Parentheses pairing ({}[]()<>) issue

Question

I want to be able to pair up all parentheses in a string, if they aren\'t paired then then they get their index number and False. It seems like it is repeating some values over

Answer 1

An understandable solution in Python 3:

def check_balanced_string(str):
  stack = []
  dicc = {'(': ')', '[': ']', '{': '}'}
  for char in str:
    if char in dicc.keys():  # opening char
      stack.append(char)
    elif char in dicc.values():  # closing char
      if dicc[stack[-1]] == char:  # check if closing char corresponds to last opening char
        stack.pop()
      else:
        return False
  return not len(stack)  # returns True when len == 0

eq = '{1+[3*5+(2+1)]}'
print(check_balanced_string(eq))