dwelden wrote: > I have successfully used the sort lambda construct described in > http://mail.python.org/pipermail/python-list/2006-April/377443.html. > However, how do I take it one step further such that some values can be > sorted ascending and others descending? Easy enough if the sort values > are numeric (just negate the value), but what about text? > > Is the only option to define an external sorting function to loop > through the list and perform the comparisons one value at a time?
The simplest way is to take advantage of sort-stability and do successive sorts. For example, to sort by a primary key ascending and a secondary key decending: L.sort(key=lambda r: r.secondary, reverse=True) L.sort(key=lambda r: r.primary) A less general technique is to transform fields in a way that reverses their comparison order: L.sort(key=lambda r: (-r.age, r.height)) # sorts descending age and ascending height Raymond -- http://mail.python.org/mailman/listinfo/python-list
