写入然后读取内存字节(BytesIO)会得到空白结果 [英] Writing then reading in-memory bytes (BytesIO) gives a blank result
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问题描述
我想尝试python BytesIO类。
I wanted to try out the python BytesIO class.
作为一个实验,我尝试写入内存中的zip文件,然后从中读取字节压缩文件。因此,我没有传递文件对象到 gzip
,而是传递了 BytesIO
对象。这是整个脚本:
As an experiment I tried writing to a zip file in memory, and then reading the bytes back out of that zip file. So instead of passing in a file-object to gzip
, I pass in a BytesIO
object. Here is the entire script:
from io import BytesIO
import gzip
# write bytes to zip file in memory
myio = BytesIO()
g = gzip.GzipFile(fileobj=myio, mode='wb')
g.write(b"does it work")
g.close()
# read bytes from zip file in memory
g = gzip.GzipFile(fileobj=myio, mode='rb')
result = g.read()
g.close()
print(result)
但是它返回一个空的 bytes
对象,以获取结果
。在Python 2.7和3.4中都会发生这种情况。我缺少什么?
But it is returning an empty bytes
object for result
. This happens in both Python 2.7 and 3.4. What am I missing?
推荐答案
您需要 seek
回到文件的开头...
You need to seek
back to the beginning of the file after writing the initial in memory file...
myio.seek(0)
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