Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: st: Generating variable that counts number of appearances
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: Generating variable that counts number of appearances
Date
Sun, 1 Apr 2012 09:14:22 +0100
This is just to underline that the help for -countmatch- explains how
to do this.
On Sat, Mar 31, 2012 at 9:55 AM, Nick Cox <[email protected]> wrote:
> Use
>
> . ssc desc countmatch
>
> in a loop across friend variables.
>
> Nick
>
> On Sat, Mar 31, 2012 at 6:29 AM, Timothy Malacarne
> <[email protected]> wrote:
>> Hello,
>>
>> I'm attempting to create a variable the counts the number of times a unique id value for existing variable 1 appears across all observations variable two. In this case, individuals have unique IDs. They are then asked to name their friends, who appear by their id number in a series of friend variables. Each value is unique in the "ID" variable, but 3 people might nominate the same ID value under the Friend variable. I want to count up how often each individual is named a friend by others.
>>
>> To do so, I wrote this code:
>>
>> gen NumberFriends=.;
>>
>> forval k = 90316050/99798989 {; *the range of ID values
>> egen tot`k' = total(Friend1ID==`k');
>> replace NumberFriends=tot`k' if `k'==ID;
>> drop toad`k';
>> };
>>
>> Unfortunately, it needs to loop over all values in the ID range for it to work and I don't have the computational power to do this in a reasonable amount of time. Is there a computationally more efficient way to count up ID cross references in Stata?
>>
*
* 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/