Sentence every day: Errors happen in the details, and success depends on the system.
if statement processing list
requested_toppings=['mushrooms','gress peppers','extra cheese']
for requested_topping in requested_toppings:
print("adding"+requested_topping+'.')
print("\nFinished making your pizza!")
requested_toppings=['mushrooms','gress peppers','extra cheese']
for requested_topping in requested_toppings:
if requested_topping=='gress peppers':
print("Sorry,we are out of green peppers right now")
else:
print("adding "+requested_topping+'.')
print("\ nFinished Making your Pizza! " )
# traversing the list when requested_topping equal gress peppers, Print else statement, the if statement contrary Print
requested_toppings=[]
if requested_toppings:
for requested_topping in requested_toppings:
print("adding"+requested_topping+'.')
print("\nFinished making your pizza!")
else:
print("Are you sure you want a plain pizza?")
# 当列表为空时,for循环无法执行,执行了else
avaiblable_toppings=['mushrooms','olives','gress peppers','pepperoni','pineapple','extra cheese']
requested_toppings=['mushrooms','french fries','extra cheese']
for requested_topping in requested_toppings:
if requested_topping in avaiblable_toppings:
print("adding"+requested_topping+'.')
else:
print("Sorry,we don't have"+requested_topping+".")
Print ( " \ nFinished Making your Pizza! " )
# traversing the list requested_toppings, when one element is not present in the list avaiblable_toppings, the else statement is executed, whereas if statement execution