![]() ![]() These have to provide the interface defined by the base classes Incremental encoder and decoder classes or factory functions. ![]() incrementalencoder ¶ incrementaldecoder ¶ The functions or methods are expected to work in a stateless mode. The encode() and decode() methods of Codec These must beįunctions or methods which have the same interface as The stateless encoding and decoding functions. The constructorĪrguments are stored in attributes of the same name: name ¶ CodecInfo ( encode, decode, streamreader = None, streamwriter = None, incrementalencoder = None, incrementaldecoder = None, name = None ) ¶Ĭodec details when looking up the codec registry. Is stored in the cache and returned to the caller. If no CodecInfo object isįound, a LookupError is raised. Looks up the codec info in the Python codec registry and returns aĮncodings are first looked up in the registry’s cache. The full details for each codec can also be looked up directly: codecs. decode ( obj, encoding = 'utf-8', errors = 'strict' ) ¶ĭecodes obj using the codec registered for encoding.ĭefault error handler is 'strict' meaning that decoding errors raise ValueError (or a more codec specific subclass, such as Theĭefault error handler is 'strict' meaning that encoding errors raise encode ( obj, encoding = 'utf-8', errors = 'strict' ) ¶Įncodes obj using the codec registered for encoding.Įrrors may be given to set the desired error handling scheme. The module defines the following functions for encoding and decoding withĪny codec: codecs. Text encodings or with codecs that encode to Types, but some module features are restricted to be used specifically with Custom codecs may encode and decode between arbitrary Most standard codecsĪre text encodings, which encode text to bytes (andĭecode bytes to text), but there are also codecs provided that encode text to Manages the codec and error handling lookup process. This module defines base classes for standard Python codecs (encoders andĭecoders) and provides access to the internal Python codec registry, which Python 3000 will prohibit encoding of bytes, according to PEP 3137: "encoding always takes a Unicode string and returns a bytes sequence, and decoding always takes a bytes sequence and returns a Unicode string".Codecs - Codec registry and base classes ¶ UnicodeDecodeError: 'ascii' codec can't decode byte 0xd0 in position 0: ordinal not in range(128) > "\xd0\x91".encode("utf-8") # Unexpected argument type. > "a".encode("utf-8") # Unexpected argument type. As of Python2.5, this is not implemented.Īlternatively, a TypeError exception could always be thrown on receiving an str argument in encode() functions. However, a more flexible treatment of the unexpected str argument type might first validate the str argument by decoding it, then return it unmodified if the validation was successful. This is because the str result of encode() must be a legal coding-specific sequence. Unlike a similar case with UnicodeEncodeError, such a failure cannot be always avoided. Hence a decoding failure inside an encoder. It also appears that such "up-conversion" makes no assumption of str parameter's coding, choosing a default ascii decoder. It appears that on seeing an str parameter, the encode() functions "up-convert" it into unicode before converting to their own coding. The cause of it seems to be the coding-specific encode() functions that normally expect a parameter of type unicode. Paradoxically, a UnicodeDecodeError may happen when _encoding_. UnicodeDecodeError: 'utf8' codec can't decode byte 0x81 in position 0: unexpected code byte Since codings map only a limited number of str strings to unicode characters, an illegal sequence of str characters will cause the coding-specific decode() to fail.įile "encodings/utf_8.py", line 16, in decode The UnicodeDecodeError normally happens when decoding an str string from a certain coding. ![]()
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