You are correct about the -split- command (not option).
It doesn't do what you want, because the tools for
what you want had been in official Stata for a long
time before -split- was a gleam in anybody's eye.
And -index()-, -substr()- and -length()- will do what you want.
As I understand it, you want, for example, the three
digits before the "-" to be variable 3. You
just need to work through the steps.
Where is the "-"?
index(original, "-")
Where is 3 characters before that?
index(original,"-") - 3
How much do you want to extract?
3 characters
So
gen var4 = substr(original,index(original,"-")-3,3)
You can test this with an example:
di substr("9002346-A",index("9002346-A","-")-3, 3)
In fact, it seems that you want just
substr(original,-5,3)
where -5 means "count 5 backwards from the end".
Similarly var4 looks like substr(original,-1,1)
and var1 looks like
substr(original,1,length(original)-8)
In addition to the manuals there was some discussion
in
On getting functions to do the work. Stata Journal
2(4):411--427 (2002)
Nick
[email protected]
Julia A. Gamas
> I have an alfanumeric (string variable) such as 9002346-A or
> 15120657-4. I
> need to split this up into groups of smaller digits as follows:
>
> Original variable 1 variable 2 variable 3
> variable 4
> 9002346-A 9 002 346
> A
> 15120657-4 15 120 657
> 4
>
> The split option seems to only allow me to do this if there
> are spaces (or
> other markers, such as commas) within that variable, ie. 9
> 002 346-A or
> 9,002,346-A, which is not my case).
> I can't find an option within "strfun" which may help unless I've
> misunderstood the instructions for "char(n)" and "index".
> Also, note that 9 and 15 are different in size, adding a bit
> of complication
> to the issue.
> What I want to do can be done in excel (for smaller files) using
> "left(variable location, number of characters)" and "right"
> functions. Does
> anybody know if Stata has functions akin to "left" and
> "right" from excel?
> I can't seem to find any on the online help or stata archives.
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