6 python快速上手

发布时间:2024年01月20日

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常见的数据类型:

  • int,整数类型(整形)
  • bool,布尔类型
  • str,字符串类型
  • list,列表类型
  • tuple,元组类型
  • dict,字典类型
  • set,集合类型
  • float,浮点类型(浮点型)

目标:掌握列表和元组数据类型的各种操作(知识点应用案例)。

课程概要:

  • list,列表类型,用于存储一些数据的容器(有序 & 可修改)。【80%】
  • tuple,元组类型,用于存储一些数据的容器(有序 & 不可修改)。【20%】

1.列表(list)

列表(list),是一个有序可变的容器,在里面可以存放多个不同类型的元素。

1.1 定义

user_list =  ["苍老师","有坂深雪","大桥未久"]
number_list = [98,88,666,12,-1]
data_list = [1,True,"Alex","宝强","贾乃亮"]
user_list = []
user_list.append("铁锤")
user_list.append(123)
user_list.append(True)
print(user_list) # ["铁锤",123,True]

不可变类型:字符串、布尔、整型(已最小,内部数据无法进行修改)

可变类型:列表(内部数据元素可以修改)

1.2 独有功能

Python中为所有的列表类型的数据提供了一批独有的功能。

在开始学习列表的独有功能之前,先来做一个字符串和列表的对比:

  • 字符串,不可变,即:创建好之后内部就无法修改。【独有功能都是新创建一份数据】

    name = "alex"
    data = name.upper()
    print(name)
    print(data)
    
  • 列表,可变,即:创建好之后内部元素可以修改。【独有功能基本上都是直接操作列表内部,不会创建新的一份数据】

    user_list = ["车子","妹子"]
    user_list.append("嫂子")
    
    print(user_list) # ["车子","妹子","嫂子"]
    

列表中的常见独有功能如下:

  1. 追加,在原列表中尾部追加值。

    data_list = []
    
    v1 = input("请输入姓名")
    data_list.append(v1)
    
    v2 = input("请输入姓名")
    data_list.append(v2)
    
    print(data_list) # ["alex","eric"]
    
    # 案例1
    user_list = []
    
    while True:
        user = input("请输入用户名(Q退出):")
        if user == "Q":
            break
        user_list.append(user)
        
    print(user_list) 
    
    # 案例2
    welcome = "欢迎使用NB游戏".center(30, '*')
    print(welcome)
    
    user_count = 0
    while True:
        count = input("请输入游戏人数:")
        if count.isdecimal():
            user_count = int(count)
            break
        else:
            print("输入格式错误,人数必须是数字。")
    
    
    message = "{}人参加游戏NB游戏。".format(user_count)
    print(message)
    
    
    user_name_list = []
    
    for i in range(1, user_count + 1):
        tips = "请输入玩家姓名({}/{}):".format(i, user_count)
        name = input(tips)
        user_name_list.append(name)
    
    print(user_name_list)
    
  2. 批量追加,将一个列表中的元素逐一添加另外一个列表。

    tools = ["搬砖","菜刀","榔头"]
    tools.extend( [11,22,33] ) # weapon中的值逐一追加到tools中
    print(tools) # ["搬砖","菜刀","榔头",11,22,33]
    
    tools = ["搬砖","菜刀","榔头"]
    weapon = ["AK47","M6"]
    #tools.extend(weapon) # weapon中的值逐一追加到tools中
    #print(tools) # ["搬砖","菜刀","榔头","AK47","M6"]
    
    weapon.extend(tools)
    print(tools) # ["搬砖","菜刀","榔头"]
    print(weapon) # ["AK47","M6","搬砖","菜刀","榔头"]
    
    # 等价于(扩展)
    weapon = ["AK47","M6"]
    for item in weapon:
        print(item)
    
    # 输出:
    #  AK47
    #  M6
    tools = ["搬砖","菜刀","榔头"]
    weapon = ["AK47","M6"]
    for item in weapon:
        tools.append(item)  
    print(tools) # ["搬砖","菜刀","榔头","AK47","M6"]
    
  3. 插入,在原列表的指定索引位置插入值

    user_list = ["苍老师","有坂深雪","大桥未久"]
    user_list.insert(0,"马蓉")
    user_list.insert(2,"李小璐")
    print(user_list)
    
    # 案例
    name_list = []
    while True:
        name = input("请输入购买火车票用户姓名(Q/q退出):")
        if name.upper() == "Q":
            break
        if name.startswith("刁"):
            name_list.insert(0, name)
        else:
            name_list.append(name)
    print(name_list)
    
