write.dta {foreign} | R Documentation

## Write Files in Stata Binary Format

### Description

Writes the data frame to file in the Stata binary format. Does not write array variables unless they can be `drop`-ed to a vector.

### Usage

    write.dta(dataframe, file, version = 7L,
              convert.dates = TRUE, tz = "GMT",
              convert.factors = c("labels", "string", "numeric", "codes"))

### Arguments

`dataframe` | a data frame.
`file` | character string giving filename.
`version` | integer: Stata version: 6, 7, 8 and 10 are supported, and 9 is mapped to 8, 11 to 10.
`convert.dates` | Convert `Date` and `POSIXt` objects to Stata dates?
`tz` | timezone for date conversion
`convert.factors` | how to handle factors

### Details

The major differences between file formats in Stata versions is that version 7.0 and later allow 32-character variable names (5 and 6 were restricted to 8-character name). 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 handled correctly.

Unless deselected by argument `convert.dates`, R date and date-time objects (`POSIXt` classes) are converted into the Stata format. For date-time objects this may lose 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 later use the default `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. Stata 10/11 allows longer format lists, but R does not make use of them.

Note that the Stata formats are documented to use ASCII strings – R does not enforce this, but use of non-ASCII character strings will not be portable as the encoding is not recorded. Up to 244 bytes are allowed in character data, and longer strings will be truncated with a warning.

Stata uses some large numerical values to represent missing values. This function does not currently check, and hence integers greater than `2147483620` and doubles greater than `8.988e+307` may be misinterpreted by Stata.

### Value

`NULL`

### Author(s)

Thomas Lumley and R-core members

### References

Stata 6.0 Users Manual, Stata 7.0 Programming manual, Stata online help (version 8 and later, also http://www.stata.com/help.cgi?dta and http://www.stata.com/help.cgi?dta_113) describe the file formats.

### See Also

`read.dta`, `attributes`, `DateTimeClasses`, `abbreviate`

### Examples

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

[Package foreign version 0.8-50 Index]