Python学习-0611

一、with上下文管理
with open('今日内容.txt',mode='rt',encoding='utf-8') as f1:
    data = f1.read()
    print(data)
    自动调用f1.close()回收操作系统

with open('a.py', mode='rt', encoding='utf-8') as f1, \
        open('a.py', mode='rt', encoding='utf-8') as f2:
    print('文件1的内容'.center(50, '#'))
    data = f1.read()
    print(data)

    print('文件2的内容'.center(50, '#'))
    data = f2.read()
    print(data)
    # 自动调用f1.close()、f2.close()回收操作系统

二、bytes

with open('a.txt',mode='rt') as f:
     data=f.read()
     print(data)
     print(type(data))
t模式只能用于读文本文件
with open('a.jpg',mode='rt',encoding='utf-8') as f:
    data=f.read()
    print(data)
    print(type(data))
 图片<---------jpg-------二进制数
 字符<---------utf-8-------二进制数
b模式可能用于读所有的文件
with open('a.jpg',mode='rb') as f:
    data=f.read()
    print(data)
    print(type(data))
with open('a.jpg', mode='rb') as f:
     data = f.read()
     print(data.decode("utf-8"))
print(type(data))

b模式
二进制数
t模式是帮我们解码了
字符<---------utf-8-------二进制数
编码操作：
字符串===utf-8===》bytes
res=user.encode("utf-8")
print(res)
print(type(res))
基于网络发送数据(res)
解码操作：
bytes====》utf-8=====》字符串
print(res.decode("utf-8"))
with open('a.jpg', mode='rb') as src_f, \
        open('b.jpg', mode='wb') as dst_f:
    data = src_f.read()
    dst_f.write(data)
for line in src_f:
    dst_f.write(line)

with open('b.txt', mode='wb') as f:
    user = "林海峰"
    res=user.encode('utf-8')
    f.write(res)
with open('b.txt', mode='wt', encoding="utf-8") as f:
    user = "林海峰"
    f.write(user)

三、+模式

可读可写模式,可以省略t，默认就是t模式，读写都是以字符串为单位
r+t
w+t
a+t

可读可写模式，b模式下读写都是以bytes二进制为单位
r+b
w+b
a+b
with open('b.txt',mode='r+t',encoding='utf-8') as f:
    print(f.read())
    f.write("abcdefg")
with open('b.txt',mode='w+t',encoding='utf-8') as f:
    f.write("我爱你中国")
    print(f.read())
with open('b.txt',mode='a+t',encoding='utf-8') as f:
    f.write("我爱你中国")
    print(f.read())

四、文件操作的其他内容

with open('b.txt', mode='rt', encoding='utf-8') as f:

    line1=f.readline()
    line2=f.readline()
    line3=f.readline()
    line4=f.readline()
    print(line1,end="")
    print(line2,end="")
    print(line3,end="")
    print(line4,end="")

for line in f:
    print(line)
l = []
for line in f:
     l.append(line)
     l = f.readlines()
     print(l)

with open('b.txt', mode='wt', encoding='utf-8') as f:
    f.write("1111\n2222\n333\n")
    lines=["1111\n","222\n","333\n"]
    for line in lines:
        f.write(line)

with open('b.txt', mode='wt', encoding='utf-8') as f:
    f.write("1111\n2222\n333\n")
    lines=["1111","222","333"]
    for line in lines:
        f.write(line)

f.writelines(lines)
f.writelines({'k1':111,'k2':222,"k3":3333})
f.writelines("hello")
f.write("hello")
with open(r'b.txt', mode='wt', encoding='utf-8') as f:
    f.write('哈哈哈\n')
    f.flush()