Sure, for a dataframe that looks like this ID Year Value 1 2012 100 1 2013 102 1 2014 106 2 2012 110 2 2013 118 2 2014 128
I'd like to get back ID Year Value 1 2013 2 1 2014 4 2 2013 8 2 2014 10 i.e the Value for an ID,Year combination is the Value for the ID,Year minus the Value for the ID,Year-1 thanks On 10 January 2016 at 20:51, Femi Anthony <femib...@gmail.com> wrote: > Can you clarify what you mean with an actual example ? > > For example, if your data frame looks like this: > > ID Year Value > 1 2012 100 > 2 2013 101 > 3 2014 102 > > What's your desired output ? > > Femi > > > On Sat, Jan 9, 2016 at 4:55 PM, Franc Carter <franc.car...@gmail.com> > wrote: > >> >> Hi, >> >> I have a DataFrame with the columns >> >> ID,Year,Value >> >> I'd like to create a new Column that is Value2-Value1 where the >> corresponding Year2=Year-1 >> >> At the moment I am creating a new DataFrame with renamed columns and >> doing >> >> DF.join(DF2, . . . .) >> >> This looks cumbersome to me, is there abtter way ? >> >> thanks >> >> >> -- >> Franc >> > > > > -- > http://www.femibyte.com/twiki5/bin/view/Tech/ > http://www.nextmatrix.com > "Great spirits have always encountered violent opposition from mediocre > minds." - Albert Einstein. > -- Franc
