(postfix)
| 50 | |
| 51 | |
| 52 | def calculate_postfix(postfix): |
| 53 | ret = "" |
| 54 | s = [] |
| 55 | postfix = postfix.strip() |
| 56 | postfix_arr = postfix.split(' ') |
| 57 | for token in postfix_arr: |
| 58 | if token in ["+", "-", "*", "/"]: |
| 59 | b = s.pop() |
| 60 | a = s.pop() |
| 61 | if token == "+": |
| 62 | s.append(a + b) |
| 63 | elif token == "-": |
| 64 | s.append(a - b) |
| 65 | elif token == "*": |
| 66 | s.append(a * b) |
| 67 | elif token == "/": |
| 68 | s.append(a / b) |
| 69 | else: |
| 70 | s.append(float(token)) |
| 71 | ret = str(s.pop()) |
| 72 | return ret |
| 73 | |
| 74 | from tkinter import * |
| 75 |