Udacity進入計算機科學（Python）第2課PS郵票 - 輸出包括「無」

Question

我已經搜索了互聯網，並嘗試了代碼的變體，但我只是不明白爲什麼我會得到輸出「無」結果，當時我在Udacity的計算機科學入門2課中學習PS 2。

這裏是PS和我目前的狀態：

# Define a procedure, stamps, which takes as its input a positive integer in 
# pence and returns the number of 5p, 2p and 1p stamps (p is pence) required 
# to make up that value. The return value should be a tuple of three numbers 
# (that is, your return statement should be followed by the number of 5p, 
# the number of 2p, and the nuber of 1p stamps). 
# 
# Your answer should use as few total stamps as possible by first using as 
# many 5p stamps as possible, then 2 pence stamps and finally 1p stamps as 
# needed to make up the total. 
# 


def stamps(n): 
    if n > 0: 
     five = n/5 
     two = n % 5/2 
     one = n % 5 % 2 
     print (five, two, one) 
    else: 
     print (0, 0, 0) 


print stamps(8) 
#>>> (1, 1, 1) # one 5p stamp, one 2p stamp and one 1p stamp 
print stamps(5) 
#>>> (1, 0, 0) # one 5p stamp, no 2p stamps and no 1p stamps 
print stamps(29) 
#>>> (5, 2, 0) # five 5p stamps, two 2p stamps and no 1p stamps 
print stamps(0) 
#>>> (0, 0, 0) # no 5p stamps, no 2p stamps and no 1p stamps 

產生的輸出：

(1, 1, 1) 
None 
(1, 0, 0) 
None 
(5, 2, 0) 
None 
(0, 0, 0) 
None 

誰能請解釋一下其中的「無」是哪裏來的？

Answer 1

您正在調用打印結果的函數，然後打印該函數的返回值爲None。

您應該選擇一種顯示數據的方法。 無論是打印只在函數內部：

def stamps(n): 
    if n > 0: 
     five = n/5 
     two = n % 5/2 
     one = n % 5 % 2 
     print five, two, one 
    else: 
     print 0, 0, 0 

stamps(8) 
stamps(5) 
stamps(29) 
stamps(0) 

或者使用return：

def stamps(n): 
    if n > 0: 
     five = n/5 
     two = n % 5/2 
     one = n % 5 % 2 
     return five, two, one 
    else: 
     return 0, 0, 0 


print stamps(8) 
print stamps(5) 
print stamps(29) 
print stamps(0)