""" Output: Enter a Postfix Equation (space separated) = 5 6 9 * + Symbol | Action | Stack ----------------------------------- 5 | push(5) | 5 6 | push(6) | 5,6 9 | push(9) | 5,6,9 | pop(9) | 5,6 | pop(6) | 5 * | push(6*9) | 5,54 | pop(54) | 5 | pop(5) | + | push(5+54) | 59 Result = 59 """ import operator as op def Solve(Postfix): Stack = [] Div = lambda x, y: int(x / y) # noqa: E731 integer division operation Opr = { "^": op.pow, "*": op.mul, "/": Div, "+": op.add, "-": op.sub, } # operators & their respective operation # print table header print("Symbol".center(8), "Action".center(12), "Stack", sep=" | ") print("-" * (30 + len(Postfix))) for x in Postfix: if x.isdigit(): # if x in digit Stack.append(x) # append x to stack # output in tabular format print(x.rjust(8), ("push(" + x + ")").ljust(12), ",".join(Stack), sep=" | ") else: B = Stack.pop() # pop stack # output in tabular format print("".rjust(8), ("pop(" + B + ")").ljust(12), ",".join(Stack), sep=" | ") A = Stack.pop() # pop stack # output in tabular format print("".rjust(8), ("pop(" + A + ")").ljust(12), ",".join(Stack), sep=" | ") Stack.append( str(Opr[x](int(A), int(B))) ) # evaluate the 2 values popped from stack & push result to stack # output in tabular format print( x.rjust(8), ("push(" + A + x + B + ")").ljust(12), ",".join(Stack), sep=" | ", ) return int(Stack[0]) if __name__ == "__main__": Postfix = input("\n\nEnter a Postfix Equation (space separated) = ").split(" ") print("\n\tResult = ", Solve(Postfix))