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Re: -merge- (?) problem (was: st: MIME-Version: 1.0)


From   "Eva Poen" <eva.poen@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: -merge- (?) problem (was: st: MIME-Version: 1.0)
Date   Tue, 30 Sep 2008 10:08:51 +0100

As Martin said, there are tools out there to do this.

However, if you are generally interested in parallel lists:
There is an faq on how to process parallel lists:
http://www.stata.com/support/faqs/lang/parallel.html

Also, Nick Cox wrote a Stata Tip on lists, which is available free of
charge thanks to the moving wall policy by StataCorp:
http://www.stata-journal.com/article.html?article=pr0009

Eva


2008/9/30 Ashim Kapoor <ashimkapoor@gmail.com>:
> Hello.
>
> Thank you for your reply. I wish to ask another ( related ) question.
>
> Suppose I have 2 local variables with the SAME no of "words".
>
> local name="One Two Three Four"
> local numname="one two three four"
>
> I want to do something like :-
>
> rename One one
> rename Two two
> rename Three three
> rename Four four.
>
> So I have 2 questions. How do I get the number of words in the local
> macro. And 2nd How do I access the 1/2/3/4 "word" of the macro. I have
> seen the word command for STRING variables, but can I do this for a
> local variable ?
>
> Thank you,
> Ashim.
>
>
> On Mon, Sep 29, 2008 at 9:03 PM, Eva Poen <eva.poen@gmail.com> wrote:
>> Ashim,
>>
>> Please try and use Stata lingo in your postings: observations (not
>> rows, or items) and variables (not columns).
>>
>> You can do it much easier. -help merge- will provide some good information.
>>
>> ***
>> use secondfile
>> sort symbol year
>> save, replace
>>
>> use firstfile
>> sort symbol
>> merge symbol using secondfile, uniqmaster
>> save mergefile
>> ***
>>
>> Now you will have ticker as a variable in you second file. Inspect the
>> _merge variable (see -help merge-) to make sure the outcome is what
>> you expected.
>>
>> Next:
>> ***
>> qui levelsof symbol, local(loop)
>> foreach x of local loop {
>> drop _all
>> use mergefile
>> keep if symbol == "`x'"
>> save `=ticker[1]'
>> }
>> ***
>>
>> HTH,
>> Eva
>>
>> 2008/9/29 Ashim Kapoor <ashimkapoor@gmail.com>:
>>> Hello Eva,
>>>
>>> Thank you for your time. Let me be more clear this time.
>>>
>>> In the first file I have 2 variables--> symbol and ticker. The tickers
>>> are file names I want to save various output files as.  There is a one
>>> one correspondence between symbol and tickers. For example.
>>>
>>>     symbol    ticker
>>> 1.    ABB       abb
>>> 2.    BHARTI  bti
>>> 3.    AIRTEL   artl
>>>
>>>
>>> That is what the first file looks like.
>>>
>>> the second file has variables year / symbol / production / etc.
>>>
>>> It looks like
>>>
>>>   symbol              year    production
>>> 1.   ABB              1998          92
>>> 2.   ABB              1999          95
>>> 3.   BHARTI          1998          61
>>> 4.   BHARTI           1999         70
>>> 5.   AIRTEL           2000          80
>>> 6.  AIRTEL            2001          81
>>>
>>> Now I want to save items 1 and 2. ie. items with symbol = ABB in a
>>> file named "abb.dta"
>>> I want to saves items 3 & 4 ie. items with symbol= BHARTI in a file
>>> named "bti.dta"
>>> and items with symbol = "AIRTEL" in a file named "artl.dta".
>>>
>>> So I guess this would be a 2 step procedure.
>>>
>>> Step 1 : store all symbols in ONE local macro and store all tickers in
>>> the 2nd local macro.
>>>
>>> Step 2 : Loop through the 2 equal sized loops, do a keep if symbol ==
>>> ...... and save as the corresponding ticker .
>>>
>>> Can u tell me how to do this in stata ?
>>>
>>> Thank you,
>>> Ashim.
>>>
>>> On Mon, Sep 29, 2008 at 4:38 PM, Eva Poen <eva.poen@gmail.com> wrote:
>>>> Ashim,
>>>>
>>>> I'm sorry but I don't get it. You have two variables in your first
>>>> file, called symbol and ticker. What are they? Numeric, string? In
>>>> your second file you have symbol again (what about ticker?), and many
>>>> more variables, and you also have more observations (symbol does no
>>>> longer uniquely identify observations).
>>>>
>>>> Now you want to do some operation that looks suspciously like a
>>>> -merge-, but it's unclear to me. For each symbol from file 1, you want
>>>> to -use- file 2 and -keep- all observations with this symbol.
>>>> Following what you said earlier, you will now be left with approx. 100
>>>> observations and many variables. Now you say you want to save this "as
>>>> ticker in the 1st file". What do you mean by that? You want to save
>>>> all 100 observations and many variables, in the first file? And what's
>>>> that to do with ticker? Ticker already exists in the first file. Do
>>>> you want to replace it, and with what information? Or do you want to
>>>> add ticker to the second file?
>>>>
>>>> You'll have to be more precise for someone to be able to help.
>>>>
>>>> Eva
>>>>
>>>> 2008/9/29 Ashim Kapoor <ashimkapoor@gmail.com>:
>>>>> Hello everyone,
>>>>>
>>>>> I have 2 files.
>>>>>
>>>>> The 1st file has 2 columns --> symbol and ticker. [ each symbol is
>>>>> only in one observation ]
>>>>>
>>>>> The 2nd file has many more columns --> symbol and many other vars. [
>>>>> each symbol is in around 100 observations here ]
>>>>>
>>>>> I want to say foreach symbol in 1st file  {
>>>>>
>>>>> use 2nd file
>>>>>
>>>>> keep if symbol ==above symbol
>>>>>
>>>>> save as ticker in the 1st file
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>> Can someone tell me how to do this ?
>>>>>
>>>>> I guess to start with I would have to save the entire observations in
>>>>> symbol var in 1st file in ONE local macro and similarly for the
>>>>> ticker. Can someone tell me how to do this ?
>>>>>
>>>>> Thank you,
>>>>>
>>>>> Ashim.
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