小学数学运算题出题程序

需求

朋友担心小孩暑假玩疯了，让我弄点小学一年级数学题给小孩做，要求：

1. 就是简单的口算式子
2. 可以打印成 A4 纸
3. 有答案

根据要求，我觉得最简单的办法，就是生成一个内容用 tab 分隔开的 txt 文件，然后手工复制到排版好的 Excel 文件里面直接打印即可。

原始代码

#coding: utf-8
"""本代码来自第一感觉，使用函数实现。添加问题类型时，直接修改 main() 的 question_list 语句即可
"""
import random

def question_1():
    """生成 100 以内退位减法"""
    minuend = random.randint(11,98)
    units = minuend % 10
    while units==9 :
        minuend = random.randint(11,98)
        units = minuend % 10
    subtrahend = random.randint(units+1,9)
    answer = minuend - subtrahend
    return ("%d - %d = " % (minuend, subtrahend), str(answer))

def question_2():
    """生成两位数加法"""
    num1 = random.randint(10, 99)
    num2 = random.randint(10, 99)
    answer = num1 + num2
    return ('%d + %d =' % (num1, num2), str(answer))

def question_3():
    """生成两位数减两位数"""
    minuend = random.randint(11,99)
    subtrahend = random.randint(10, minuend)
    answer = minuend - subtrahend
    return ("%d - %d = " % (minuend, subtrahend), str(answer))


def write_it(questions, answers, output_file):
    format_items(questions)
    format_items(answers)

    f = open(output_file, 'w')
    f.write("".join(questions))
    f.write("\n\n\n")
    f.write("".join(answers))
    f.close()

def format_items(items, number_per_line = 4):
    """用换行、tab 美化化输出结果，方便之后导入 excel"""
    for i,a in enumerate(items):
        if i % number_per_line == number_per_line - 1:
            items[i] = a + "\n"
        else:
            items[i] = a + "\t"

def main(output_file, question_type = 1):
    """question_type取值：1 到 3 """
    questions = []
    answers = []
    question_generator = [question_1, question_2, question_3]
    for x in range(80):
        question, answer = question_list[question_type - 1]()
        print( question)
        questions.append(question)
        answers.append(answer)

    print("now write it")
    write_it(questions, answers, output_file)

if __name__ == '__main__':
    output_file = "out.txt"
    main(output_file)

refactoring

引入 with 语句处理文件

以便在发生异常的时候自动关闭资源。将

f = open(output_file, 'w')
f.write("".join(questions))
f.write("\n\n\n")
f.write("".join(answers))
f.close()

改为

with open(output_file, 'w') as f:
    f.write("".join(questions))
    f.write("\n\n\n")
    f.write("".join(answers))

改成混合出题

单一类型题目指定生成，不如直接改成混合生成各类题型，并可以指定各种题型出现的概率。这可以直接利用 python 的 random.choices() 函数实现，请注意该函数的返回值是个 list ，main() 函数修改如下：

def main(output_file, number = 80):
    ...
    question_generator = [question_1, question_2, question_3]
    for x in range(number):
        which = random.choices([1,2,3], [0.2, 0.4, 0.4])[0] # 各类型题目概率
        question, answer = question_generator[which-1]()
        ...

最终成果

最后，给每个题目添加序号，以便打印出来的题目可以快速找到答案。完整最终代码如下：

#coding: utf-8
"""本代码实现小学一年级数学题目（主要是100以内加减法）的自动出题
"""
# 下一步计划：
#   - 添加网络框架（比如 flask），实现在线测试网站
#       - 允许选择难度、题型
#       - 自动汇总错题
#       - 需要登录，以便记录每个人自己的练习情况

import random

def question_1():
    """生成 100 以内退位减法"""
    minuend = random.randint(11,98)
    units = minuend % 10
    while units==9 :
        minuend = random.randint(11,98)
        units = minuend % 10
    subtrahend = random.randint(units+1,9)
    answer = minuend - subtrahend
    return ("%d - %d = " % (minuend, subtrahend), str(answer))

def question_2():
    """生成两位数加法"""
    num1 = random.randint(10, 99)
    num2 = random.randint(10, 99)
    answer = num1 + num2
    return ('%d + %d =' % (num1, num2), str(answer))

def question_3():
    """生成两位数减两位数"""
    minuend = random.randint(11,99)
    subtrahend = random.randint(10, minuend)
    answer = minuend - subtrahend
    return ("%d - %d = " % (minuend, subtrahend), str(answer))


def write_it(questions, answers, output_file):
    format_items(questions)
    format_items(answers)

    with open(output_file, 'w') as f:
        f.write("".join(questions))
        f.write("\n\n\n")
        f.write("".join(answers))

def format_items(items, number_per_line = 4):
    """用换行、tab 美化化输出结果，并添加序号，方便之后导入 excel"""
    for i,a in enumerate(items, start=1):
        if i % number_per_line == 0:
            items[i-1] = str(i) + ".\t" + a + "\n"
        else:
            items[i-1] = str(i) + ".\t" + a + "\t"

def main(output_file, number = 80):
    """主函数"""
    questions = []
    answers = []
    question_generator = [question_1, question_2, question_3]
    for x in range(number):
        which = random.choices([1,2,3], [0.2, 0.4, 0.4])[0] # 各类型题目概率
        question, answer = question_generator[which-1]()
        print( question)
        questions.append(question)
        answers.append(answer)

    print("now write it")
    write_it(questions, answers, output_file)

if __name__ == '__main__':
    output_file = "out.txt"
    main(output_file, number=800)