  4. 在原列表中根据值删除(从左到右找到第一个删除)【慎用,里面没有会报错】

    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    user_list.remove("Alex")
    print(user_list)
    
    
    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    if "Alex" in user_list:
    	user_list.remove("Alex")
    print(user_list)
    
    
    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    while True:
        if "Alex" in user_list:
            user_list.remove("Alex")
    	else:
            break
    print(user_list)
    
    # 案例:自动抽奖程序
    import random
    
    data_list = ["iphone12", "二手充气女友", "大保健一次", "泰国5日游", "避孕套"]
    
    while data_list:
        name = input("自动抽奖程序,请输入自己的姓名:")
    
        # 随机从data_list抽取一个值出来
        value = random.choice(data_list) # "二手充气女友"
        print( "恭喜{},抽中{}.".format(name, value) )
        
        data_list.remove(value) # "二手充气女友"
    
  5. 在原列表中根据索引踢出某个元素(根据索引位置删除)

    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    #               0       1      2      3       4
    user_list.pop(1)
    print(user_list) #  ["王宝强","Alex","贾乃亮","Alex"]
    
    user_list.pop()
    print(user_list) # ["王宝强","Alex","贾乃亮"]
    
    item = user_list.pop(1)
    print(item) # "Alex"
    print(user_list) # ["王宝强","贾乃亮"]
    
    # 案例:排队买火车票
    
    # ["alex","李杰","eric","武沛齐","老妖","肝胆"]
    user_queue = []
    
    while True:
        name = input("北京~上海火车票,购买请输入姓名排队(Q退出):")
        if name == "Q":
            break
        user_queue.append(name)
    
    ticket_count = 3
    for i in range(ticket_count):
        username = user_queue.pop(0)
        message = "恭喜{},购买火车票成功。".format(username)
        print(message)
    
    # user_queue = ["武沛齐","老妖","肝胆"]
    faild_user = "、".join(user_queue) # "武沛齐、老妖、肝胆"
    faild_message = "非常抱歉,票已售完,以下几位用户请选择其他出行方式,名单:{}。".format(faild_user)
    print(faild_message)
    
  6. 清空原列表

    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    user_list.clear()
    print(user_list) # []
    
  7. 根据值获取索引(从左到右找到第一个删除)【慎用,找不到报错】

    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    #               0       1      2       3      4
    if "Alex" in user_list:
    	index = user_list.index("Alex")
    	print(index) # 2
    else:
        print("不存在")
    
  8. 列表元素排序

    # 数字排序
    num_list = [11, 22, 4, 5, 11, 99, 88]
    print(num_list)
    num_list.sort()  # 让num_list从小到大排序
    num_list.sort(reverse=True)  # # 让num_list从大到小排序
    print(num_list)
    
    
    # 字符串排序
    user_list = ["王宝强", "Ab陈羽凡", "Alex", "贾乃亮", "贾乃", "1"]
    #       [29579, 23453, 24378]
    #       [65, 98, 38472, 32701, 20961]
    #       [65, 108, 101, 120]
    #       [49]
    print(user_list)
    """
    sort的排序原理
        [ "x x x" ," x x x x x " ]
    """
    user_list.sort()
    print(user_list)
    

    注意:排序时内部元素无法进行比较时,程序会报错(尽量数据类型统一)。

  9. 反转原列表

    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    user_list.reverse()
    
    print(user_list)
    

1.3 公共功能

  1. 相加,两个列表相加获取生成一个新的列表。

    data = ["赵四","刘能"] + ["宋晓峰","范德彪"]
    print(data) # ["赵四","刘能","宋晓峰","范德彪"]
    
    v1 = ["赵四","刘能"]
    v2 = ["宋晓峰","范德彪"]
    v3 = v1 + v2
    print(v3) # ["赵四","刘能","宋晓峰","范德彪"]
    
  2. 相乘,列表*整型 将列表中的元素再创建N份并生成一个新的列表。

    data = ["赵四","刘能"] * 2
    print(data) # ["赵四","刘能","赵四","刘能"]
    
    v1 = ["赵四","刘能"]
    v2 = v1 * 2
    print(v1) # ["赵四","刘能"]
    print(v2) # ["赵四","刘能","赵四","刘能"]
    
  3. 运算符in包含
    由于列表内部是由多个元素组成,可以通过in来判断元素是否在列表中。

    user_list = ["狗子","二蛋","沙雕","alex"] 
    result = "alex" in user_list
    # result = "alex" not in user_list
    print(result) #  True
    
    if "alex" in user_list:
        print("在,把他删除")
        user_list.remove("alex")
    else:
        print("不在")
    
    user_list = ["狗子","二蛋","沙雕","alex"] 
    if "alex" in user_list:
        print("在,把他删除")
        user_list.remove("alex")
    else:
        print("不在")
    
    text = "打倒小日本"
    data = "日" in text
    
    # 案例
    user_list = ["狗子","二蛋","沙雕","alex"] 
    if "alex" in user_list:
        print("在,把他删除")
        user_list.remove("alex")
    else:
        print("不在")
    
