Python3 错误：initial_value 必须是 str 或 None，带有 StringIO
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Python3 error: initial_value must be str or None, with StringIO
提问by AMisra
While porting code from python2to 3, I get this error when reading from a URL
从python2to移植代码3时，从 URL 读取时出现此错误
TypeError: initial_value must be str or None, not bytes.
类型错误：initial_value 必须是 str 或 None，而不是字节。
import urllib
import json
import gzip
from urllib.parse import urlencode
from urllib.request import Request
service_url = 'https://babelfy.io/v1/disambiguate'
text = 'BabelNet is both a multilingual encyclopedic dictionary and a semantic network'
lang = 'EN'
Key = 'KEY'
params = {
'text' : text,
'key' : Key,
'lang' :'EN'
}
url = service_url + '?' + urllib.urlencode(params)
request = Request(url)
request.add_header('Accept-encoding', 'gzip')
response = urllib.request.urlopen(request)
if response.info().get('Content-Encoding') == 'gzip':
buf = StringIO(response.read())
f = gzip.GzipFile(fileobj=buf)
data = json.loads(f.read())
The exception is thrown at this line
在这一行抛出异常
buf = StringIO(response.read())
If I use python2, it works fine.
如果我使用 python2，它工作正常。
采纳答案by tynn
response.read()returns an instance of byteswhile StringIOis an in-memory stream for text only. Use BytesIOinstead.
response.read()返回byteswhile的实例StringIO是仅用于文本的内存中流。使用BytesIO来代替。
From What's new in Python 3.0 - Text Vs. Data Instead Of Unicode Vs. 8-bit
来自Python 3.0 的新增功能 - 文本 Vs。数据而不是 Unicode Vs。8 位
The
StringIOandcStringIOmodules are gone. Instead, import theiomodule and useio.StringIOorio.BytesIOfor text and data respectively.
在
StringIO和cStringIO模块都没有了。相反，导入io模块并分别使用io.StringIO或io.BytesIO用于文本和数据。
回答by gabhijit
This looks like another python3 bytesvs. strproblem. Your response is of type bytes(which is different in python 3 from str). You need to get it into a string first using response.read().decode('utf-8')say and then use StringIOon it. Or you may want to use BytesIOas someone said - but if you expect it to be str, preferred way is to decodeinto an strfirst.
这看起来像是另一个 python3 bytesvs.str问题。您的回复属于类型bytes（在 python 3 中与 不同str）。您需要先使用response.read().decode('utf-8')say将其放入一个字符串中，然后再使用StringIO它。或者你可能想像BytesIO某人说的那样使用- 但如果你期望它是str，首选的方法是decode进入str第一个。
回答by Max Bileschi
Consider using six.StringIO instead of io.StringIO.
考虑使用 Six.StringIO 而不是 io.StringIO。
