What's the difference between:
isinstance(foo, types.StringType)
and
i开发者_如何学JAVAsinstance(foo, basestring)
?
For Python2: basestring
is the base class for both str
and unicode
, while types.StringType
is str
. If you want to check if something is a string, use basestring
. If you want to check if something is a bytestring, use str
and forget about types
.
This stuff is completely different in Python3
types
not longer has StringType
str
is always unicode
basestring
no longer exists
So try not to sprinkle that stuff through your code too much if you might ever need to port it
>>> import types
>>> isinstance(u'ciao', types.StringType)
False
>>> isinstance(u'ciao', basestring)
True
>>>
Pretty important difference, it seems to me;-).
For Python 2.x:
try:
basestring # added in Python 2.3
except NameError:
basestring = (str, unicode)
...
if isinstance(foo, basestring):
...
Of course this might not work for Python 3, but I'm quite sure the 2to3 converter will take care of the topic.
If you need to write code that works in both Python 2 and Python 3 you can use install future
via pip install future
and import from past.builtins import basestring
.
from past.builtins import basestring
See https://python-future.org/compatible_idioms.html#strings-and-bytes
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