    # 案例
    user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
    if "Alex" in user_list:
    	index = user_list.index("Alex")
    	user_list.pop(index)
    
    # 案例:敏感词替换
    text = input("请输入文本内容:") # 按时打发第三方科技爱普生豆腐啊;了深刻的房价破阿偶打飞机
    forbidden_list = ["草","欧美","日韩"]
    for item in forbidden_list:
        text = text.replace(item,"**")
    print(text)
    

    注意:列表检查元素是否存在时,是采用逐一比较的方式,效率会比较低。

  4. 获取长度

    user_list = ["范德彪","刘华强",'尼古拉斯赵四']
    print( len(user_list) )
    
  5. 索引,一个元素的操作

    # 读
    user_list = ["范德彪","刘华强",'尼古拉斯赵四']
    print( user_list[0] )
    print( user_list[2] )
    print( user_list[3] ) # 报错
    
    # 改
    user_list = ["范德彪","刘华强",'尼古拉斯赵四']
    user_list[0] = "武沛齐"
    print(user_list) # ["武沛齐","刘华强",'尼古拉斯赵四']
    
    # 删
    user_list = ["范德彪","刘华强",'尼古拉斯赵四']
    del user_list[1]
    
    user_list.remove("刘华强")
    ele = user_list.pop(1)
    

    注意:超出索引范围会报错。
    提示:由于字符串是不可变类型,所以他只有索引读的功能,而列表可以进行 读、改、删

  6. 切片,多个元素的操作(很少用)

    # 读
    user_list = ["范德彪","刘华强",'尼古拉斯赵四']
    
    print( user_list[0:2] ) # ["范德彪","刘华强"]
    print( user_list[1:] )
    print( user_list[:-1] )
    
    # 改
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    user_list[0:2] = [11, 22, 33, 44]
    print(user_list) # 输出 [11, 22, 33, 44, '尼古拉斯赵四']
    
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    user_list[2:] = [11, 22, 33, 44]
    print(user_list) # 输出 ['范德彪', '刘华强', 11, 22, 33, 44]
    
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    user_list[3:] = [11, 22, 33, 44]
    print(user_list) # 输出 ['范德彪', '刘华强', '尼古拉斯赵四', 11, 22, 33, 44]
    
    
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    user_list[10000:] = [11, 22, 33, 44]
    print(user_list) # 输出 ['范德彪', '刘华强', '尼古拉斯赵四', 11, 22, 33, 44]
    
    
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    user_list[-10000:1] = [11, 22, 33, 44]
    print(user_list) # 输出 [11, 22, 33, 44, '刘华强', '尼古拉斯赵四']
    
    # 删
    user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
    del user_list[1:]
    print(user_list) # 输出 ['范德彪']
    
  7. 步长

    user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    #              0        1        2          3       4
    print( user_list[1:4:2] )
    print( user_list[0::2] )
    print( user_list[1::2] )
    print( user_list[4:1:-1] )
    
    # 案例:实现列表的翻转
    user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    new_data = user_list[::-1]
    print(new_data)
    
    
    data_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    data_list.reverse()
    print(data_list)
    
    # 给你一个字符串请实现字符串的翻转?
    name = "武沛齐"
    name[::-1]
    
  8. for循环

    user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    for item in user_list:
    	print(item)
    
    user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    
    for index in range( len(user_list) ):
        item = user_index[index]
        print(item)
    

    切记,循环的过程中对数据进行删除会踩坑【面试题】。

    # 错误方式, 有坑,结果不是你想要的。
    
    user_list = ["刘的话", "范德彪", "刘华强", '刘尼古拉斯赵四', "宋小宝", "刘能"]
    for item in user_list:
        if item.startswith("刘"):
            user_list.remove(item)
            
    print(user_list)
    
    
    
    # 正确方式,倒着删除。
    user_list = ["刘的话", "范德彪", "刘华强", '刘尼古拉斯赵四', "宋小宝", "刘能"]
    for index in range(len(user_list) - 1, -1, -1):
        item = user_list[index]
        if item.startswith("刘"):
            user_list.remove(item)
    print(user_list)
    

1.4 转换

  • int、bool无法转换成列表

  • str

    name = "武沛齐"
    
    data = list(name)  # ["武","沛","齐"]
    print(data)
    
