Question

我正在阅读“绝对初学者的Python编程（第3版）”一书。我在介绍自定义模块的章节中，我相信这可能是书中编码的错误，因为我已经检查了5到6次并完全匹配。

首先我们有一个自定义模块 games.py

class Player(object):
    """ A player for a game. """
    def __init__(self, name, score = 0):
        self.name = name
        self.score = score

    def __str__(self):
        rep = self.name + ":\t" + str(self.score)
        return rep

def ask_yes_no(question):
    """ Ask a yes or no question. """
    response = None
    while response not in ("y", "n"):
        response = input(question).lower()
    return response

def ask_number(question, low, high):
    """ Ask for a number within a range """
    response = None
    while response not in range (low, high):
        response = int(input(question))
    return response

if __name__ == "__main__":
    print("You ran this module directly (and did not 'import' it).")
    input("\n\nPress the enter key to exit.")

现在是 SimpleGame.py

import games, random


print("Welcome to the world's simplest game!\n")

again = None
while again != "n":
    players = []

num = games.ask_number(question = "How many players? (2 - 5): ", low = 2, high = 5)
    for i in range(num):
        name = input("Player name: ")
        score = random.randrange(100) + 1
        player = games.Player(name, score)
        players.append(player)

    print("\nHere are the game results:")
    for player in players:
        print(player)

    again = games.ask_yes_no("\nDo you want to play again? (y/n): ")

input("\n\nPress the enter key to exit.")

所以这正是代码出现在书中的方式。当我运行程序时，我在IndentationError收到错误for i in range(num):。我预计会发生这种情况所以我更改了它并删除了从for i in range(num)到again = games.ask_yes_no("\nDo you want to play again? (y/n): ")每行前面的1个标签或4个空格。

此后输出为"Welcome to the world's simplest game!"，就是这样。

我想知道是否有人可以让我知道为什么会这样？

此外，在我添加PYTHONPATH的路径后，在Eclipse中识别import games模块。

Answer 1

我自己实际上有这本书。是的，这是一个错字。以下是如何解决它：

# SimpleGame.py
import games, random


print("Welcome to the world's simplest game!\n")

again = None
while again != "n":
    players = []

    num = games.ask_number(question = "How many players? (2 - 5): ", low = 2, high = 5)
    for i in range(num):
        name = input("Player name: ")
        score = random.randrange(100) + 1
        player = games.Player(name, score)
        players.append(player)

    print("\nHere are the game results:")
    for player in players:
        print(player)

    again = games.ask_yes_no("\nDo you want to play again? (y/n): ")

input("\n\nPress the enter key to exit.")

我所做的只是缩进num 4个空格，并用第一个for循环排成一行。

Answer 2

这里有一个无限循环：

again = None
while again != "n":
    players = []

Answer 3

如果这与书中的印刷方式完全一致，那么这本书确实有错误。

你有这两行：

num = games.ask_number(question = "How many players? (2 - 5): ", low = 2, high = 5)
    for i in range(num):

第二个比第一个缩进得更多。如果第一个是像for或while或if这样的块介绍者，那么这是合法的。既然不是，那就是IndentationError。而这正是Python告诉你的。

（你可能错误地复制了一些东西。你也可能混合了标签和空格，所以它实际上在你的编辑器中是正确的，但它看起来不错。但如果这些都不是真的，这本书是错的。）

所以，你试图通过dedenting for循环上的所有内容来修复它。

但是当你这样做时，while循环下只剩下一行：

while again != "n":
    players = []

没有任何东西可以改变again到"n"，所以这将永远旋转，什么都不做，而不是转移到程序的其余部分。

所以，您可能想要做的是缩进 num = …行到与for i…行相同的级别，所以他们两个（以及所有的东西） after）在while循环内结束。

Python自定义模块 - 示例代码出错

3 个答案: