Python基础语法文章导航:
目录
一.列表
1.定义
2.独有功能
(1)append()
(2)extend()
(3)insert()
(4)remove()
(5)pop()
(6)clear()
(7)index()
(8)sort()
(9)reverse()
3. 公共功能
(1)相加
(2)相乘
(3)运算符in包含
(4)获取长度
(5)索引
(6)切片
(7)步长
(8)for循环
4. 数据类型之间的转换
5. 列表嵌套
二.元组
1.定义
2.独有功能
3.公共功能
(2)相乘
(3)获取长度
(4)索引
(5)切片
(6)步长
(7)for循环
4. 数据类型之间的转换
5.元组嵌套
列表(list),是一个有序且可变的容器,在里面可以存放多个不同类型的元素。
data_list = [1,True,"Alex","宝强","贾乃亮"]
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"]
append():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) # ["王力宏","张韶涵"]
#案例
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)
extend():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]
weapon = ["AK47","M6"]
tools.extend(weapon)
print(tools) # ["搬砖","菜刀","榔头","AK47","M6"]
#拓展 extend()=for循环+append()
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"]
insert():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) #['马蓉', '苍老师', '李小璐', '有坂深雪', '大桥未久']
remove():在原列表中根据值删除(从左到右找到的第一个删除;如果没有值的话会报错,使用时要小心)
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)
pop():根据索引位置删除值
user_list = ["王宝强","陈羽凡","lily","贾乃亮","lily"]
# 0 1 2 3 4
user_list.pop(1)
print(user_list) # ["王宝强","lily","贾乃亮","lily"]
user_list.pop() #删除列表最后一个索引的值
print(user_list) # ["王宝强","lily","贾乃亮"]
item = user_list.pop(1)
print(item) # "lily"
print(user_list) # ["王宝强","贾乃亮"]
clear(): 清空原列表
user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
user_list.clear()
print(user_list) # []
index():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")
sort():排序时应尽量保持列表中的各元素的数据类型统一,否侧当内部元素无法比较时,程序会报错。
# 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)
reverse():反转原列表
user_list = ["王宝强","陈羽凡","lily","贾乃亮","lily"]
user_list.reverse()
print(user_list) #['lily', '贾乃亮', 'lily', '陈羽凡', '王宝强']
多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"]+["1111","222"]
print(data) # ['赵四', '刘能', '宋晓峰', '范德彪', '1111', '222']
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"]
列表*整型N: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"]
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。注意:用in检查列表元素是否存在时,是采用逐一比较的方式,效率会比较低。
# 案例
user_list = ["狗子","二蛋","三毛","图图"]
if "alex" in user_list:
print("在,把他删除")
user_list.remove("三毛")
else:
print("不在")
user_list = ["范德彪","刘华强",'尼古拉斯赵四']
print( len(user_list) ) #3
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
# 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]
#或者 user_list.remove("刘华强")
#或者 ele = user_list.pop(1)
# 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:] ) #['刘华强', '尼古拉斯赵四']
print( user_list[:-1] ) #['范德彪', '刘华强']
# 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']
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] )
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)
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)
# 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)
int、bool无法转换成列表
str
name = "武沛齐"
data = list(name) # ["武","沛","齐"]
print(data)
元组
v1 = (11,22,33,44) # 元组
vv1 = list(v1) # 列表 [11,22,33,44]
集合
v2 = {"alex","eric","dsb"} # 集合
vv2 = list(v2) # 列表 ["alex","eric","dsb"]
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 ]
列表(list),是一个有序且可变的容器,在里面可以存放多个不同类型的元素。
元组(tuple),是一个有序且不可变的容器,在里面可以存放多个不同类型的元素。
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。
v1 = (11,22,33)
v2 = ("李杰","Alex")
v3 = (True,123,"Alex",[11,22,33,44])
d1 = (1) # 1
d2 = (1,) # (1,)
无
(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")
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")
user_list = ("范德彪","刘华强",'尼古拉斯赵四',)
print( len(user_list) )
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] )
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] )
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)
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)
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。
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")
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。 元组有序且不可变。
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)]) )