  • 超前

    v1 = (11,22,33,44) # 元组
    vv1 = list(v1)     # 列表 [11,22,33,44]
    
    v2 = {"alex","eric","dsb"} # 集合
    vv2 = list(v2) # 列表 ["alex","eric","dsb"]
    

1.5. 其他

1.5.1 嵌套

列表属于容器,内部可以存放各种数据,所以他也支持列表的嵌套,如:

data = [ "谢广坤",["海燕","赵本山"],True,[11,22,[999,123],33,44],"宋小宝" ]

对于嵌套的值,可以根据之前学习的索引知识点来进行学习,例如:

data = [ "谢广坤",["海燕","赵本山"],True,[11,22,33,44],"宋小宝" ]

print( data[0] ) # "谢广坤"
print( data[1] ) # ["海燕","赵本山"]
print( data[0][2] ) # "坤"
print( data[1][-1] ) # "赵本山"

data.append(666)
print(data) # [ "谢广坤",["海燕","赵本山"],True,[11,22,33,44],"宋小宝",666]

data[1].append("谢大脚")
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,22,33,44],"宋小宝",666 ]


del data[-2]
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,22,33,44],666 ]


data[-2][1] = "alex"
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,"alex",33,44],666 ]


data[1][0:2] = [999,666]
print(data) # [ "谢广坤",[999,666,"谢大脚"],True,[11,"alex",33,44],666 ]
# 创建用户列表
#    用户列表应该长: [ ["alex","123"],["eric","666"] ]

# user_list = [["alex","123"],["eric","666"],]
# user_list.append(["alex","123"])
# user_list.append(["eric","666"])


user_list = []
while True:
    user = input("请输入用户名:")
    pwd = input("请输入密码:")

    data = []
    data.append(user)
    data.append(pwd)
    
    user_list.append(data)
user_list = []
while True:
    user = input("请输入用户名(Q退出):")
    if user == "Q":
        break
    pwd = input("请输入密码:")
    data = [user,pwd]
    user_list.append(data)

print(user_list)

2.元组

列表(list),是一个有序可变的容器,在里面可以存放多个不同类型的元素。

元组(tuple),是一个有序不可变的容器,在里面可以存放多个不同类型的元素。

如何体现不可变呢?
记住一句话:《“我儿子永远不能换成是别人,但我儿子可以长大”》

2.1 定义

v1 = (11,22,33)
v2 = ("李杰","Alex")
v3 = (True,123,"Alex",[11,22,33,44])

# 建议:议在元组的最后多加一个逗v3 = ("李杰","Alex",)
d1 = (1)  # 1
d2 = (1,) # (1,)

d3 = (1,2)
d4 = (1,2)

注意:建议在元组的最后多加一个逗号,用于标识他是一个元组。

# 面试题
1. 比较值 v1 = (1) 和 v2 = 1 和 v3 = (1,) 有什么区别?
2. 比较值 v1 = ( (1),(2),(3) ) 和 v2 = ( (1,) , (2,) , (3,),) 有什么区别?
              (1,2,3)

2.2 独有功能

2.3 公共功能

  1. 相加,两个列表相加获取生成一个新的列表。

    data = ("赵四","刘能") + ("宋晓峰","范德彪")
    print(data) # ("赵四","刘能","宋晓峰","范德彪")
    
    v1 = ("赵四","刘能")
    v2 = ("宋晓峰","范德彪")
    v3 = v1 + v2
    print(v3) # ("赵四","刘能","宋晓峰","范德彪")
    
  2. 相乘,列表*整型 将列表中的元素再创建N份并生成一个新的列表。

    data = ("赵四","刘能") * 2
    print(data) # ("赵四","刘能","赵四","刘能")
    
    v1 = ("赵四","刘能")
    v2 = v1 * 2
    print(v1) # ("赵四","刘能")
    print(v2) # ("赵四","刘能","赵四","刘能")
    
  3. 获取长度

    user_list = ("范德彪","刘华强",'尼古拉斯赵四',)
    print( len(user_list) )
    
  4. 索引

    user_list = ("范德彪","刘华强",'尼古拉斯赵四',)
    print( user_list[0] )
    print( user_list[2] )
    print( user_list[3] )
    
  5. 切片

    user_list = ("范德彪","刘华强",'尼古拉斯赵四',)
    print( user_list[0:2] )
    print( user_list[1:] )
    print( user_list[:-1] )
    
  6. 步长

    user_list = ("范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能")
    print( user_list[1:4:2] )
    print( user_list[0::2] )
    print( user_list[1::2] )
    print( user_list[4:1:-1] )
    
