/ package:base

Fractional division.

Constructs an array identical to the first argument except that it has been updated by the associations in the right argument. For example, if m is a 1-origin, n by n matrix, then

m//[((i,i), 0) | i <- [1..n]]

is the same matrix, except with the diagonal zeroed. Repeated indices in the association list are handled as for array: Haskell 2010 specifies that the resulting array is undefined (i.e. bottom), but GHC's implementation uses the last association for each index.