Python学习之路（十）：实例整理

1.while

count = 1
while count <= 3:
    print(count)
    user = input('请输入您的姓名')
    psw = input('请输入您的密码')
    if user == 'newboy' and psw == 'pushu666':
         print('登陆成功')
         break
    else:
        print('登陆失败')
    if count == 3:
        choice = input('请输入是否需要继续(Y/N):')
        if choice == 'Y':
            count = 1
            continue
        elif choice == 'N':
             break
        else:
             print('输入错误')
        break
    count = count + 1

count = 1
while count <= 3:
    print(count)
    user = input('请输入您的用户名')
    psw = input('请输入您的密码')
    if user == 'newboy' and psw == 'pushu666':
        print('登陆成功')
        break
    else:
        time = 3 - count
        template = '密码或用户名错误，您还剩余%s次机会。' %(time,)
        print(template)
    count = count + 1

count = 2
while count >= 0:
    user = input('请输入您的用户名')
    psw = input('请输入您的密码')
    if user == 'newboy' and psw == 'pushu666':
        print('欢迎登陆')
        break
    template = '密码或用户名错误，您还剩余%s次机会。' % (count,)
    print(template)
    count -= 1
else:

ount = 1
while count <= 10:
    fen = int(input('请第%s号评委打分：' % (count,)))
    if fen > 10 or fen <0:
        print('请重新输入！')
        continue
    else:
        print('第%s为评委打分为:%s'% (count, fen,))
    count += 1

2.数据类型相关

# 输出所有键值，并且根据输入的键输出相应的值：
info = {'name': '卡戴珊', 'age': 18, 'gender': '女', 'hobby': '同志'}
for k, v in info.items():
    print(k, v)
    key = input('请输入属性：')
print(info[key])

# 给出一个空字典，在字典中加入相应的键值k1=1,k2=2,k3=3.
info = {}
info['k1'] = '1'  # 此时加入的k1的值为字符串，而k2,k3为数字
info['k2'] = 2
info['k3'] = 3
print(info)

# 给出一个空字典，在字典中加入用户输入的key和value：
info = {}
k = 0 
while k <= 3:
    key = input('请输入key:')
    value = input('请输入value:')
    info[key] = value
    k = k + 1
print(info)

# 请用代码实现 'k1|v1, k2|v2, k3|v3, k4|v4' ---> {'k1':'v1', 'k2':'v2', 'k3':'v3', 'k4':'v4'}

info = {}
message = 'k1|v1,k2|v2,k3|v3,k4|v4'
for i in message.split(','):
    v1, v2 = i.split('|')
    info[v1] = v2
    print(info)

# 构建用户列表，然后让用户进行登陆验证
"""
user_list = []
while True:
    k = input('请输入用户名：')
    if k == 'N':
        break
    v = input('请输入密码：')
    info = {}
    info['user'] = k
    info['psw'] = v
    user_list.append(info)
print(user_list)
username = input('请输入登陆名：')
password = input('请输入用户密码：')
message = '登陆失败'
for items in user_list:
    if items['user'] == username and items['psw'] == password:
        message = '登陆成功'
        break
print(message)

#  将11,22,33,44,55,66,77,88,99,111中大于66的数字存放在字典键k1下，其余存在k2下
"""
li = [11, 22, 33, 44, 5, 66, 77, 88, 99, 111]
dic = {'k1':[], 'k2':[]}
for i in li:
    if i == 66:
        continue
    elif i > 60:
        dic.setdefault('k1').append(i) #如果default中没有value就只进行查询操作
    else:
        dic.setdefault('k2').append(i)
print(dic)

# 购物车
goods = [{'name': '电脑', 'price':1999},
         {'name': '鼠标', 'price':10},
         {'name': '游艇', 'price':20},
         {'name': '美女', 'price':998}, ]
while 1:
    for i in goods:
        print(goods.index(i) + 1, i['name'], i['price'])
    str_input = input('请输入您要选择的商品序号，输入Q/q退出：')
    if str_input.isdigit() and 0 < int(str_input) < len(goods):
        i_index = int(str_input) - 1
        print(goods[i_index]['name'], goods[i_index]['price'])
    elif str_input.upper() == 'Q':
        break
    else:
        print('输入错误，请重新输入！')

# 水仙花数
num = input('请输入一个数：')
s = 0
for c in num:
    s = int(c) ** 3 + s
if int(num) == s:
    print('水仙花数')
else:
    print('不是，请重新输入')

# 排序(不用sort):冒泡排序
lst = [1, 3, 6, 8, 5, 11]
count = 0
while count < len(lst):
    i = 0
    while i < len(lst) - 1:
        if lst[i] > lst[i+1]:
            lst[i], lst[i+1] = lst[i+1], lst[i]
        i = i+1
    count += 1
print(lst)

3.函数

# 打印索引为基数的元素
def func(lst):
    result = []
    for i in range(len(lst)):
        if i % 2 == 1:
            result.append(lst[i])
    return result


ret = func(["皇阿玛", "纪晓岚", "河身", "小六子"])
print(ret)

lst = ["皇阿玛", "纪晓岚", "河身", "小六子"]
def func(lst):
    return lst[1::2]
print(func(lst))

 

# 计算字符串中数字、字母以及空格数量
def func(s):
    shuzi = 0
    zimu = 0
    kongge = 0
    qita = 0
    for i in s:
        if i.isdigit():
            shuzi += 1
        elif i.isalpha():
            zimu += 1
        elif i == ' ':
            kongge += 1
        else:
            qita += 1
    return shuzi, zimu, kongge, qita
print(func(s = 'dsafwef  wef907987fa'))

# 比较大小
def func(a, b):
    return a if a > b else b
print(func(10, 90))

# 将字典中值的长度大于2的键值对装入新字典
def func(dic):
    new_dic = {}
    for k, v in dic.items():
        if len(v) > 2:
            s = v[0:2]
            new_dic[k] = s
        else:
            new_dic[k] = v
    return new_dic
print(func({'jay':'周杰伦', '潘婷':'洗发水', '赌神': '周润发'}))

 

4.文件

# 在指定文件中写入信息
def func(name, gender, age, edu):
    with open("student_msg", mode="a", encoding='utf-8') as f:
        f.write(name+"_"+gender+"_"+age+"_"+edu+"\n")
        return name, gender, age, edu
name = input("请输入姓名：")
gender = input("请输入性别：")
age = input("请输入年龄：")
edu = input("请输入学历：")
print(func(name, gender, age, edu))

def func(name, age, edu, gender="男"):
    with open("student_msg", mode="a", encoding='utf-8') as f:
        f.write(name+"_"+gender+"_"+age+"_"+edu+"\n")
        return name, gender, age, edu
while 1:
    name = input("请输入姓名：")
    gender = input("请输入性别：")
    age = input("请输入年龄：")
    edu = input("请输入学历：")
    if gender == "":
        print(func(name, age, edu))
    else:
        print(func(name, age, edu, gender))