如何重复我的初始输入代码？

Question

我正在用Python做一个计算器，这是我课堂作业的一部分（基本运算，包括加法、减法、乘法和除法）。我有一个打印菜单，用户可以从中选择他们想要使用的运算，然后输入他们的整数，最后打印出答案。我的问题是，我需要重复用户选择的运算类型。因为我刚接触编程，所以任何帮助都非常感谢。

这是我的代码：

print ("1 = addition")
print ("2 = subtraction")
print ("3 = multiplication")
print ("4 = division")
print ("5 = Exit program\n")

x = int (input ("What operation would you like to perform?: ")) #prompts user for operation

if (x == 1): #if operation chose is addition then this line will exacute
  int1 = input ("Enter first integer: ")
  int1 = int (int1)
  int2 = input ("Enter second integer: ")
  int2 = int (int2)
  sum = int1 + int2
  print ("Sum is:", sum)

elif (x == 2): #if operation chose is subtraction then this line will exacute
  int1 = input ("Enter first integer: ")
  int1 = int (int1)
  int2 = input ("Enter second integer: ")
  int2 = int (int2)
  dif = int1 - int2
  print ("Difference is:", dif)

elif (x == 3): #if operation chose is multiplication then this line will exacute
  int1 = input ("Enter first integer: ")
  int1 = int (int1)
  int2 = input ("Enter second integer: ")
  int2 = int (int2)
  mult = int1 * int2
  print ("Multiplication is:", mult)

elif (x == 4): #if operation chose is division then this line will exacute
  int1 = input ("Enter first integer: ")
  int1 = int (int1)
  int2 = input ("Enter second integer: ")
  int2 = int (int2)
  div = int1 / int2
  print ("Division is: %.2f" % div)

elif (x == 5):
  print ("goodbye")
  quit()

Answer 1

你需要了解一下基本的流程控制。这里有一段相关的 Python教程。

这可以通过 for 循环或者 while 循环来实现。下面是这两种方法的例子：

for a in range(10):
    print a

b=0
while b<0:
    print b
    b= b+1

Answer 2

使用一个 while 循环：

这个循环会一直重复，直到 x 不再等于 5 为止。

while True:
    #your code

    elif x == 5:       # no need of () around conditions
    print ("goodbye")
    break             # exit the while loop 

Answer 3

你可以把那段代码分成一个函数：

print "1 = addition"
print "2 = subtraction"
print "3 = multiplication"
print "4 = division"
print "5 = Exit program\n"

def maths(choice):
    if choice == 1: #if operation chose is addition then this line will exacute
       int1 = input("Enter first integer:")
       int2 = input ("Enter second integer: ")
       sum = int1 + int2
       print "Sum is:", sum

    elif choice == 2: #if operation chose is subtraction then this line will exacute
       int1 = input("Enter first integer: ")
       int2 = input("Enter second integer: ")
       dif = int1 - int2
       print "Difference is:", dif

    elif choice == 3: #if operation chose is multiplication then this line will exacute
       int1 = input("Enter first integer: ")
       int2 = input("Enter second integer: ")
       mult = int1 * int2
       print "Multiplication is:", mult

    elif choice == 4: #if operation chose is division then this line will exacute
       int1 = input("Enter first integer: ")
       int2 = input ("Enter second integer: ")
       div = int1 / int2
       print "Division is: %.2f" % div

    elif choice == 5:
       print "goodbye"
       quit()

while True: # "While True, repeat everything below":
    maths(input("What operation would you like to perform?: "))

---

补充说明：看起来你提到的是 Python 2.7，所以我帮你整理了一下代码。

你不需要使用 int(int1) 和 int(int2)，因为 input() 输入的内容本身就不是字符串。也就是说：

>>> number = input('Enter a number! ') # Let's say I put 5
>>> print number
5 # Notice it's not a string (no ' ')

而 raw_input() 则会这样处理：

>>> number = raw_input('Enter a number! ')
>>> print number
'5' # 5 is a string, not an integer. And so int() would be required