python基本操作3（速通版）（上）

#定义字典
d = {}
print(d)
print(type(d))
#key一般情况下使用字符串类型的数据充当，理论上不可变的类型都可以作为key
#只要是可hash的对象都可以作为key
d = {1:"one",2:"two"}
print(d)
d = {"one":"星期一","tow":"星期二"}
print(d)

d = {"one":"星期一","two":"星期二","three":"星期三","four":"星期4"}
print(d)
print(d['one'])
print(d['two'])
print(d['three'])
#赋值
d['four'] = '星期四'
print(d)
print("___________________________________________________________________________")
print(d['one'])
print(d.get('one'))
#下标方式在访问数据时，如果key不存在，就会报错
#get方法方式 访问数据时，如果key不存在，返回none
print(d['two'])
print(d.get('two'))
print(d.get("asd"))

d = {"one":"星期一","two":"星期二","three":"星期三","four":"星期4"}
for k in d:
    print(k)
print("____________________________________________________________________")
#方法1
for k in d:
    print(f'for in :  {k} ---> {d[k]}')
print("____________________________________________________________________")
#方法2
print(d.keys())
for k in d.keys():
    print(f'keys :  {k} ---> {d[k]}')
#方法三
print("____________________________________________________________________")
print(d.values())
for v in d.values():
    print(f'values: {v} ')
#方法四  item里面每一个元素都是一个元组
print("____________________________________________________________________")
print(d.items())
for i in d.items():
    print(f' items :  {i[0]} ---> {i[1]}')
print("____________________________________________________________________")
#解包
for k,v in d.items():
    print(f' items :  {k} ---> {v}')
a,b,c,d,e = 1,2,3,4,5
print(a)
print(e)
#解包编写赋值方式
item = (1,2,3,4,5)
a,b,c,d,e = item
print(a)
print(e)

d = {"one":"星期一","two":"星期二","three":"星期三","four":"星期4"}
#出栈
d.popitem()
print(d)
d.popitem()
print(d)
#pop后面接key可以指定删除的键值对
print("_______________________________________________________________")
d = {"one":"星期一","two":"星期二","three":"星期三","four":"星期4"}
d.pop('one')
print(d)

def creat_card():
    card = {}
    card['name'] = input("请输入姓名: ")
    card['age'] = input("请输入年龄: ")
    card['address'] = input("请输入地址: ")
    return card
def show_card(card):
    for k in card:
        print(f'{k} : {card.get(k)}')
c = creat_card()
show_card(c)

from collections import OrderedDict
my_dict = OrderedDict()
my_dict['one'] = 1
my_dict['two'] = 2
my_dict['three'] = 3
my_dict['four'] = 4
my_dict['five'] = 5
print(my_dict)

#集合定义
s = {}
print(type(s))
s = {1,2,2,3,234,4,5,6666,5,5,5}
print(s)

#集合定义
s = {}
print(type(s))
s = {1,2,2,3,234,4,5,6666,5,5,5}
print(s)
for i in s:
    print(i)

s = "hello"
#字符串转化成列表
l = list(s)
print(l)
print(type(l))
print("_______________________________________________________________")
#集合是无序的
l = set(l)
print(l)
print(type(l))
#列表转化集合
print("_______________________________________________________________")
l = list(s)
l1 = set(l)
print(type(l1))
print(l1)
#列表和集合转化成字符串
print("_______________________________________________________________")
l = list(s)
s1 = str(l)
print(type(s1))
print(s1)
l = set(s)
s1 = str(l)
print(type(s1))
print(s1)

s = "hello" + "itcast"
print(s)
s = [1,2,3,4] + [1,23,4,5]
print(s)
s = ('a','b') + ('c','b')
print(s)
s = "h1" * 4
print(s)

list1 = [1,23,23,4,111,23,111,4,5]
print(max(list1))
print(min(list1))

#for in
c_1 = []
for i in range(100):
    c_1.append(i)
print(len(c_1))
print(c_1)
print("_________________________________________________________________________")
#推导式
c_1 = [i for i in range(100)]  #注意，表达的变量使用要和循环中的变量一致
print(len(c_1))
print(c_1)

a = [x for x in range(3,10) if x%2==0]
print(a)
print("______________________________________________________________")
a = [x for x in range(3,10) if x%2!=0]
print(a)
print("______________________________________________________________")
a = [x for x in range(3,10)]
print(a)

#两个for
a = [(x,y) for x in range(1,3) for y in range(3)]
print(a)
print("_____________________________________________________________________________")
#多个for
a = [(x,y,z) for x in range(1,3) for y in range(3) for z in range(5,10) if z%2!=0]
print(a)