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Re: st: RE: problems with encode
"Lukas Bösch" <L.Boesch@gmx.de>
Re: st: RE: problems with encode
Wed, 01 Jun 2011 16:40:38 +0200
Thank you for your quick reply.
Unfortunately Stata does not accept the command you suggested.
If i enter:
destring y1990-y2009, replace dpcomma
option dpcomma not allowed
I am working with Stata10.0. Might this be a reason why this command does not work?
I looked through all the options given for the command -destring- in the Stata help before asking statalist. These are generate, replace, ignore, force, float, percent. I tried them, apart from ignore and force, but they don't work. They either create missings, or stata tells me:
contains nonnumeric characters; no generate/replace.
-------- Original-Nachricht --------
> Datum: Wed, 1 Jun 2011 11:08:46 +0100
> Von: Nick Cox <email@example.com>
> An: "\'firstname.lastname@example.org\'" <email@example.com>
> Betreff: st: RE: problems with encode
> As you have found out, -encode- will take values like "0,43" and map them
> to integers with value labels. They will look the same as before, but in
> principle the approach is quite wrong for such data.
> As you say, you need to -destring- such variables. What you need with your
> data is to spell out the -dpcomma- option.
> Note that with -destring- you can operate on several variables at once.
> . destring y1990-y2009, replace dpcomma
> All this is documented in the help for -destring-.
> Lukas Bösch
> I am having problems working with data that were stored as string
> variables and that i converted to numeric variables with encode. In this case the %
> of a countrys surface is sored as a string variable, (y1990-y2009) and i
> am encoding it into numeric variable (v1990-2009)
> here is one example:
> encode y1990, gen (v1990) I did this for 1990-2009 and 130 countries but
> only show the first two countries and the 4 first years.
> country y1990 y1991 y1992 y1993 v1990 v1991 v1992 v1993
> Afghan 0,43 0,43 0,43 0,43 0,43 0,43 0,43 0,43
> Algeria 6,31 6,31 6,31 6,31 6,31 6,31 6,31 6,31
> this seems to work fine, but when i am reshaping the data into a long
> form, it doesn't work any more.
> drop y1990-y2009:
> reshape long v, i(id) j(year);
> year country v
> 1990 Afghanistan 0,83
> 1991 Afghanistan 0,83
> 1992 Afghanistan 0,83
> 1993 Afghanistan 0,83
> 1990 Algeria 5,62
> 1991 Algeria 5,88
> 1992 Algeria 6,17
> 1993 Algeria 5,92
> reshaping the string variable works fine though.
> Another problem i am having with encoded data is the following:
> The human development index is measured all 5 years (1990, 1995, 2000,
> 2005, 2009). I have stored it as a string variable and want to have it for the
> whole time period (1990-2009). In order to do this i just copy the values
> for the next years. For example, the hdi of 1990 is copied into 1991, 1992,
> 1993 and 1994. Here again, i start with encoding the data.
> encode v1990, gen(value1990). I am doing this for all 5 years.
> country v1990 v1995 v2000 value1990 value1995 value2000
> Norway 0,838 0,869 0,906 0,838 0,869 0,906
> Austra 0,819 0,887 0,914 0,819 0,887 0,819
> the next step is to generate the missing years and to copy the value of
> the existing years.
> gen value1991 = value1990
> In this case, stata creates a ranking and doesn't copy the value.
> I am wondering how to deal with these problems. If i do these operations,
> the reshaping and copying, with the string variables, everything works
> fine, but i cant calculate with string variables and my aim is to do a
> regression model.
> I have read in the help file that, if the string variable contains numeric
> values simply stored as strings, which is my case, i should use the
> destring or generate real() functions.
> I tried those, but they dont work:
> destring v1990, replace
> stata says: v1990 contains nonnumeric characters; no replace
> and the same with destring, gen()
> in the case of generate value1990 = real(v1990)
> stata just generates missings.
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
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