Re: st: How blanks are treated when vars are read in as string froman ASCII raw data file

[Ian Watson <ian.watson@tpg.com.au>]

Clare

I've reproduced your problem and compared it with yesterday's solution 
and can only come up with one suggestion.

When you infile the string and then split it, using the substr function, 
the right hand component (which I called num in yesterday's post) has 
leading blanks on it. These are then replaced by leading 0s using the 
subinstr function.

However, when you infile the string as two strings, Stata possibly 
strips the leading blanks from it. Even though it has the designation of 
a str3 type, it may not have the same "contents" as num did (which was 
also a str3 type) because that latter was created from substr. That
is " 23" and "23" look the same on the screen, but they're not the same 
data.

This is only a guess, and I can't find an easy way to test it. But it 
suggests you're better off reading your string in as a full string, then 
splitting it, rather than as two strings. At least that works (even if 
the reason is not altogether clear to me why).

--
Kind regards,
Ian

-------------------------------
Ian Watson
Senior Researcher
acirrt, University of Sydney
NSW, 2006, Australia

phone: 02 9351 5622
email:i.watson@econ.usyd.edu.au
www.acirrt.com
-------------------------------




Clare L Maxwell wrote:

> Hello again to the Statlist writers.
>
> This is a reprise of a problem I asked about yesterday, involving a 
> 6-place string subject identifier that is read in from an ASCII file. In 
> the ASCII file, this is how the data look:
>
> B    1
> B  120
> CCH  7
> CCH 23
> CCH213
> UW  23
> UW 232
>
> I want to turn them into a variable that looks like this:
>
>   B001
>   B120
> CCH007
> CCH023
> CCH213
>  UW023
>  UW232
>
> I had two very helpful recommendations on how to accomplish this. 
> However, the results were not as hoped.
>
> I read the data into Stata as two str3 variables:
>
> infile dictionary using "/Projects/Christina/HNS/Stata/data/cm1.raw" {
>   str3       site         %3s
>   str3       siteid       %3s
> ...... many more vars
>   }
>
> I was surprised when they looked like this in Stata:
>
> site siteid
>    B      1
>    B    120
>  CCH      7
>  CCH     23
>  CCH    213
>   UW     23
>   UW    232
>
> In other words, now they both appeared as right justified once they had 
> been read in (siteid was that way before in the ASCII file).
>
> This saved me the trouble of manipulating site.  However, when I tried 
> to left pad siteid with zeros, as suggested by Ian Watson and Nick Cox:
>
> replace siteid = subinstr(siteid," ","0",.)
>
> I got the message that zero replacements have been made.  When I 
> concatenated the site and siteid to get my final ID variable, I got the 
> following:
>
>     B1
>   B120
>   CCH7
>  CCH23
> CCH213
>   UW23
>  UW232
>
> This is similar to problems I was having before my original letter. 
> There must be something I do not understand how blanks are treated in 
> string variables created this way.  In the ASCII file, these variables 
> are not enclosed in quotation marks to signify that they are string 
> variables.  I just say string and how long when they are read in.  I 
> later merge three files by these IDs plus dates, and in order to do 
> that, I have to compress the files.  I thought compression might have 
> been the problem.  Sadly, not compressing did not resolve this.  I also 
> just updated Stata.  No change.  Can anyone shed more light?
>
> Thank you very much for your help.
>
>                 Yours truly,
>                 Clare Maxwell
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