The last project on the python data structures course ( balanced parentheses )

Question

My code passed all test cases except for the last one (test case #7). What can I do to make it pass that case?

I have to output True if the parentheses are balanced and False otherwise. For example, "(1+2)×(-2)" is balanced, while "(12)×7)" is not balanced.

My code:

def balanced(expression):
#your code goes here
par = []
for i in expression:
if i == "(":
par.insert(0, i)
for i in expression:
if i == ")":
if len(par) != 0:
par.pop()
else:
return False
if len(par) != 0:
return False
else:
return True

print(balanced(input()))

Answer 1

As task description mentioned "7-(3(2*9))4) (1" is not balanced, although it has the same number of "(" and ")".

Answer 2

Wong Hei Ming ah... I understand... my code can't handle the case when ")" comes before "(", thank you! I'll try to debug it

Answer 3

Without seeing your code, there is no point in guessing what you might be doing wrong.
Maybe you forgot about an "edge case", a special scenario or strange kind of input.
If you explain the task, and link your code, maybe someone can review and find the error in your logic.