py3 基础day3(continue0)

字符串不可以修改！！

字典无序！！字典可以嵌套列表和字典！~！！

4.集合操作

集合去重

list_1 = [1,4,5,7,3,6,7,9]
list_1 = set(list_1)

print(list_1,type(list_1))

交集

list_1 = [1,4,5,7,3,6,7,9]
list_1 = set(list_1)
list_2 = set([2,6,0,66,22,8,4])
print(list_1,list_2)
#交集
print(list_1.intersection(list_2))

并集

print(list_1.union(list_2))

#差集

#差集
print(list_1.difference(list_2))
print(list_2.difference(list_1))

#子集

list_3 = set([1,3,7])
print(list_3.issubset(list_2))
print(list_1.issuperset(list_3))

#对称差集
print(list_1.symmetric_difference(list_2))

几何关系

list_1 = [1,4,5,7,3,6,7,9]
list_1 = set(list_1)
list_2 = set([2,6,0,66,22,8,4])
print(list_1,list_2)
#交集
print(list_1.intersection(list_2))
#并集
print(list_1.union(list_2))
#差集
print(list_1.difference(list_2))
print(list_2.difference(list_1))
#子集
list_3 = set([1,3,7])
print(list_3.issubset(list_1))
print(list_1.issuperset(list_3))
#反向差集
print(list_1.symmetric_difference(list_2))

关系运算符

#交集
print(list_1 & list_2)
#union
print(list_1 | list_2)
#diffgerence
print(list_1 - list_2)
#对称差集
print(list_1 ^ list_2)

#添加
list_1.add(888)
list_1.update([66,6666,666])
print(list_1)

5.文件操作

5.文件操作

打开文件

data = open("yesterday",encoding="utf-8").read()
print(data)

f = open("yesterday",encoding="utf-8") #文件句柄
data = f.read()

f = open("yesterday",'r',encoding="utf-8") #文件句柄
data = f.read()

写文件

f = open("yesterday2",'w',encoding="utf-8")
f.write("我爱北京天安门,\n")
f.write("天安门上太阳升")

添加

f = open("yesterday2",'a',encoding="utf-8")
f.write("\n我爱北京天安门,。。。。。\n")
f.write("天安门上太阳升。。。。。")

读文件

f = open("yesterday",'r',encoding="utf-8")
print(f.readline())

读取5行

f = open("yesterday",'r',encoding="utf-8")
for i in range (5):
    print(f.readline())

第九行被取代

f = open("yesterday",'r',encoding="utf-8")
#for line in f.readlines():
    #print(line.strip())
for index,line in enumerate(f.readlines()):
    if index == 9:
        print('---------------')
        continue

运行

D:\Python\python36\python.exe D:/Python/work/day2/file_op.py
Yesterday, all my troubles seemed so far away.
昨日，烦恼离我远去
Now it looks as though they're here to stay.
现在却重回故地
Oh, I believe in yesterday.
哦，我怀念昨日
Suddenly, i not half the man i used to be
突然，我迷失了我自己
There's a shadow hanging over me.
---------------
Oh, yesterday came suddenly.
哦，突然间来到昨日
Why she had to go
为何她远去
I don't know she wouldn't say.
没留下一句话语
I said something wrong,
这都是我的错
Now I long for yesterday.
现在我只渴望昨日
Yesterday, love was such an easy game to play.
昨日，爱情像一种简单的游戏
Now I need a place to hide away.
现在我只有选择逃避
Oh, I believe in yesterday.
哦，我怀念昨日

Process finished with exit code 0

循环（high loop）

f = open("yesterday",'r',encoding="utf-8")
#high loop
count = 0
for line in f:
    if count == 9:
        count += 1
        print('-----删除线-----')
        continue
    print(line)
    count +=1

tell（打印当前位置） 和 seek（光标回到位置）

f = open("yesterday",'r',encoding="utf-8")
print(f.tell())
print(f.readline())
print(f.readline())
print(f.readline())
print(f.tell())
f.seek(0)
print(f.readline())

print(f.encoding)#打印字符

import sys,time
for i in range(30):
    sys.stdout.write("#")
    sys.stdout.flush()
    time.sleep(0.1)

写读

f = open("yesterday",'w+',encoding="utf-8")#写读
print(f.readline())
print(f.readline())
print(f.readline())
f.write("------------")
print(f.readline())

读写

f = open("yesterday",'r+',encoding="utf-8")#r+既可以读，又可以写
#f = open("yesterday",'w+',encoding="utf-8")#写读
print(f.readline())
print(f.readline())
print(f.readline())
f.write("------------")
print(f.readline())

f = open("yesterday",'r+',encoding="utf-8")#r+既可以读，又可以写
f = open("yesterday",'w+',encoding="utf-8")#写读
f = open("yesterday",'a+',encoding="utf-8")#文件句柄，追加读写

f = open("yesterday",'rb')#二进制文件

f = open("yesterday2",'wb')#写二进制文件
f.write("Hello word \n".encode())

py3 基础day3(continue0)

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