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Question

Im trying to create a function increase_by_one which takes in a dictionary and modifies the dictionary by increasing all values in it by 1. The function should remain all keys unchanged and finally return the modified dictionary. If the dictionary is empty, return it without changing. (Dictionaries can be nested)

eg

increase_by_one({'1':2.7, '11':16, '111':{'a':5, 't':8}})

would give

{'1': 3.7, '11': 17, '111': {'a': 6, 't': 9}}

Im not sure how to do it for multiple(and unknown of number) nested dicitionaries. Thank you. Would prefer the code to be as simple as possible

Answer 1

This is a simple way to solve the problem using recursion and dict comprehension:

def increase_by_one(d):
    try:
        return d + 1
    except:
        return {k: increase_by_one(v) for k, v in d.items()}

In case there are values contained in the dict apart from numbers which can be added or other dictionaries, further type checking might be necessary.

Answer 2

Assuming the values are either a number or a dictionary, you could consider:

def increase_by_one(d):
  for key in d:
    if type(d[key])==dict:
      d[key] = increase_by_one(d[key])
    else:
      d[key] += 1
  return d

For you input:

print(increase_by_one({'1':2.7, '11':16, '111':{'a':5, 't':8}}))

I got:

{'1': 3.7, '11': 17, '111': {'a': 6, 't': 9}}

Answer 3

def increase_by_one(d):
  for key in d:
    try:
      d[key] += 1
    except:  # cannot increase, so it's not a number
      increase_by_one(d[key])
  return d  # only necessary because of spec

Answer 4

def increase_by_one(dictio):
    for d in dictio:
        if isinstance(dictio[d], int) or isinstance(dictio[d], float):
            dictio[d] += 1
        else:
            increase_by_one(dictio[d])
    return dictio

increase_by_one({'1':2.7, '11':16, '111':{'a':5, 't':8}})

Using recurrence

Answer 5

In-place modification of dict:

def increase_by_one(my_dict):
    for k, v in my_dict.items():
        if any(isinstance(v, x) for x in (float, int)):
            my_dict.update({k: v + 1})
        elif isinstance(v, dict):
            my_dict.update({k: increase_by_one(v)})
    return my_dict

v = {'1': 2.7, '11': 16, '111': {'a': 5, 't': 8}}
print(increase_by_one(v))  # prints: {'111': {'a': 6, 't': 9}, '1': 3.7, '11': 17}