help fdasave, help fdause, dialogs: fdasave fdause
help fdadescribe
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Title
[D] fdasave -- Save and use datasets in FDA (SAS XPORT) format
Syntax
Save data in memory in FDA format
fdasave filename [if] [in] [, fdasave_options]
fdasave varlist using filename [if] [in] [, fdasave_options]
Read SAS XPORT file into Stata
fdause filename [, fdause_options]
Describe contents of SAS XPORT Transport file
fdadescribe filename [, member(mbrname)]
fdasave_options description
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Main
rename rename variables and value labels to meet SAS
XPORT restrictions
replace overwrite files if they already exist
vallabfile(xpf) save value labels in formats.xpf
vallabfile(sascode) save value labels in SAS command file
vallabfile(both) save value labels in formats.xpf and in a SAS
command file
vallabfile(none) do not save value labels
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fdause_options description
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clear replace data in memory
novallabels ignore accompanying formats.xpf file if it
exists
member(mbrname) member to use; seldom used
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Menu
fdasave
File > Export > FDA data (SAS XPORT)
fdause
File > Import > FDA data (SAS XPORT)
Description
fdasave, fdause, and fdadescribe convert datasets to and from the U.S.
Food & Drug Administration (FDA) format for new drug and new device
applications (NDAs) -- SAS XPORT Transport format. The primary intent of
these commands is to assist people making submissions to the FDA, but the
commands are general enough for use in transferring data between SAS and
Stata.
To save the data in memory in the FDA format, type
. fdasave filename
although sometimes you will want to type
. fdasave filename, rename
It never hurts to specify the rename option. In any case, Stata will
create filename.xpt as an XPORT file containing the data and, if needed,
will also create formats.xpf -- an additional XPORT file -- containing
the value-label definitions. These files can be easily read into SAS.
To read a SAS XPORT Transport file into Stata, type
. fdause filename
Stata will read into memory the XPORT file filename.xpt containing the
data and, if available, will also read the value-label definitions stored
in formats.xpf or FORMATS.xpf.
fdadescribe describes the contents of a SAS XPORT Transport file. The
display is similar to that produced by describe, as is the syntax:
. fdadescribe filename
If filename is specified without an extension, .xpt is assumed.
Options for fdasave
+------+
----+ Main +-------------------------------------------------------------
rename specifies that fdasave may rename variables and value labels to
meet the SAS XPORT restrictions, which are that names be no more than
eight characters long and that there be no distinction between
uppercase and lowercase letters.
We recommend specifying the rename option. If this option is
specified, any name violating the restrictions is changed to a
different but related name in the file. The name changes are listed.
The new names are used only in the file; the names of the variables
and value labels in memory remain unchanged.
If rename is not specified and one or more names violate the XPORT
restrictions, an error message will be issued and no file will be
saved. The alternative to the rename option is that you can rename
variables yourself with the rename command:
. rename mylongvariablename myname
See [D] rename. Renaming value labels yourself is more difficult.
The easiest way to rename value labels is to use label save, edit the
resulting file to change the name, execute the file by using do, and
reassign the new value label to the appropriate variables by using
label values:
. label save mylongvaluelabel using myfile.do
. doedit myfile.do (change mylongvaluelabel to, say, mlvlab)
. do myfile.do
. label values myvar mlvlab
See [D] label and [R] do for more information about renaming value
labels.
replace permits fdasave to overwrite existing filename.xpt, formats.xpf,
and filename.sas files.
vallabfile(xpf|sascode|both|none) specifies whether and how value labels
are to be stored. SAS XPORT Transport files do not really have value
labels. In preparing datasets for submission to the FDA, value-label
definitions should be provided in one of two ways:
1. In an additional SAS XPORT Transport file whose data contain the
value-label definitions
2. In a SAS command file that will create the value labels
fdasave can create either or both of these files.
vallabfile(xpf), the default, specifies that value labels be written
into a separate SAS XPORT Transport file named formats.xpf. Thus
fdasave creates two files: filename.xpt, containing the data, and
formats.xpf, containing the value labels. No formats.xpf file is
created if there are no value labels.
SAS users can easily use the resulting .xpt and .xpf XPORT files.
See http://www.sas.com/govedu/fda/macro.html for SAS-provided macros
for reading the XPORT files. The SAS macro fromexp() reads the XPORT
files into SAS. The SAS macro toexp() creates XPORT files. When
obtaining the macros, remember to save the macros at SAS's web page
as a plain-text file and to remove the examples at the bottom.
