Python，如何从文件读取字节并将其保存？

Question

我想从文件读取字节，然后将那些字节写入另一个文件，然后保存该文件。

我该怎么做呢？

Answer 1

这是使用Python中的基本文件操作的方法。这将打开一个文件，将数据读入内存，然后打开第二个文件并将其写出。

in_file = open("in-file", "rb") # opening for [r]eading as [b]inary
data = in_file.read() # if you only wanted to read 512 bytes, do .read(512)
in_file.close()

out_file = open("out-file", "wb") # open for [w]riting as [b]inary
out_file.write(data)
out_file.close()

通过使用with键盘处理关闭文件，我们可以更简洁地执行此操作。

with open("in-file", "rb") as in_file, open("out-file", "wb") as out_file:
    out_file.write(in_file.read())

如果您不想将整个文件存储在内存中，则可以分段传输。

piece_size = 4096 # 4 KiB

with open("in-file", "rb") as in_file, open("out-file", "wb") as out_file:
    while True:
        piece = in_file.read(piece_size)

        if piece == "":
            break # end of file

        out_file.write(piece)