<p>缩进在Python中非常重要。根据缩进的实现方式,执行条件的代码块</p>
<p>错位缩进可能导致代码块意外执行</p>
<p><strong>这是订购程序的工作演示</strong></p>
<pre><code># File name: order-demo.py
moreItems = True
while (moreItems == True):
order = input("\n What would you like to order?\n"
+ " 1: Burger\n 2: Fries\n 3: Drink\n Answer = ")
if ((order == "1") or (order == "2") or (order == "3")):
print("You have selected to order " + order)
print("Your item has been added to the basket.\n")
else:
print("Invalid Input")
check = input("Is this your final item?: \n 1: Yes \n 2: No \n Answer = ")
if check == "1":
print("\n Thank you. Please proceed to checkout.")
moreItems = False
elif check == "2":
print("Please continue your shopping")
else:
print("Invalid input")
</code></pre>
<p><strong>输出</strong></p>
<pre><code>$ python3 order-demo.py
What would you like to order?
1: Burger
2: Fries
3: Drink
Answer = 1
You have selected to order 1
Your item has been added to the basket.
Is this your final item?:
1: Yes
2: No
Answer = 2
Please continue your shopping
What would you like to order?
1: Burger
2: Fries
3: Drink
Answer = 2
You have selected to order 2
Your item has been added to the basket.
Is this your final item?:
1: Yes
2: No
Answer = 1
Thank you. Please proceed to checkout.
$
</code></pre>