Python code to Check for balanced parentheses in an expression

Author: sravanyabendi

Data Structures/Stacks/balanced_parentheses.py

@@ -0,0 +1,28 @@
+## Python3 code to Check for 
+# balanced parentheses in an expression
+
+
+#Function to check parentheses
+def validparentheses(s):
+    open_brace=["{","[","("]
+    closed_brace=["}","]",")"]
+    stack=[]
+    for i in s:
+        if i in open_brace:
+            stack.append(i)
+        elif i in closed_brace:
+            p=closed_brace.index(i)
+            if len(stack)>0 and open_brace[p]==stack[len(stack)-1]:
+                stack.pop()
+            else:
+                return False
+    if(len(stack)==0): #return true if given expression is balanced
+        return True
+    else:
+        return False   #return false is not balanced
+    
+s=input("Enter the Expression to be evaluated:")
+if(validparentheses(s)):
+    print("Expression is Balanced")
+else:
+    print("Expression is Unbalanced")