Question

I am working on a function. If “source” is found in “d” then it will be added to it’s value of dictionary object, otherwise it will be added. For example in this case. “a” is added twice but “b” is added once.

I would like to get output as below(last line)

Thank you.

def adder(source,dest,weight):
   """"""


if __name__ == "__main__":
  d = {} #dictionary
  adder('a','b',1)
  adder('a','f',4)
  adder('b','c',1)
  adder('f','g',3)

  print d

  {'a':{'b':1,'f':4}, 'b':{'c':1}, 'f':{'g':3},g:{},c:{}} #<----final o/p needed

Answer 1

The following implementation should do so:

def adder(dict, source, dest, weight):
   if not source in dict:
     dict[source] = {}
   if not dest in dict:
     dict[dest] = {}
   dict[source][dest] = weight

Please note that I added dict as first argument to your method.