    # 字符串 & 元组。
    user_list = ("范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能")
    data = user_list[::-1]
    
    # 列表
    user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
    data = user_list[::-1]
    
    user_list.reverse()
    print(user_list)
    
  7. for循环

    user_list = ("范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能")
    for item in user_list:
    	print(item)
    
    user_list = ("范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能")
    for item in user_list:
     if item == '刘华强':
    	 continue
     print(name)
    

    目前:只有 str、list、tuple 可以被for循环。 “xxx” [11,22,33] (111,22,33)

    # len + range + for + 索引
    user_list = ("范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能")
    for index in range(len(user_list)):
        item = user_list[index]
        print(item)
    

2.4 转换

其他类型转换为元组,使用tuple(其他类型),目前只有字符串和列表可以转换为元组。

data = tuple(其他)

# str / list 
name = "武沛齐"
data = tuple(name)
print(data) # 输出 ("武","沛","齐")
name = ["武沛齐",18,"pythonav"]
data = tuple(name)
print(data) # 输出 ("武沛齐",18,"pythonav")

2.5 其他

2.5.1 嵌套

由于元组和列表都可以充当容器,他们内部可以放很多元素,并且也支持元素内的各种嵌套。

tu = ( '今天姐姐不在家', '姐夫和小姨子在客厅聊天', ('姐夫问小姨子税后多少钱','小姨子低声说道说和姐夫还提钱') )
tu1 = tu[0]
tu2 = tu[1]
tu3 = tu[2][0]
tu4 = tu[2][1]
tu5 = tu[2][1][3]

print(tu1) # 今天姐姐不在家
print(tu2) # 姐夫和小姨子在客厅聊天
print(tu3) # 姐夫问小姨子税后多少钱
print(tu4) # 小姨子低声说道说和姐夫还提钱

练习题1:判断是否可以实现,如果可以请写代码实现。

li = ["alex", [11,22,(88,99,100,),33],  "WuSir",  ("ritian", "barry",),  "wenzhou"]
#        0               1                 2                3                4

# 1.请将 "WuSir" 修改成 "武沛齐"
li[2] = "武沛齐"
index = li.index("Wusir")
li[index] = "武沛齐"

# 2.请将 ("ritian", "barry",) 修改为 ['日天','日地']
li[3] = ['日天','日地']

# 3.请将 88 修改为 87
li[1][2][0] = 87 # (报错,)

# 4.请将 "wenzhou" 删除,然后再在列表第0个索引位置插入 "周周"
# li.remove("wenzhou")
# del li[-1]
li.insert(0,"周周")

练习题2:记住一句话:《“我儿子永远不能换成是别人,但我儿子可以长大”》

data = ("123",666,[11,22,33], ("alex","李杰",[999,666,(5,6,7)]) )

# 1.将 “123” 替换成 9   报错

# 2.将 [11,22,33] 换成 "武沛齐"    报错

# 3.将 11 换成 99
data[2][0] = 99
print(data)  # ("123",666,[99,22,33], ("alex","李杰",[999,666,(5,6,7)]) )

# 4.在列表 [11,22,33] 追加一个44
data[2].append(44)
print(data) # ("123",666,[11,22,33,44], ("alex","李杰",[999,666,(5,6,7)]) )

练习题3:动态的创建用户并添加到用户列表中。

# 创建用户 5个
# user_list = [] # 用户信息
user_list = [ ("alex","132"),("admin","123"),("eric","123") ]

while True:
    user = input("请输入用户名:")
    if user == "Q":
        brek
    pwd = input("请输入密码:")
    item = (user,pwd,)
    user_list.append(item)
    
# 实现:用户登录案例
print("登录程序")
username = input("请输入用户名:")
password = input("请输入密码:")

is_success = False

for item in user_list:
    # item = ("alex","132")   ("admin","123")    ("eric","123")
    if username == item[0] and password == item[1]:
        is_success = True
        break

if is_success:
    print("登录成功")
else:
    print("登录失败")

总结

  1. 概述
    • 列表,以后写程序会用的非常多,要多些多练。
    • 元组,以后写程序用的不是很多,主要以了解其特殊和用法为主。
  2. 列表和元组的区别。
  3. 可变类型和不可变类型。
  4. 列表独有功能 & 公共功能(不用特地去记,多做题目去用,以后每天都会有相关的练习题)。
  5. 列表和元组等数据的嵌套
  6. 元组中 (1) 和 (1,) 的区别。
  7. 元组的元素不能被替换,但元组的元素如果是可变类型,可变类型内部是可以修改的。
文章来源:https://blog.csdn.net/hellow_xqs/article/details/135707742
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