Thanks Nick.
When I wrote the same command
by id : gen prev = city[1]
list prev city if prev != city & _n == 2
it gave me the the solution.
If I use "by id" again with the second command it would not list what I want.
Thanks,
Rijo.
On Fri, Nov 21, 2008 at 11:35 AM, Rijo John <[email protected]> wrote:
> Hi Nick,
>
> I will read more into the tip you gave.. When I gave the command you suggested
>
> by id : gen prev = city[1]
> by id : list prev city if prev != city & _n == 2
>
> it just lists all the ids... one by one... Doesn't solve the problem.
>
> Thanks.
> Rijo.
>
>
>
> On Fri, Nov 21, 2008 at 11:26 AM, Nick Cox <[email protected]> wrote:
>> This synthetic example shows that the command will list precisely those
>> observations that differ from the previous observation. But this
>> includes the first, as city[0] evaluates to string missing, i.e. "".
>> More generally, varname[0] is regarded as missing in the sense of the
>> variable's data type, i.e. numeric missing . or string missing "". So
>> the first in each group will always be listed (unless its value is
>> missing).
>>
>> . l
>>
>> +------------+
>> | city |
>> |------------|
>> 1. | Durham, UK |
>> 2. | Durham, UK |
>> 3. | Durham, UK |
>> 4. | Durham, NC |
>> 5. | Durham, NC |
>> |------------|
>> 6. | Durham, NH |
>> 7. | Durham, NH |
>> 8. | Durham, NH |
>> 9. | Durham, NH |
>> 10. | Durham, NH |
>> +------------+
>>
>> . list if city != city[_n-1]
>>
>> +------------+
>> | city |
>> |------------|
>> 1. | Durham, UK |
>> 4. | Durham, NC |
>> 6. | Durham, NH |
>> +------------+
>>
>> You probably want
>>
>> by id : gen prev = city[1]
>> by id : list prev city if prev != city & _n == 2
>>
>> There is no royal road to cleaning up string variables. The matter was
>> discussed on the list earlier this year and written up as a Tip:
>>
>> SJ-8-3 dm0039 . . . Stata tip 64: Cleaning up user-entered string
>> variables
>> . . . . . . . . . . . . . . . . . . . . . . . . J. Herrin and
>> E. Poen
>> Q3/08 SJ 8(3):444--445 (no
>> commands)
>> tip on how to clean up user-entered string variables
>>
>> Nick
>> [email protected]
>>
>> Rijo John
>>
>> I have a data set as follows
>>
>> ID City Year
>> 1 City name 1
>> 1 City name 2
>>
>>
>> The data is suppose to have same city names for each ids for year 1
>> and two. but there are many occasions where city for the year 1 is
>> spelt differently thanthat for year 2. I just want to list out or edit
>> those cities where city names are different for year 1 and 2 for the
>> same ID. When I issue the following command
>>
>> bysort ID : list if City!=City[_n-1]
>>
>> it lists all observations in the data whether or not the city is spelt
>> differently in years one and two. Thats strange to me? Can someone
>> tell what I am doing wrong here?
>>
>>
>> *
>> * 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/
>>
>
>
*
* 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/
