Python TypeError: 'type' object does not support item assignment -

i have design , implement twosum class. should support following operations:

• add - add number internal data structure.
• find - find if there exists pair of numbers sum equal value.

here code:

class twosum(object):      dict = {}      def add(self,n):         dict[n] = n #typeerror: 'type' object not support item assignment      def find(self,n):         in range(0,len(dict)+1):             if dict[i] == none:                 continue              val = n - dict[i]             if dict[val] != none , val != i+1:                 return true         return false  test = twosum() test.add(1) test.add(3) test.add(5) print(test.find(4))  # true print(test.find(7))  # false 

i got error message

typeerror: 'type' object not support item assignment "dict[n] = n"

any or suggestion? thank much!

lot of issues here, i'll try go through them 1 one

the data structure

dict = {} 

not overwriting python's dict, (see mgilson's comment) wrong data structure project. should use list instead (or set if have unique unordered values)

using data structure

the data structure instance variable, needs defined self , inside __init__ function. should using this:

class twosum(object):     def __init__(self):         self.numbers = [] 

def add

def add(self,n):         dict[n] = n 

assigning items dictionairy not way it. should instead append list. additionally need append list instance using self.variablename = value

def find

that range wrong, , need nested range, or itertools.combinations since have check 2 numbers sum value, pythons sum() handy here.

to loop through numbers can use 2 ranges or itertools.combinations

the code

import itertools  class twosum(object):     def __init__(self):         self.numbers = []      def add(self, num):         self.numbers.append(num)      def find(self, desiredsum):         nums in itertools.combinations(self.numbers, 2):             if sum(nums) == desiredsum:                 return true         return false   test = twosum() test.add(1) test.add(3) test.add(5) print(test.find(4)) print(test.find(7)) #true #false 

def find without itertools

def find(self, desiredsum):         num1 in self.numbers:             num2 in self.numbers:                 if num1 + num2 == desiredsum , num1 != num2:                     return true         return false