什么是元组:
Python的元组与列表类似,不同之处在于元组的元素不能修改。
元组使用小括号,列表使用方括号。
格式:
变量名=(,,,,)
aTuple=(23,35,56,34,11,21)
通过索引取数据
aTuple=(23,35,56,34,11,21) print(aTuple[2]) #56
索引值不存在时,会报错
count查询出现的个数
index:查询元素的索引,有对应的元素返回对应的索引,否则报错
元组时不可以修改数据的
列表转换元组
aa = [23,34,45,56,67]
tuple(aa)
print(aa)
#[23, 34, 45, 56, 67]
元组转换列表
aTuple=('b','c','d','e','f','g')
a = list(aTuple)
print(a)
#['b', 'c', 'd', 'e', 'f', 'g']
元组循环取值
for循环
aTuple=('b','c','d','e','f','g')
for i in aTuple:
print(i)
while循环
aTuple=('b','c','d','e','f','g')
i=0
while i < len(aTuple):
print(aTuple[i])
i=i+1
字典的格式
变量名={key1:value,key2:value,,,}
info = {"name":"jack","age":12,"sex":"男"}
有对应的key
info = {"name":"jack","age":12,"sex":"男"}
print(info["name"])
#jack
无对应的key
info = {"name":"jack","age":12,"sex":"男"}
print(info["name12"])
#KeyError: 'name12'
我们不确定字典中是否存在某个键而又想获取其值时,如何 *** 作?
案例:有对应key的
info = {"name":"jack","age":12,"sex":"男"}
print(info.get("name"))
#jack
没有对应的key
info = {"name":"jack","age":12,"sex":"男"}
print(info.get("name"))
#None
字典的每个元素中的数据是可以修改的,只要通过key找到,即可修改,否则是新增
info = {"name":"jack","age":12,"sex":"男"}
info["age"] =14
print(info)
#{'name': 'jack', 'age': 14, 'sex': '男'}
没有对应的key时,默认为新增
info = {"name":"jack","age":12,"sex":"男"}
info["gender"] ="属鸡"
print(info)
#{'name': 'jack', 'age': 12, 'sex': '男', 'gender': '属鸡'}
删除整个字典
info = {"name":"jack","age":12,"sex":"男"}
del info
print(info)
#NameError: name 'info' is not defined
删除一条元素
info = {"name":"jack","age":12,"sex":"男"}
del info["name"]
print(info)
#{'age': 12, 'sex': '男'}
clear:清空数据
info = {"name":"jack","age":12,"sex":"男"}
info.clear()
print(info)
#{}
len():查询键值对的个数
info = {"name":"jack","age":12,"sex":"男"}
print(len(info))
#3
取出字典中的key
info = {"name":"jack","age":12,"sex":"男"}
for i in info.keys():
print(i)
结果:name age sex
取出字典中的value
info = {"name":"jack","age":12,"sex":"男"}
for i in info.values():
print(i)
结果:jack 12 男
取出字典中的key和value
info = {"name":"jack","age":12,"sex":"男"}
for i in info.keys():
print(i,info[i])
info = {"name":"jack","age":12,"sex":"男"}
for k,v in info.items():
print(k,v)
names=["jack","tom","Meachal"]
for i,chr in enumerate(names):
print(i,chr)
返回值 0 jack 1 tom 2 Meachal
欢迎分享,转载请注明来源:内存溢出
评论列表(0条)