Re: st: Need help with regular expression

[Nick Cox <njcoxstata@gmail.com>]

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.
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