13 Dec
2016
13 Dec
'16
10:23 a.m.
On Tue, Dec 13, 2016 at 02:36:39PM +0000, mike h wrote:
Hi,
I’m trying to sort a list of tuples. A char and a count of that char (Char , Int) e.g.
[ ('r',2), ('c',2),('a', 2), ('b',3), ('f',2)]
e.g. ‘r’ occurs twice etc. The order should be based on the count first and then ties broken by the natural ordering of char.
You should provide sortBy with an appropriate compare function, e.g. comp (a,b) (c,d) | a > c = GT | -- etc etc. or go with the manky but working hack: λ> :m Data.List λ> sortOn (\(a, b) -> b*(-100) + fromEnum a) [('r',2), ('c',2),('a', 2), ('b',3), ('f',2)] [('b',3),('a',2),('c',2),('f',2),('r',2)]