read.dta {foreign} | R Documentation |
Reads a file in Stata version 5-8 or 7/SE binary format into a data frame.
read.dta(file, convert.dates = TRUE, tz = NULL, convert.factors = TRUE, missing.type = FALSE, convert.underscore=TRUE, warn.missing.labels=TRUE)
file |
a filename as a character string. |
convert.dates |
Convert Stata dates to Date class? |
tz |
Previously used to specify time zone. Now deprecated. |
convert.factors |
Use Stata value labels to create factors? (version 6.0 or later). |
missing.type |
For version 8 only, store information about different types of missing data? |
convert.underscore |
Convert "_" in Stata variable names
to "." in R names? |
warn.missing.labels |
Warn if a variable is specified with value labels and those value labels are not present in the file. |
The variables in the Stata data set become the columns of the data frame. Missing values are correctly handled. The data label, variable labels, and timestamp are stored as attributes of the data frame. Nothing is done with variable characteristics.
Optionally, Stata dates (%d formats) are converted to R's
Date
class and variables with Stata value labels are
converted to factors. Ordinarily, read.dta
will not convert
a variable to a factor unless a label is present for every level. Use
convert.factors=NA
to override this. In any case the value
label and format information is stored as attributes on the returned data frame.
Stata 8.0 has 27 different missing data values. If missing.type
is TRUE
a separate list is created with the same variable
names as the loaded data. For string variables the list value is
NULL
. For other variables the value is NA
where the
observation is not missing and 0-26 when the observation is
missing. This is attached as the code{"missing"} attribute of the
returned value.
The option to allow underscores in variable names may become the default in future versions now that R supports their use.
a data frame
Thomas Lumley
Stata Users Manual (versions 5 & 6), Programming manual (version 7), or online help (version 8) describe the format of the files.
write.dta
,
attributes
Date
factor
data(swiss) write.dta(swiss,swissfile<-tempfile()) read.dta(swissfile)