Re: st: Drop under several conditions and time (year)

["Brill, Robert" <robertbrill@austin.utexas.edu>]

Sorry, that second to last line should be

drop if LongTermDebt2007>TotalAssets2007 | LongTermDebt2008>TotalAssets2008

 

On 3/23/14, 4:44 PM, "Brill, Robert" <robertbrill@austin.utexas.edu> wrote:

>Your -if- subsetting seems to be incorrect. Right now, your code says
>³drop if the year is equal to 2007, or, if the year is 2008 and long-term
>debt is greater than total assets.²
>
>What you intended to type was probably something more like:
>
>drop if (Year==2007 & LongTermDebt>TotalAssets) | (Year==2008 &
>LongTermDebt>TotalAssets)
>
>But that will only remove the rows for which those statements are true,
>not the entire firm.
>
>Stata does not know the format of your data, so it will not drop the
>entire firm, only the rows for which the -if- statement is true.
>
>For this reason, previous answers to your question have used the -egen-
>command to create a drop indicator, which will be one for all rows of a
>firm if the firm fulfills a certain condition.
>
>An easier way for you to understand your problem might be to reshape your
>data into ³wide² format, such that each row represents one firm, and has a
>variable for each variable for each year. Thus 13 rows of LongTermDebt are
>converted to thirteen columns of LongTermDebt named LongTermDebt2000,
>LongTermDebt2001, etc. You can do this by doing:
>
>reshape wide LongTermDebt TotalAssets, i(Firm) j(Year)
>
>drop if LongTermDebt2007>TotalAssets2007 |
>LongTermDebt2008>LongTermDebt2008
>
>reshape long
>
>Of course, if your data contain variables other than those you have
>described, you¹ll need to include them in the argument of reshape (before
>the comma). The advantage of reshaping your data to wide is that you will
>be able to drop observations on single row conditions, rather than trying
>to understand -egen-, which can be complicated for a novice to data
>management. 
>
>Regarding your other question, if you simply have a list of keys you want
>to drop, rather than encoding your string variable, you could simply use
>the correct syntax for strings:
>
>drop if Key==³C0056"
>
>Notice the quotation marks‹values of string variables must be enclosed in
>quotation marks for Stata to understand what to evaluate.
>
>
>
>
>
>
>
>
>On 3/23/14, 4:10 PM, "Julian Kochan" <julian.kochan@gmx.de> wrote:
>
>>Hi,
>>
>>i have a set of data with financial firm characteristics of about 10.000
>>firms for Year 2000 - Year 2012.
>>
>>Let's assume: The first column of the data table displays the Name of the
>>firm, the second the Year, the third displays the LongTerm Debt and the
>>fourth the TotalAssets.
>>Thus, 13 rows in a row (2000-2012) display information about just one
>>firm - just the year varies.
>>
>>Problem: I want to drop those firms, for which LongTermDebt is greater
>>than TotalAssets in the Year 2007 or Year 2008.
>>         If this is the case, the firm should be dropped out of my data
>>completely such that the firm observation is not only dropped for 2007
>>and 2008, but also for all the other years.
>>         
>>        I tried: drop if Year == 2007 | Year == 2008 & LongTermDebt >
>>TotalAssets. This made Stata to delete about 5000 observation altough I
>>just had 150 observations with LongTermDebt > Total Assets.
>>        There is something I do not get as a Stata beginner. Is the drop
>>function the wrong function when trying to delete observations under
>>several conditions such as comparing Debt to Assets ?
>>
>>I would be really really happy to receive an answer.
>>
>>Julian
>>*
>>*   For searches and help try:
>>*   http://www.stata.com/help.cgi?search
>>*   http://www.stata.com/support/faqs/resources/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/faqs/resources/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/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/