在函数中使用if"x"来执行计算器但不生成总计

Question

我是Python的新手,我的代码遇到了问题,我正在使用if in函数来做一个蔬菜水果商的计算器,当输入三个苹果正在购买时,总数正在生成为0英镑时应该是3.90英镑

total = 0


print "Welcome to the green grocers, what would you like?"
print "1. Apples"
print "2: Bananas"
print "3. Oranges"
print "4. Total"



fruit = raw_input("What would you like?")

if "1" in fruit:
   q = input("How many?")
   total + (q*1.3)
   fruit = raw_input("What would you like?")

if "2" in fruit:
   g = input("How many?")
   total + (g*1.5)
   fruit = raw_input("What would you like?")

if "3" in fruit:
   l = input("How many?")
   total = (l*1.6)
   fruit = raw_input("What would you like?")

   if "4" in fruit:
   print "Your total is £", total

Answer 1

你需要:

total = total + (q*1.3)

要么:

total += (q*1.3)

整数是不可变的,只是做total + (q*1.3)不会影响total,它只是返回一个新的整数.

>>> x = 1
>>> x + 2   # Simply returns a new value, doesn't affects `x`
3
>>> x       # `x` is still unchanged
1
>>> x += 1  # Assign the new value back to `x`
>>> x       # `x` is now updated.
2