python 语法
列表# 第一种列表定义方法
# list1=["dcs","xiao03","10086",["10010","xiaozhang"]]
# print(list1)
# print(type(list1))
# 第二种列表定义方法
# str1="xian03"#定义字符串
# list1=list(str1)
# print(list1)
# 1.列表常用函数和用法
# 索引赋值
# list1=["dcs","xian03",10086,["10010","xiaozhang"]]
# list1="xiaoshuai"#把dcs替换xiaoshuai
# print(list1)
# 切片赋值
# list1=["dcs","xian03",10086,["10010","xiaozhang"]]
# list1 = "hello"
# print(list1)
# append():添加元素，把列表元素添加最末尾端
# list1=["xiaozhang","dcs","xian03","10010"]
# list1.append("10086")
# list1.append(6000)
# list1.append("中国")
# print(list1)
# insert:在索引前面位置插入元素
# list1=["xiaozhang","dcs","xian03","10010"]
# list1.insert(2,"xiaoshuai")
# list1.insert(2,6000)
# list1.insert(3,["china"])
# print(list1)
# extend:连接两个列表
# 列表连接
# list1=["name","age","xiaozhang"]
# list2=["hello","dcs","18"]
# list1.extend((list2))
# print(list1)
# 列表与字符串拼接
# list1=["name","age","xiaozhang"]
# list2="dcs"
# list1.extend(list2)
# print(list1)
# 列表与整数拼接
# list1=["name","age","xiaozhang"]
# int1=12456
# list1.extend(int1)
# print(list1) #报错不能拼接
# remove:根据元素移除
# list1=["xiaozhang","dcs","xian03",10010]
# list1.remove("dcs")
# print(list1)
# # 列表有重复元素，只会移除最前面一个
# list1=["xiaozhang","dcs","xian03",10010,10010]
# list1.remove(10010)
# list1.remove(10010) #一次删不完再删除一次
# print(list1)
# # del:根据索引进行删除关键字
# list1=["xiaozhang","dcs","xian03",10010,10010]
# del list1
# print(list1)
# pop:删除列表元素默认删除列表最后一个
# list1=["xiaozhang","dcs","xian03",10010]
# # print(list1.pop()) # 默认删除最后一个
# # print(list1.pop(2)) #指定删除一个
# print(list1)
# 在列表中用切片进行反转
# list1=["xiaozhang","dcs","xian03",10010]
# # # print(list1[ : : -1])
# # # 用reverse函数列表进行反转
# list1.reverse()
# print(list1)#66
# 列表排序
# sort():对列表排序(只针对全部为int、全部为str数据类型的元素进行排序，不能混合) 仅仅只是对列表进行排序的动作
list1=["xiaozhang","dcs","xian03","10010"]
list1.sort()#默认升序排序，根据ascii码排序，数字0—9>A-Z>a-z
print(list1)
list1.sort(reverse=True) #进行降序排列，用sort()函数中reverse参数等于true
print(list1)
# sorted:这个函数对列表进行排列，排序完后，(会生成一个排序后新的列表)(默认升序排序)
list1=[1,3,6,2,5]
list2=sort1·ed(list1) #sorted(list1)函数给list1排序后生成一个排序后新列表
print(list2)
print(list1)
list3 = sorted(list1,reverse=True)#降序需要加添加一个reverse=true参数
print(list3)# 元组
# 第一种定义元组
# tuple1=("dcs","xiaozhang",12,["hello","china"])
# print(tuple1)
# # 第二种创建元组的方法
# list1=["dcs","xiaozhang",12,["hello","china"]]
# tuple1=tuple(list1)
# print(tuple1)
# # 当元组中，元组的个数为1的时候，需要在最后加一个英文逗号
# tuple1=("xiaozhang",)
# print(tuple1)
# print(type(tuple1))
# 在元祖中使用索引对元组取值
# tuple1=("dcs","xiaozhang",12,["hello","china"])
# print(tuple1)
# tuple1
# tuple1.insert(0,"xian03")
# del tuple1
# print(tuple1)
# 间接的修改元素，先把元祖转换成列表，在列表进行修改，修改后再转换成元祖
# tuple1 = ("dcs", "xiaozhang", 12, ["hello", "china"])
# list1=list(tuple1)
# list1="xian03"
# tuple2=tuple(list1)
# print(tuple2)
# 元组可以改变？
# 当
tuple1 = ("dcs", "xiaozhang", 12, ["hello", "china"])
tuple1[3][1]="chinese"
print(tuple1)
# 可迭代
tuple1 = ("dcs", "xiaozhang", 12, ["hello", "china"])
for a in tuple1:
print(a)# 字典
# dict={ }
# 第一种定义字典的方法
# dict1={"name":"xiaozhang","age":"18"}
# print(dict1)
# print(type(dict1))
# 第二种定义字典方法
# list1=(["name","xiaozhang"],["age","18"])
# dict1=dict(list1)
# print(dict1)
# print(type(dict1))
# 给字典添加一个键值对
# dict1={"name":"xiaozhang","age":"18"}
# dict1["sex"]="man"
# print(dict1)
# 取出字典中的键值对====通过for循环遍历字典中键(key)
# dict1={"name":"xiaozhang","age":"18"}
# for i in dict1.keys():
# print(i)
# 不加修饰函数遍历字典
# for i in dict1:
# print(i)
# 取出字典中的值=====遍历取值，取字典中所有
# dict1={"name":"xiaozhang","age":"18"}
# for i in dict1.values():
# print(i)
# 需要取出字典中特点的值====需要用到键来取值
# dict1={"name":"xiaozhang","age":"18"}
# print(dict1["name"])
# print(dict1["age"])
# setdefault()函数:给字典添加键值对
# dict1={"name":"xiaozhang","age":"18"}
# dict1.setdefault("sex","men")
# dict1.setdefault("age","19")
# dict1.setdefault("class")
# print(dict1)
# del:删除字典
#dict1={"name":"xiaozhang","age":"18"}
# del dict1 #删除字典他通过关键字del删除
# print(dict1) #NameError: name 'dict1' is not defined已经删除了不存在会报错
# 根据键(key)用del来删除键值对
# dict1={"name":"xiaozhang","age":"18"}
# del dict1["name"] #通过删除字典中的键，从而删除整个键值对
# print(dict1)
# 同时取字典中的键与值
# dict1={"name":"xiaozhang","age":"18"}
# 第一种同时取字典中的键与值的方法
# for i in dict1:
# print(i,dict1)
# # 第二种同时取字典中的键与值的方法
# for k,v in dict1.items():
# print(k,v)
# dict1={"name":"xiaozhang","age":"18"}
# # pop()函数：删除指定键，并返回删除值，通过key来删除值
# dict1={"name":"xiaozhang","age":"18"}
# print(dict1.pop("name"))
# print(dict1)
# clear()函数：清空所有项
dict1={"name":"xiaozhang","age":"18"}
dict1.clear() #清空字典中的内容
print(dict1)
# get()函数：在字典中通过key获取键值对 *
dict1={"name":"xiaozhang","age":"18"}
value = dict1.get("name")#把get()函数获取值赋值给到value变量
print(value)
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