If the SAS macro file is saved as C:\project\macros.mac and the files
mydat.xpt and formats.xpf created by fdasave are in C:\project\, the
following SAS commands would create the corresponding SAS dataset and
format library and list the data:
+------------------- SAS commands --------------------+
| %include "C:\project\macros.mac" ; |
| %fromexp(C:\project, C:\project) ; |
| libname library 'C:\project' ; |
| data _null_ ; set library.mydat ; put _all_ ; run ; |
| proc print data = library.mydat ; |
| quit ; |
+-----------------------------------------------------+
vallabfile(sascode) specifies that the value labels be written into a
SAS command file, filename.sas, containing SAS proc format and
related commands. Thus fdasave creates two files: filename.xpt,
containing the data, and filename.sas, containing the value labels.
SAS users may wish to edit the resulting filename.sas file to change
the "libname datapath" and "libname xptfile xport" lines at the top
to correspond with the location that they desire. fdasave sets the
location to the current working directory at the time fdasave was
issued. No .sas file will be created if there are no value labels.
vallabfile(both) specifies that both the actions described above be
taken and that three files be created: filename.xpt, containing the
data; formats.xpf, containing the value labels in XPORT format; and
filename.sas, containing the value labels in SAS command-file format.
vallabfile(none) specifies that value-label definitions not be saved.
Only one file is created: filename.xpt, which contains the data.
Options for fdause
clear permits the data to be loaded, even if there is a dataset already
in memory and even if that dataset has changed since the data were
last saved.
novallabels specifies that value-label definitions stored in formats.xpf
or FORMATS.xpf not be looked for or loaded. By default, if variables
are labeled in filename.xpt, then fdause looks for formats.xpf to
obtain and load the value-label definitions. If the file is not
found, Stata looks for FORMATS.xpf. If that file is not found, a
warning message is issued.
fdause can use only a formats.xpf or FORMATS.xpf file to obtain
value-label definitions. fdause cannot understand value-label
definitions from a SAS command file.
member(mbrname) is a rarely specified option indicating which member of
the .xpt file is to be loaded. It is not used much anymore, but the
original XPORT definition allowed multiple datasets to be placed in
one file. The member() option allows you to read these old files.
You can obtain a list of member names using fdadescribe. If member()
is not specified -- and it usually is not -- fdause reads the first
(and usually only) member.
Option for fdadescribe
member(mbrname) is a rarely specified option indicating which member of
the .xpt file is to be described. See the description of member()
option for fdause directly above. If member() is not specified, all
members are described, one after the other. It is rare for an XPORT
file to have more than one member.
Remarks
SAS XPORT Transport format has been adopted by the U.S. Food & Drug
Administration (FDA) for datasets submitted in support of new drug and
device applications. For the FDA submission guidance document, see
http://www.fda.gov/cder/guidance/2867fnl.pdf.
All users, of course, may use these commands to transfer data between SAS
and Stata, but there are limitations in the SAS XPORT Transport format,
such as the eight-character limit on the names of variables (specifying
fdasave's rename option works around that). For a complete listing of
limitations and issues concerning the SAS XPORT Transport format, and an
explanation of how fdasave and fdause work around these limitations, see
the technical appendix in [D] fdasave. For non-FDA applications, you may
find it more convenient to use translation packages such as
Stat/Transfer; see http://www.stata.com/products/transfer.html.
Remarks are presented under the following headings:
Saving XPORT files for transferring to SAS
Determining contents of XPORT files received from SAS
Using XPORT files received from SAS
Saving XPORT files for transferring to SAS
To save the current dataset in clindata.xpt and the value labels in
formats.xpf, type
. fdasave clindata
To save the data as above but automatically handle renaming variable
names and value labels that are too long or are case sensitive, type
. fdasave clindata, rename
To allow the replacement of any preexisting files, type
. fdasave clindata, rename replace
To save the current dataset in clindata.xpt and the value labels in SAS
command file clindata.sas and to automatically handle renaming variable
and value-label names:
. fdasave clindata, rename vallab(sas)
To save the data as above but save the value labels in both formats.xpf
and clindata.sas, type
. fdasave clindata, rename vallab(both)
To not save the value labels at all, thus creating only clindata.xpt,
type
. fdasave clindata, rename vallab(none)
Determining contents of XPORT files received from SAS
To determine the contents of drugdata.xpt, you might type
. fdadescribe drugdata
Using XPORT files received from SAS
To read data from drugdata.xpt and obtain value labels from formats.xpf
(or FORMATS.xpf), if the file exists, you would type
. fdause drugdata
To read the data as above and discard any data in memory, type
. fdause drugdata, clear
Saved results
fdadescribe saves the following in r():
Scalars
r(N) number of observations
r(k) number of variables
r(size) size of data
r(n_members) number of members
Macros
r(members) names of members
Also see
Manual: [D] fdasave
Help: [D] describe, [D] infiling, [D] odbc, [D] outfile, [D] save
