I have got the right output for three test cases but not for the rest what's the problem in the code!

Question

Parentheses are balanced, if all opening parentheses have their corresponding closing parentheses.

Given an expression as input, we need to find out whether the parentheses are balanced or not.
For example, "(x+y)*(z-2*(6))" is balanced, while "7-(3(2*9))4) (1" is not balanced.

The problem can be solved using a stack.
def pairs(open,close):
if open=='('and close==')':
return True
if open=='{'and close=='}':
return True
if open=='['and close==']':
return True
return False
def balanced(exp):
stack = []
for i in range (len(exp)):
if exp[i]=='('or exp[i]=='{'or exp[i]=='[':
stack.append(exp[i])
elif exp[i]==')'or exp[i]=='}'or exp[i]==']':
if pairs(stack[-1],exp[i]or len(stack)!=0):
stack.pop()
else:
return False
if len(stack)==0:
return True
else:
False
exp = input(" ")
print(balanced(exp))

Answer 1

# Hi! Is it possible to make a more simple solution; can this one help you? (You still need to modify it to fit your needs, of course.)

s = input()
b = 0
for i in s:
if i == "(":
b += 1
elif i == ")":
b -= 1
if b < 0:
msg_balance = "not"
break
else:
msg_balance = "not" if b else ""
print(msg_balance, "balanced")

# Why or why not?

https://code.sololearn.com/cpuSHXo64jsS/?ref=app

Answer 2

if pairs(stack[-1],exp[i]or len(stack)!=0):

I think you've messed up your brackets here. You're passing `exp[i] or len(stack)!=0` as the second argument to your pairs() function.

There's a bunch of other formatting issues there. Can you link to the code?