st: RE: subinstr and special characters ? and *

["Nick Cox" <n.j.cox@durham.ac.uk>]

-subinstr()- is very literally-minded. It will not recognise wildcards
or regular expressions. You should consider using regex machinery. 

[D]     functions . . . . . . . . . . . . . . . . . . regexm() string
function
        (help regexm())

[D]     functions . . . . . . . . . . . . . . . . . . regexr() string
function
        (help regexr())

[D]     functions . . . . . . . . . . . . . . . . . . regexs() string
function
        (help regexs())

FAQ     . . . . . . . . . . . . . . . . . . . . . . . . .  Regular
expressions
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K. S.
Turner
        10/05   What are regular expressions and how can I use
                them in Stata?
                http://www.stata.com/support/faqs/data/regex.html

FAQ     . How to extract a portion of a string var. using regular
expressions?
        . . . . . . . . . . . . . . . . . .  UCLA Academic Technology
Services
        7/08    http://www.ats.ucla.edu/stat/stata/faq/regex.htm

Nick 
n.j.cox@durham.ac.uk 

A Loumiotis

Is there a way to use subinstr to replace a pattern that is given with
the special characters ? or * with something else?

For example:

local a p_2_3456
local b: subinstr local a "_?_" "__"
di "`b'"
local b=subinstr("`a'","_?_","__",1)
di "`b'"

I would expect that b will now be p__3456 but subinstr does not
recognize _?_ to include _2_ .
Is there anyway to do this?

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