Python 我怎样才能随机选择一个数学运算符并用它提出重复的数学问题？
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How can I randomly choose a maths operator and ask recurring maths questions with it?
提问by Obahar
I have a simple maths task I'm having problems executing, involving the random import. The idea is that there is a quiz of 10 randomly generated questions. I've got the numbers ranging from (0,12) using the random.randint function, that works fine. Its the next bit of choosing a random operator I'm having problems with ['+', '-', '*', '/'].
我有一个简单的数学任务，我在执行时遇到问题，涉及随机导入。这个想法是有 10 个随机生成的问题的测验。我使用 random.randint 函数得到了从 (0,12) 范围内的数字，效果很好。它是选择随机运算符的下一点，我在使用 ['+'、'-'、'*'、'/'] 时遇到了问题。
I have my more sophisticated coding back at school, but this is my practise one that all I need is the ability to randomly create a question and ask it, whilst also being able to answer it itself to determine if the answer given is correct. Here's my code:
我在学校有更复杂的编码，但这是我的练习，我所需要的只是随机创建问题并提出问题的能力，同时还能够自行回答以确定给出的答案是否正确。这是我的代码：
import random
ops = ['+', '-', '*', '/']
num1 = random.randint(0,12)
num2 = random.randint(0,10)
operation = random.choice(ops)
print(num1)
print(num2)
print(operation)
maths = num1, operation, num2
print(maths)
As of right now though, my output is a little messed up. For example:
但截至目前，我的输出有点混乱。例如：
3
6
*
(3, '*', 6)
Clearly it can't determine the answer from (3, '*', 6). I'll be turning this operation into a subroutine in my other program, but it needs to work first!
显然它不能从 (3, '*', 6) 确定答案。我将把这个操作变成我另一个程序中的一个子程序，但它需要先工作！
And forgive me if its not very well done, this was a quick recreation of the task I left at school, and I'm also fairly new at this with limited knowledge. Thanks in advance!
如果它做得不好，请原谅我，这是我在学校留下的任务的快速重新创建，而且我对这方面的知识也很陌生。提前致谢！
采纳答案by rwflash
There is a function in Python called eval() that evaluates strings which contain mathematical expressions.
Python 中有一个名为 eval() 的函数，用于计算包含数学表达式的字符串。
import random
ops = ['+', '-', '*', '/']
num1 = random.randint(0,12)
num2 = random.randint(0,10)
operation = random.choice(ops)
print(num1)
print(num2)
print(operation)
maths = eval(str(num1) + operation + str(num2))
print(maths)
You need to convert your numbers to strings because the function is expecting something like the string '4*2', '3+1' etc. etc.
您需要将数字转换为字符串，因为该函数需要类似字符串 '4*2'、'3+1' 等的内容。
回答by Cory Kramer
How about you make a dictionary that maps the operator's character (e.g. '+') to the operator (e.g. operator.add). Then sample that, format you string, and perform the operation.
您如何制作一个将运算符的字符（例如“+”）映射到运算符（例如operator.add）的字典。然后采样，格式化你的字符串，并执行操作。
import random
import operator
Generating a random mathematical expression
生成随机数学表达式
def randomCalc():
ops = {'+':operator.add,
'-':operator.sub,
'*':operator.mul,
'/':operator.truediv}
num1 = random.randint(0,12)
num2 = random.randint(1,10) # I don't sample 0's to protect against divide-by-zero
op = random.choice(list(ops.keys()))
answer = ops.get(op)(num1,num2)
print('What is {} {} {}?\n'.format(num1, op, num2))
return answer
Asking the user
询问用户
def askQuestion():
answer = randomCalc()
guess = float(input())
return guess == answer
Finally making a multi-question quiz
最后做一个多问题测验
def quiz():
print('Welcome. This is a 10 question math quiz\n')
score = 0
for i in range(10):
correct = askQuestion()
if correct:
score += 1
print('Correct!\n')
else:
print('Incorrect!\n')
return 'Your score was {}/10'.format(score)
Some testing
一些测试
>>> quiz()
Welcome. This is a 10 question math quiz
What is 8 - 6?
2
Correct!
What is 10 + 6?
16
Correct!
What is 12 - 1?
11
Correct!
What is 9 + 4?
13
Correct!
What is 0 - 8?
-8
Correct!
What is 1 * 1?
5
Incorrect!
What is 5 * 8?
40
Correct!
What is 11 / 1?
11
Correct!
What is 1 / 4?
0.25
Correct!
What is 1 * 1?
1
Correct!
'Your score was 9/10'
回答by Wayne Askey
Use a list for the operators e.g operator = ['+', '',' -', '/'] then you can use Then you can use random choice on your list to call a random operator (+,-,,/) x = (random.choice(operator)) Finally you will need to convert your num1 & num2 to strings something like this eval(str(num1)+ x + str(num2)) That should make your quiz completly random
使用运算符列表，例如 operator = ['+', ' ',' -', '/'] then you can use Then you can use random choice on your list to call a random operator (+,-,,/ ) x = (random.choice(operator)) 最后，您需要将您的 num1 和 num2 转换为类似这样的字符串 eval(str(num1)+ x + str(num2)) 这应该使您的测验完全随机
