• 9道python基础练习题


    1. 3位整数逆序

    num = input("请输入一个三位整数:")
    
    print(num[::-1])
    

    2. if - else 练习

    sex = input('请输入您的性别(F 或 M): ')
    age = int(input("请输入您的年龄: "))
    
    if sex == "M":
        if age < 30:
            print('young')
        elif age <= 36:
            print('marriageable age')
        else:
            print('old')
    
    elif sex == 'F':
        if age < 25:
            print('young')
        elif age <= 30:
            print('marriageable age')
        else:
            print('old')
    
    else:
        print('wrong')
    

    3. if-else 和 数学计算 练习

    #Python学习交流群:778463939
    
    my_str = input("What's the temperature? ")
    
    if my_str[-1] in ['F', 'f']:
        C = round((eval(my_str[0:-1]) - 32) / 1.8, 1)
    
        print(f"The converted temperature is {C}C.")
    
    
    elif my_str[-1] in ['C', 'c']:
        F = round(1.8 * eval(my_str[0:-1]) + 32, 1)
    
        print(f"The converted temperature is {F}F.")
    
    else:
        print("input error my dear.")
    

    4. 循环: 文件读写

    with open("movie.txt") as f_in:
        with open("out.txt") as f_out:
            for line in f_in:
                # 假设每行数据, 分割符是 ','
                line_list = line.split(',')
                # 时长 Lasting 是最后一列
                if line_list[-1] < 90:
                    # 将该行序号写到 out.txt
                    f_out.write(str(line_list[0]))
    

    5.循环练习: 亲密数

    #Python学习交流群:778463939
    
    x = int(input("请输入一个正整数: "))
    
    for a in range(2, x):
        b = 0
        for i in range(1, a):
            if a % i == 0:
                b += i
        r = 0
        for j in range(1, b):
            if b % j == 0:
                r += j
        if r == a and a < b:
            print(a, b)
    

    6.循环: 逻辑判断

    n = int(input('请输入最大兵力人数: '))
    
    for i in range(n + 1):
        if (i % 3 == 2) and (i % 5 == 1) and (i % 7 == 0):
            print(i, end=' ')
    

    7.列表推导式

    num = int(input("请输入一个 1-100 间的整数: "))
    
    print([i for i in range(1, num + 1) if i % 2 != 0])
    

    8.正则表达式

    # 匹配: 首字母为 '数字或下划线, 其余字母为 字母,数字,下划线'
    
    import re
    
    my_str = input("请输入您将要注册的用户名: ")
    
    ret = re.match(r"[a-z_]?[a-zds_]*", my_str)
    
    print(ret.group())
    print(True) if ret else print(False)
    

    9.字典按值排序

    import operator
    
    int(input("输入您要处理的整数个数: "))
    num_lst = list(map(int, input("请在一行输入, 两两间用 空格 隔开").split()))
    
    my_dict = {}
    for num in num_lst:
        if num not in my_dict:
            my_dict[num] = 1
        else:
            my_dict[num] += 1
    
    items = sorted(my_dict.items(), key=operator.itemgetter(1), reverse=True)
    for i, j in items:
        print(str(i) + ' ' + str(j))
    
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  • 原文地址:https://www.cnblogs.com/xxpythonxx/p/14076091.html
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