selectValues -- select part of a hash table by values

• Usage:

  selectValues(v,f)

  selectValues(n,v,f)

• Inputs:
  • n, an integer
  • v, a hash table
  • f, returning either true or false
• Outputs:
  • whose pairs are those key-value pairs (k,w) of the hash table v that yield true when the function f is applied to the value w.If n is provided, at most n pairs will be selected.

i1 : x = new HashTable from { x => 1, y => 2, z => 3 }

o1 = HashTable{x => 1}
               y => 2
               z => 3

o1 : HashTable

i2 : select(x,odd)

o2 = HashTable{x => 1}
               z => 3

o2 : HashTable

i3 : select(1,x,odd)

o3 = HashTable{x => 1}

o3 : HashTable