) * SAS: MMDDYY, DDMMYY, YYMMDD, DATE * Spss: n/a * Stata: %td Time (number of seconds): * SAS: TIME, HHMM, TOD * Spss: TIME, DTIME * Stata: n/a DateTime (number of seconds): * SAS: DATETIME * Spss: DATE, ADATE, SDATE, DATETIME (as milliseconds) * Stata: %tc, %tC ## Offsets Dates and date times use a difference offset to R: * SAS: 1960-01-01 (`r -as.integer(as.Date("1960-01-01"))` days) * Spss: 1582-10-14. (`r -as.integer(as.Date("1582-10-14"))` days) * Stata: 1960-01-01. (`r -as.integer(as.Date("1960-01-01"))` days) ## References * SAS: <https://v8doc.sas.com/sashtml/lrcon/zenid-63.htm>, <http://support.sas.com/documentation/cdl/en/etsug/60372/HTML/default/viewer.htm> * Spss: <http://www-01.ibm.com/support/knowledgecenter/#!/SSLVMB_20.0.0/com.ibm.spss.statistics.help/idh_idd_dtwz_learn.htm> <http://www-01.ibm.com/support/knowledgecenter/#!/SSLVMB_20.0.0/com.ibm.spss.statistics.help/syn_date_and_time_date_time_formats.htm> * Stata: <http://www.stata.com/manuals13/u24.pdf>