----------------------------- On Thu, May 14, 2015 3:35 PM CEST Dennis Lee Bieber wrote:
>On Wed, 13 May 2015 16:24:30 -0700, 20/20 Lab <l...@pacbell.net> declaimed >the following: > >>Now is were I have my problem: >> >>myList = [ [123, "XXX", "Item", "Qty", "Noise"], >> [72976, "YYY", "Item", "Qty", "Noise"], >> [123, "XXX" "ItemTypo", "Qty", "Noise"] ] >> >>Basically, I need to check for rows with duplicate accounts row[0] and >>staff (row[1]), and if so, remove that row, and add it's Qty to the >>original row. I really dont have a clue how to go about this. The >>number of rows change based on which run it is, so I couldnt even get >>away with using hundreds of compare loops. >> >>If someone could point me to some documentation on the functions I would >>need, or a tutorial it would be a great help. >> > > This appears to be a matter of algorithm development -- there won't be >an pre-made "function" for it. The closest would be the summing functions >(control break http://en.wikipedia.org/wiki/Control_break ) of a report >writer application. > > The short gist would be: > > SORT the data by the account field > Initialize sum using first record > loop > read next record > if end of data > output sum record > exit > if record is same account as sum > add quantity to sum > else > output sum record > reset sum to the new record > > Granted -- loading the data into an SQL capable database would make >this simple... > > select account, sum(quantity) from table > order by account You could also use pandas. Read the data in a DataFrame, create a groupby object, use the sum() and the first() methods. http://pandas.pydata.org/pandas-docs/version/0.15.2/groupby.html -- https://mail.python.org/mailman/listinfo/python-list
