Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Need help with regular expression


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Need help with regular expression
Date   Sun, 17 Feb 2013 10:03:36 +0000

Alison's suggestion is surely right. If your condition is not
restrictive enough, you need to make it more restrictive.

If it is a separate word, it occurs surrounded by spaces or at the
beginning or end with one space after or before. I tend to build up
syntax using -display- and little examples.

. di regexm("us marines", "^us ")
1

. di regexm("show us", " us$")
1

. di regexm("invited us to dinner", " us ")
1

You could also use -strpos()-

... if strpos(var, " us ") | strpos(var, "us ") == 1 | strpos(var, " us") == -3

Note that -regexm()- is a function, not a command. in Stata functions
and commands are quite separate in definition and documentation.
-strpos()- is another function. Fixing _function_ firmly in mind as
the key term leads to consultation of the documentation on functions,
which as here can suggest alternatives.

There are also solutions with -word()- but they all seem to entail a loop.

Nick

On Sun, Feb 17, 2013 at 8:04 AM, Alison Connor

> I am sure there is a much better way to do this, but until someone who
> actually knows responds, could you try something like:
>
> regexm(var, " us ") | regexm(var, " us&") | regexm(var, "^us ")  ?

On Sun, Feb 17, 2013 at 1:00 PM, Michael Stewart

>> I am trying to use regexm command (regexm(var,"us"))to see if the
>> values of variable have a particular string "us" like in  "us thyroid"
>> .Unfortunately , it is picking up "us" from other string values like
>> "venous".If there a way to formulate command so that it can pick up
>> only values  where "us" is a separate word and not part of word like
>> venous.
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index