我目前正在代码中使用一个名为correct的全局变量。考虑到全局变量不受欢迎，有没有更好的方法来设置我的代码来"保护"全局变量？
from random import randint
from random import choice
lower = int(raw_input("Enter a lower integer constraint: "))
higher = int(raw_input("Enter a higher integer constraint: "))
correct = 0
def gen_randoms(lower, higher):
integers = list()
for x in xrange(4):
rand_int = randint(lower, higher)
integers.append(rand_int)
return integers
def gen_equation(integers):
nums = map(str, integers)
operators = ['*', '+', '-']
equation = 'num op num op num op num'
while 'op' in equation:
equation = equation.replace('op', choice(operators), 1)
while 'num' in equation:
equation = equation.replace('num', choice(nums), 1)
print equation
return equation
def evaluate(equation):
answer = eval(equation)
print answer
return answer
def compare_answers(gen_answer, game):
global correct
user_answer = int(raw_input("What is the answer? "))
if user_answer == gen_answer:
correct += 1
print 'Correct!'
print 'Current streak: %s' % str(correct)
game()
else:
print 'Incorrect!'
correct = 0
game()
def game():
nums = gen_randoms(lower, higher)
this_equation = gen_equation(nums)
gen_answer = evaluate(this_equation)
compare_answers(gen_answer, game)
game()
我可能会这样做：
#!/usr/bin/python
"""Equation solving game."""
from random import randint
from random import choice
def gen_randoms(lower, higher):
"""Generates four random numbers between provided bounds."""
integers = [randint(lower, higher) for x in range(4)]
return integers
def gen_equation(integers):
"""Generates a random equation from four provided integers."""
nums = [str(i) for i in integers]
operators = ['*', '+', '-']
equation = 'num op num op num op num'
while 'op' in equation:
equation = equation.replace('op', choice(operators), 1)
while 'num' in equation:
equation = equation.replace('num', choice(nums), 1)
return equation
def evaluate(equation):
"""Evaluates an equation."""
return eval(equation)
def main():
"""Main game function."""
lower = int(raw_input("Enter a lower integer constraint: "))
higher = int(raw_input("Enter a higher integer constraint: "))
nums = gen_randoms(lower, higher)
streak = 0
while True:
this_equation = gen_equation(nums)
print this_equation
user_answer = raw_input("What is the answer? ('Q' to quit) ")
if user_answer.lower()[0] == 'q':
break
gen_answer = evaluate(this_equation)
print 'The answer was: %d' % gen_answer
if gen_answer == int(user_answer):
streak += 1
print 'Correct!'
print 'Current streak: %d' % streak
else:
streak = 0
print 'Incorrect!'
if __name__ == "__main__":
main()
一些评论：
- 每个函数通常只应该做一件事，所以如果一个函数计算一个方程，通常最好不要让它打印方程
- 当你这样做的时候，弄清楚变量应该去哪里会变得容易得多，因为当每个函数做几件不同的事情时，你不需要像必须的那样传递它们
- 这里的主要游戏逻辑非常简单，你不需要把它从你的主要
game()函数（在我的例子中是main()函数）中分解出来，把它留在那里也不会让事情变得过于复杂。如果你想做更多的错误检查（例如，查看用户是否输入了一个无效的号码，如果是，你想回去要求更多的输入），那么你可能想再细分一些
类似这样的东西：
def game(correct=0):
nums = gen_randoms(lower, higher)
this_equation = gen_equation(nums)
gen_answer = evaluate(this_equation)
correct = compare_answers(gen_answer, game, correct)
game(correct)
添加此项：
def game():
correct = 0
while True:
nums = gen_randoms(lower, higher)
this_equation = gen_equation(nums)
gen_answer = evaluate(this_equation)
user_answer = int(raw_input("What is the answer? "))
if user_answer == gen_answer:
correct += 1
print 'Correct!'
print 'Current streak: %s' % str(correct)
else:
print 'Incorrect!'
correct = 0
然后删除这些旧代码：game()、compare_answers()和全局变量correct。
- 从
compare_answers中删除global correct - 设置CCD_ 9以接受具有默认值CCD_ 11的关键字参数CCD_。
def game(correct =0) - 设置
compare_answers以获取第三个参数correct - 从
compare_answers调用game时通过correct
即：
def compare_answers(gen_answer, game, correct):
user_answer = int(raw_input("What is the answer? "))
if user_answer == gen_answer:
correct += 1
print 'Correct!'
print 'Current streak: %s' % str(correct)
game(correct)
else:
print 'Incorrect!'
correct = 0
game(correct)
def game(correct = 0):
nums = gen_randoms(lower, higher)
this_equation = gen_equation(nums)
gen_answer = evaluate(this_equation)
compare_answers(gen_answer, game, correct)
game()
我最终采纳了@JoelCornett的建议，创建了一个类：
from random import randint
from random import choice
class Math_Problem_Generator(object):
def __init__(self):
self.lower = int(raw_input("Enter a lower integer constraint: "))
self.higher = int(raw_input("Enter a higher integer constraint: "))
self.correct = 0
self.game(self.correct)
def gen_randoms(self, lower, higher):
integers = list()
for x in xrange(4):
rand_int = randint(lower, higher)
integers.append(rand_int)
return integers
def gen_equation(self, integers):
nums = map(str, integers)
operators = ['*', '+', '-']
equation = 'num op num op num op num'
while 'op' in equation:
equation = equation.replace('op', choice(operators), 1)
while 'num' in equation:
equation = equation.replace('num', choice(nums), 1)
print equation
return equation
def evaluate(self, equation):
answer = eval(equation)
print answer
return answer
def compare_answers(self, gen_answer):
user_answer = int(raw_input("What is the answer? "))
if user_answer == gen_answer:
self.correct += 1
print 'Correct!'
print 'Current streak: %s' % str(self.correct)
self.game(self.correct)
else:
print 'Incorrect!'
self.correct = 0
self.game(self.correct)
def game(self, correct):
nums = self.gen_randoms(self.lower, self.higher)
this_equation = self.gen_equation(nums)
gen_answer = self.evaluate(this_equation)
self.compare_answers(gen_answer)
self.game()
Math_Problem_Generator()
在调用者中收集结果，然后打印计数。这个版本去掉了其他全局变量lower和higher。
def compare_answers(gen_answer):
user_answer = int(raw_input("What is the answer? "))
return user_anser == gen_answer
def game():
correct = 0
play_again = 'Y'
while play_again.lower() == 'y':
lower = int(raw_input("Enter a lower integer constraint: "))
higher = int(raw_input("Enter a higher integer constraint: "))
nums = gen_randoms(lower, higher)
this_equation = gen_equation(nums)
gen_answer = evaluate(this_equation)
if compare_answers(gen_answer):
correct += 1
print('You were right! Your winning streak is {0}'.format(correct))
else:
print('Sorry, your answer was wrong. :(')
correct = 0
play_again = raw_input('Would you like to play again? (Y/N): ')