python 函数调用未按预期打印

Question

所以我有 2 个函数 - displayHand(hand) 和 calculateHandlen(hand)

def displayHand(hand):
    """
    Displays the letters currently in the hand.

    For example:
    >>> displayHand({'a':1, 'x':2, 'l':3, 'e':1})
    Should print out something like:
       a x x l l l e
    The order of the letters is unimportant.

    hand: dictionary (string -> int)
    """
    for letter in hand.keys():
        for j in range(hand[letter]):
             print(letter,end=" ")       
    print() 

def calculateHandlen(hand):
    """ 
    Returns the length (number of letters) in the current hand.

    hand: dictionary (string-> int)
    returns: integer
    """
    handLen = 0
    for i in hand:
        handLen = handLen + hand.get(i,0)

    return handLen

另一个函数中有一个循环依赖于上述函数 -

def playHand(hand, wordList, n): 
"""
   hand = dictionary 
   wordList = list of valid words
   n = an integer passed while function call  
"""
    totalscore = 0
    while(calculateHandlen(hand)>0):
        print("Current Hand: " +str(displayHand(hand)))

        newWord = input('Enter word, or a "." to indicate that you are finished: ')

playHand()函数调用如下：

wordList = loadWords() #loadWords could be a list of words
playHand({'n':1, 'e':1, 't':1, 'a':1, 'r':1, 'i':2}, wordList, 7)

我希望输出为：

Current Hand: n e t a r i i 
Enter word, or a "." to indicate that you are finished:

但是，它显示以下内容：

n e t a r i i   
Current Hand: None  
Enter word, or a "." to indicate that you are finished:

不知道我哪里错了。

注意：我不能对前两个函数进行任何更改。

Answer 1

displayHand() 没有 return 任何东西，所以默认的 None 是 returned。当你调用它时，它会直接打印输出。

如果不允许更改displayHand()，则需要先打印标签，然后调用函数：

print("Current Hand: ", end='')
displayHand(hand)

end='' 删除换行符 print() 通常会写。

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