Python缺少self引數

您好 :> 我正在學習 python 物件編程。我做了簡單的代碼：

import random
drawn = []
class Lottery():
    def __init__(self, letter, drawn):
        self.letters = ['a', 'b', 'c', 'd', 'f', 'g', 'h']
        self.letter = letter
        self.drawn = drawn

    def drawnumbers():
        number = random.randint(0, 10)
        return number
    def drawletters(self):
        letter = random.choice(self.letters)
        return letter()

    for i in range(0,9):
        drawn.append(drawnumbers())
    for i in range(0,3):
        drawn.append(drawletters())
    print(drawn)

這是錯誤：

Traceback (most recent call last):
  File "C:/Users/pawee/PycharmProjects/pythonProject1/lottery.py", line 3, in <module>
    class Lottery():
  File "C:/Users/pawee/PycharmProjects/pythonProject1/lottery.py", line 19, in Lottery
    drawn.append(drawletters())
TypeError: drawletters() missing 1 required positional argument: 'self'

我做錯了什么？

uj5u.com熱心網友回復：

因此，當您定義屬于類的方法時，它們都將“self”作為第一個引數。

定義類時也不包括括號，除非它是從另一個類繼承的

但是，還有幾個錯誤。

我認為這可能是格式錯誤，但最后幾行需要不縮進，因此它們不在課堂上。

如果它們應該是類的一部分，那么您將希望將它們放在自己的方法中（也包括 self 引數）。

為了使對彩票類的呼叫在沒有實體的情況下作業，它們也必須是靜態的。

所以讓它運行需要讓你的代碼看起來像這樣......

import random
drawn=[]
class Lottery: #no parenthesis
    def __init__(self, letter, drawn):
        self.letters = ['a', 'b', 'c', 'd', 'f', 'g', 'h']
        self.letter = letter
        self.drawn = drawn
    
    @staticmethod
    def drawnumbers(self): #include self
        number = random.randint(0, 10)
        return number

    @staticmethod
    def drawletters(self): #include self
        letter = random.choice(self.letters)
        return letter #no parenthesis

#unindent so we aren't in the class anymore
for i in range(0,9):
    drawn.append(Lottery.drawnumbers())
for i in range(0,3):
    drawn.append(Lottery.drawletters())
print(drawn) 
#at this point, drawn is not associated with the lottery class
# to associate it, you need to make a variable out of the class
lotteryObj = Lottery("A", drawn) #it takes 2 arguments, letter and drawn
print(lotteryObj.drawn) #=> [...]
print(lotteryObj.letter) #=> "A"

然而，這并不是真正的類應該如何作業。

如果您想創建一個彩票類，最好讓該類保存它使用的資料，并擁有影響該資料的方法。

這是默認引數派上用場的地方。它們允許您為您的類定義不需要給出的引數。

這樣，您可以獲得一些抽獎號碼的串列，將其提供給您的彩票課程，然后將其添加到抽出更多號碼/字母的串列中。

import random
drawn=[]
class Lottery: #no parenthesis
    def __init__(self, drawn=[]): #default for drawn, letter not needed
        self.letters = ['a', 'b', 'c', 'd', 'f', 'g', 'h']
        self.drawn = drawn #if you don't give the class a list, it makes an empty list

    def drawnumbers(self): #include self
        number = random.randint(0, 10)
        #instead of returning, change the list this class has using self
        self.drawn.append(number)

    def drawletters(self): #include self
        letter = random.choice(self.letters)
        self.drawn.append(letter)
    #you can add a print method or get methods for printing or getting the drawn list

#unindent so we aren't in the class anymore
lotto1 = Lottery()
lotto2 = Lottery([1]) #give it a list with something in it
for i in range(0,9):
    lotto1.drawnumbers()
    lotto2.drawnumbers()
for i in range(0,3):
    lotto1.drawletters()
    lotto2.drawletters()
print(lotto1.drawn)
print(lotto2.drawn) 

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