merge(HashTable,HashTable,Function) -- merge hash tables

Synopsis

• Usage:

  z = merge(x,y,g)

• Function: merge
• Inputs:

  • x, a hash table
  • y, a hash table
  • g, a function, a function of two variables to be used to combine a value of x with a value of y when the corresponding keys coincide.
• Outputs:

  • z, a hash table, a new hash table whose keys are the keys occurring in x or in y; the same values are used, except that if if a key k occurs in both arguments, then g(x#k,y#k) is used instead, unless g evaluated continue, in which case the key k does not appear in the result.

Description

i1 : Free = new Type of HashTable

o1 = Free

o1 : Type

i2 : p = new Free from { "x" => 2, "y" => 3, "cat" => 5 }

o2 = Free{cat => 5}
          x => 2
          y => 3

o2 : Free

i3 : q = new Free from { "x" => 100, "y" => 200, "dog" => 7 }

o3 = Free{dog => 7}
          x => 100
          y => 200

o3 : Free

i4 : Free + Free := (p,q) -> merge(p,q,plus);

i5 : p+q

o5 = Free{cat => 5}
          dog => 7
          x => 102
          y => 203

o5 : Free

See also

• combine -- combine hash tables