python：小学算术测验-将结果保存到.txt文件

我的任务是为小学生做一个小测验。它向他们随机提出问题，然后输出结果。在那之前，程序运行得非常好。对于我的任务，我必须将用户的“用户名”和他们的“正确答案”存储到a“.txt”文件中。该程序似乎可以运行，但没有任何内容存储在“classScores.txt”文件中。我对编码很陌生，所以对我放松点。任何帮助都将不胜感激：）

在

a+

模式下打开，以避免覆盖文件。问题在于您的代码中，您忘记了关闭文件。但是，我建议您使用

和open（）

方法，这比

open（）

好得多

该程序似乎可以运行，但没有任何内容存储在“classScores.txt”中 文件

您的代码将正确地写入该文件——但最好在处理完文件后关闭该文件。正如Antti Haapala在评论中指出的，您应该这样做：

with open("classScores.txt", "a") as my_file:  #my_file is automatically closed after execution leaves the body of the with statement
    username = 'Sajjjjid'
    correct_answers = 3

    my_file.write("{}:{}\n".format(username,correct_answers))

我对编码很陌生

通常，初学者的规则是：

永远不要使用eval（）

以下是一些更好的选择：

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    def add(x, y):
        return x+y

    def sub(x, y):
        return x-y

    def mult(x, y):
        return x*y

    ops = {
        '+': add,
        '-': sub,
        '*': mult,
    }

    keys = list(ops.keys()) #=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '*' 
    operation = ops[rand_key]  #e.g. mult

    correct_result = operation(num1, num2)

如果定义一个函数，然后使用不带尾随的

（）

的函数名，那么该函数就是一个值，就像数字1一样，并且可以将该函数赋值给一个变量，就像任何其他值一样。如果要执行存储在变量中的函数，请在变量名称后使用尾随的

（）

：

def func():
    print('hello')

my_var = func
my_var()  #=>hello

python还允许您创建匿名（未命名）函数，如下所示：

my_func = lambda x, y: x+y
result = my_func(1, 2)
print(result) #=>3

import random
import math
import operator as op

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': op.add,  #Just like the add() functions defined above
        '-': op.sub,
        '*': op.mul,
    }

    keys = list(ops.keys()) #=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '-'
    operation = ops[rand_key]  #e.g. op.sub

    correct_result = operation(num1, num2)

你为什么要这么做？它可以使您的代码更加紧凑：

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': lambda x, y: x + y,  #You can define the function right where you want to use it.
        '-': lambda x, y: x - y,
        '*': lambda x, y: x * y,
    }

    keys = list(ops.keys()) ##=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '*' 
    operation = ops[rand_key]  #e.g. lambda x, y: x*y

    correct_result = operation(num1, num2)

但是，事实证明python为您定义了所有这些函数——在

操作符模块中。因此，您可以使代码更加紧凑，如下所示：

my_func = lambda x, y: x+y
result = my_func(1, 2)
print(result) #=>3

import random
import math
import operator as op

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': op.add,  #Just like the add() functions defined above
        '-': op.sub,
        '*': op.mul,
    }

    keys = list(ops.keys()) #=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '-'
    operation = ops[rand_key]  #e.g. op.sub

    correct_result = operation(num1, num2)

下面是一个完整的示例，其中包含一些其他改进：

import random
import math
import operator as op

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': op.add,
        '-': op.sub,
        '*': op.mul,
    }

    keys = list(ops.keys()) ##=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '+' 
    operation = ops[rand_key]  #e.g. op.add

    correct_result = operation(num1, num2)

    print ("What is {} {} {}?".format(num1, rand_key, num2))
    user_answer= int(input("Your answer: "))

    if user_answer != correct_result:
        print ("Incorrect. The right answer is {}".format(correct_result))
        return False
    else:
        print("Correct!")
        return True

username = input("What is your name? ")
print("Hi {}! Welcome to the Arithmetic quiz...".format(username))

correct_answers = 0
num_questions = 3

for i in range(num_questions):
    if test():
        correct_answers +=1


print("{}: You got {}/{} questions correct.".format(
    username, 
    correct_answers, 
    num_questions,
    #'question' if (correct_answers==1) else 'questions'
))

不要这样故意破坏你的问题——无论是对那些花时间帮助你的人，还是对那些可能会觉得有用的未来访客，这都是粗鲁的。
import random
import math
import operator as op

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': op.add,  #Just like the add() functions defined above
        '-': op.sub,
        '*': op.mul,
    }

    keys = list(ops.keys()) #=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '-'
    operation = ops[rand_key]  #e.g. op.sub

    correct_result = operation(num1, num2)

import random
import math
import operator as op

def test():
    num1 = random.randint(1, 10)
    num2 = random.randint(1, num1)

    ops = {
        '+': op.add,
        '-': op.sub,
        '*': op.mul,
    }

    keys = list(ops.keys()) ##=> ['+', '*', '-']
    rand_key = random.choice(keys)  #e.g. '+' 
    operation = ops[rand_key]  #e.g. op.add

    correct_result = operation(num1, num2)

    print ("What is {} {} {}?".format(num1, rand_key, num2))
    user_answer= int(input("Your answer: "))

    if user_answer != correct_result:
        print ("Incorrect. The right answer is {}".format(correct_result))
        return False
    else:
        print("Correct!")
        return True

username = input("What is your name? ")
print("Hi {}! Welcome to the Arithmetic quiz...".format(username))

correct_answers = 0
num_questions = 3

for i in range(num_questions):
    if test():
        correct_answers +=1


print("{}: You got {}/{} questions correct.".format(
    username, 
    correct_answers, 
    num_questions,
    #'question' if (correct_answers==1) else 'questions'
))