*! version 1.1.1 23Jan2019

Title

gisid -- Efficiently check for unique identifiers using C plugins.

Important: Please run gtools, upgrade to update gtools to
the latest stable version.

Syntax

This is a fast option to Stata's isid.
It is 8 to 30 times faster in Stata/IC and 4-14 times faster in MP

gisid
varlist
[if] [in]
[,
missok]

Description

gisid is a faster alternative to isid. It can check for an ID in
a subset of the data, but it can't do it for an external dataset or sort the data.

gisid is part of the [R] gtools project.

Options

missok indicates that missing values are permitted in varlist.

Gtools

compress Try to compress strL to str#. The Stata Plugin Interface
has only limited support for strL variables. In Stata 13 and earlier
(version 2.0) there is no support, and in Stata 14 and later (version
3.0) there is read-only support. The user can try to compress strL
variables using this option.

forcestrl Skip binary variable check and force gtools to read strL
variables (14 and above only). Gtools gives incorrect results when there is binary data in strL variables.
This option was included because on some windows systems Stata detects
binary data even when there is none. Only use this option if you are
sure you do not have binary data in your strL variables.

verbose prints some useful debugging info to the console.

benchmark and benchmarklevel(int) print how long in
seconds various parts of the program take to execute. The user can also
pass bench(int) for finer control. bench(1) is the same
as benchmark but bench(2) and bench(3) additionally print
benchmarks for internal plugin steps.

hashmethod(str) Hash method to use. default automagically
chooses the algorithm. biject tries to biject the inputs into the
natural numbers. spooky hashes the data and then uses the hash.

oncollision(str) How to handle collisions. A collision should never
happen but just in case it does gtools will try to use native commands.
The user can specify it throw an error instead by passing oncollision(error).

Examples

See isid or the
online documentation
for examples.

Author

Mauricio Caceres Bravo

mauricio.caceres.bravo@gmail.com

mcaceresb.github.io

Website

gisid is maintained as part of [R] gtools at github.com/mcaceresb/stata-gtools

Acknowledgment

This help file was based on StataCorp's own help file
for isid and Sergio Correia's help file for fisid.

This project was largely inspired by Sergio Correia's ftools:
https://github.com/sergiocorreia/ftools.

The OSX version of gtools was implemented with invaluable help from @fbelotti;
see https://github.com/mcaceresb/stata-gtools/issues/11.

Also see

help for
gisid,
gtools;
fisid (if installed),
ftools (if installed)