write.dta {foreign}R Documentation

Write Files in Stata Binary Format


Writes the data frame to file in the Stata version 6.0 or 7.0 binary format. Does not write matrix variables.


write.dta(dataframe, file, version = 6,
          convert.dates = TRUE, tz = "GMT",
          convert.factors = c("labels", "string", "numeric", "codes"))


dataframe a data frame.
file character string giving filename.
version Stata version: 6 and 7 are supported.
convert.dates Convert POSIXt objects to Stata dates?
tz timezone for date conversion
convert.factors how to handle factors


The major differences between Stata versions is that 7.0 allows 32-character variable names. The abbreviate function is used to trim long variables to the permitted length. A warning is given if this is needed and it is an error for the abbreviated names not to be unique.

The columns in the data frame become variables in the Stata data set. Missing values are correctly handled. Optionally, R date/time objects (POSIXt classes) are converted into the Stata format. This loses information – Stata dates are in days since 1960-1-1. POSIXct objects can be written without conversion but will not be understood as dates by Stata; POSIXlt objects cannot be written without conversion.

There are four options for handling factors. The default is to use Stata value labels for the factor levels. With convert.factors="string", the factor levels are written as strings. With convert.factors="numeric" the numeric values of the levels are written, or NA if they cannot be coerced to numeric. Finally, convert.factors="codes" writes the underlying integer codes of the factors. This last used to be the only available method and is provided largely for backwards compatibility.

For Stata 8 or 9 use version=7 – the only advantage of Stata 8 format is that it can represent multiple different missing value types, and R doesn't have them.




Thomas Lumley


Stata 6.0 Users Manual, Stata 7.0 Programming manual, Stata 8.0, 9.0 online help describe the file formats.

See Also

read.dta, attributes, DateTimeClasses, abbreviate


write.dta(swiss, swissfile <- tempfile())

[Package foreign version 0.8-20 Index]