fromStataTime: Convert Stata date-times to R classes

In jrnold/stataXml: Read and write Stata xml files.

Description

Converts numeric values corresponding to a Stata date-time format to a Date or POSIXct object.

Usage

fromStataTime(x, fmt, tz = "")

Arguments

x	numeric.
fmt	character. Stata date-time format: '%tc', '%tC', '%td', '%tm', '%tq', '%th', '%tg', or '%ty'.
tz	character. Time zone.

Details

Stata stores dates-time variables as units of time since Jan 1, 1960. The unit of time used depends on the Stata format. One unit in variable formatted '%tc', corresponds to 1 millisecond; in '%td', one day; in '%tm', one month, etc.

This function is useful for converting date-time variables imported from a Stata dataset, such as from read.dta or read.stataXml, into the correct R dates values.

Stata does not use time zones in date-time values. If a time zone is important for conversion, supply a time zone in the tz argument.

The Stata '%tC' format includes leap seconds. Since R does not use leap seconds in the POSIXt classes, values of leap seconds are handled according to the POSIX standard when converting '%tC' values to POSIXct.

Value

If fmt is '%tc' or '%tC', then a POSIXct object is returned. If fmt is '%td', '%tm', '%tq', '%th', then a Date object is returned. If fmt is '%tg' or '%ty', then a numeric object object is returned.

Author(s)

Jeffrey Arnold

References

For details of how Stata represents dates and times, see Stata help for dates_and_times, online at http://www.stata.com/help.cgi?dates_and_times.

See Also

asStataTime, Date, POSIXt

Examples

## clock to POSIXt
fromStataTime(-1:1, '%tc')

## dates to Date
fromStataTime(-1:1, '%td')

## months 
fromStataTime(-1:1, '%tm')

## quarters
fromStataTime(-1:1, '%tq')

## half-years
fromStataTime(-1:1, '%th')

## years
fromStataTime(1959:1960, '%ty')

jrnold/stataXml documentation built on May 20, 2019, 2:06 a.m.