On Wed, 22 Jul 2015 15:54:06 -0700, Robert Davis wrote: > Given a set of arrays within an array how do I find the arrays with the > minimum values based on two elements/columns in the array? Those two > elements/columns are the destination zip code and distance.
create a new dictionary for each source/destination pair in your list of source destination pairs: if the destination zip code is not in the new dictionary, copy the entry to the new dictionary keyed on the destination zip code. if the destination zip code is in the new dictionary, copy the entry to the new dictionary keyed on the destination zip code only if the distance is less than the distance of the current entry in the new dictionary. convert the values of the new dictionary to a list. write the list as csv Here is an example, note that I'm just using 2 bits of data, the first bit of data in each sub list simulates the destination area code, and the second simulates the distance from the associated source zip code. Obviously you need to adjust these to match the actual parameters in your list of lists. import csv info = [['a',15],['a',17],['a',21],['b',96],['b',45],['b',38],['c',71], ['c',18],['c',54]] tmp = {} for thing in info: if thing[0] in tmp: if thing[1] < tmp[thing[0]][1]: tmp[thing[0]] = thing else: tmp[thing[0]] = thing with open("output.csv", "wb") as f: writer = csv.writer(f) writer.writerows(tmp.values()) and lo: $ cat output.csv a,15 c,18 b,38 $ -- Denis McMahon, denismfmcma...@gmail.com -- https://mail.python.org/mailman/listinfo/python-list