IO流文件读写

#P1 打开文件、读文件、关闭文件的典型方法try:    f=open('D:/test.txt','r')    print(f.read())finally:    if f:        f.close()#P2 推荐的简洁写法，不必显示的关闭文件描述符#open返回的对象在python中称作file-like 对象，可以是字节流、网络流、自定义流等with open('D:/test.txt','r') as f:    #按行读取    for line in f.readlines():        print(line.strip())#P3 直接读取二级制的图片、视频文件# with open('D:/banner.jpg','rb') as f2:#     for line in f2.readlines():#         print(line.strip())#P4 可以指定编码读取相应的数据,还可以忽略非法编码with open('D:/test.txt','r',encoding='gbk',errors='ignore') as f3:    for line in f3.readlines():        print(line.strip())#P5 写文件的流程和读文件是一样的 代开文件、写入内容、关闭文件# 'r'    open for reading (default)# 'w'    open for writing, truncating the file first# 'x'    open for exclusive creation, failing if the file already exists# 'a'    open for writing, appending to the end of the file if it exists# 'b'    binary mode# 't'    text mode (default)# '+'    open a disk file for updating (reading and writing)# 'U'    universal newlines mode (deprecated)with open('D:/test12.txt','a+') as f4:    for line in f4.readlines():        print(line.strip())    f4.write('a new line2!')