Find key of value

Finds the first key in the provided dictionary that has the given value.

  • Use dictionary.items() and next() to return the first key that has a value equal to val.
def find_key(dict, val):
  return next(key for key, value in dict.items() if value == val)
ages = {
  'Peter': 10,
  'Isabel': 11,
  'Anna': 9,
find_key(ages, 11) # 'Isabel'