Get Spectral Python Official Version For Mac

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The get-pip.py script is supported on the same python version as pip. For the now unsupported Python 2.6, alternate script is available here. Join the official Python Developers Survey 2018 and win valuable prizes. Object-oriented Python package for processing spectral data – or in general, n-dimensional data with labeled axes. First version distributed on pypi.python.org.

When you are planning to start working on the Macbook for your Machine Learning or Deep Learning Related Tasks, it will not have all the tools and libraries. Below are various steps to setup each of these for you to be able to do Machine Learning or Deep Learning using Python. First step on MacBook when you get it new is to install Homebrew. First you need to open the Terminal on Mac. It is just like Command Line in Windows, in case you are new to MacOS.

Use iTerm 2, instead of default terminal, it is great. You can instal iTerm 2 by downloading it from, you just need to download and move that file to Applications, so that becomes a standard app. How to Install Homebrew? Homebrew is a package manager for MacOS and lets you install any missing packages easily. You install Homebrew by below command by pasting in Terminal. If you get any prompts, just say yes, it will install respective packages and CLI tools.

/usr/bin/ruby -e '$(curl -fsSL You can go to website to get the latest info How to install wget? Wget is a very commonly used command and it is not available by default on Mac. You can install wget using HomeBrew by using below command in Terminal.

Brew install wget -with-libressl How to install Anaconda – Python Distribution on Mac using Terminal? Anaconda is a famous python distribution for Machine Learning or Deep learning. You can setup using terminal as below. We are installing 3.6 version directly using CLI. Anaconda Distributions are at. Go to terminal and type wget it is about 500 MB and can take a minute or two. Next you type the below command to install.

Bash Anaconda3-5.0.1-MacOSX-x8664.sh It will take 5 to 7 min to install this. It will ask for few prompts, just say Yes or hit enter for everything, so that it takes default settings. To make sure the installation is applied to your terminal, I suggest you quit the terminal and then re-lauch the terminal. You can verify if it is the right version installed by using the below command python -version or you can also type command conda to see if Anaconda is installed Setting up tmux for better management of terminals tmux is a terminal multiplexer. It is great, when you are working with remote terminals, especially in Machine Learning world you will have AWS GPUs or Google’s etc. This will help you mange the sessions well and have it running in background.

More details at. You can use the below command to install tmux brew install tmux Now, you can type tmux command on terminal, you should see a normal window.

You can see TMUX Info here: http://www.hamvocke.com/blog/a-quick-and-easy-guide-to-tmux/. Leave a Comment Comments Policy:. Comments are to drive conversation, add your thoughts, experiences, ask questions!.

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— Codec registry and base classes This module defines base classes for standard Python codecs (encoders and decoders) and provides access to the internal Python codec registry, which manages the codec and error handling lookup process. Most standard codecs are, which encode text to bytes, but there are also codecs provided that encode text to text, and bytes to bytes. Custom codecs may encode and decode between arbitrary types, but some module features are restricted to use specifically with, or with codecs that encode to. The module defines the following functions for encoding and decoding with any codec: codecs.

Encode ( obj , encoding , errors ) Encodes obj using the codec registered for encoding. The default encoding is utf-8. Errors may be given to set the desired error handling scheme.

The default error handler is 'strict' meaning that encoding errors raise (or a more codec specific subclass, such as ). Refer to for more information on codec error handling.

Decode ( obj , encoding , errors ) Decodes obj using the codec registered for encoding. The default encoding is utf-8. Errors may be given to set the desired error handling scheme. The default error handler is 'strict' meaning that decoding errors raise (or a more codec specific subclass, such as ). Refer to for more information on codec error handling.

The full details for each codec can also be looked up directly: codecs. Lookup ( encoding ) Looks up the codec info in the Python codec registry and returns a object as defined below. Encodings are first looked up in the registry’s cache. If not found, the list of registered search functions is scanned. If no object is found, a is raised.

Otherwise, the object is stored in the cache and returned to the caller. Class codecs. CodecInfo ( encode, decode, streamreader=None, streamwriter=None, incrementalencoder=None, incrementaldecoder=None, name=None ) Codec details when looking up the codec registry.

The constructor arguments are stored in attributes of the same name: name The name of the encoding. Encode decode The stateless encoding and decoding functions. These must be functions or methods which have the same interface as the and methods of Codec instances (see ).

The functions or methods are expected to work in a stateless mode. Incrementalencoder incrementaldecoder Incremental encoder and decoder classes or factory functions. These have to provide the interface defined by the base classes and, respectively. Incremental codecs can maintain state. Streamwriter streamreader Stream writer and reader classes or factory functions. These have to provide the interface defined by the base classes and, respectively. Stream codecs can maintain state.

To simplify access to the various codec components, the module provides these additional functions which use for the codec lookup: codecs. Getencoder ( encoding ) Look up the codec for the given encoding and return its encoder function. Raises a in case the encoding cannot be found. Getdecoder ( encoding ) Look up the codec for the given encoding and return its decoder function. Raises a in case the encoding cannot be found.

Getincrementalencoder ( encoding ) Look up the codec for the given encoding and return its incremental encoder class or factory function. Raises a in case the encoding cannot be found or the codec doesn’t support an incremental encoder. Getincrementaldecoder ( encoding ) Look up the codec for the given encoding and return its incremental decoder class or factory function. Raises a in case the encoding cannot be found or the codec doesn’t support an incremental decoder. Getreader ( encoding ) Look up the codec for the given encoding and return its StreamReader class or factory function. Raises a in case the encoding cannot be found.

Getwriter ( encoding ) Look up the codec for the given encoding and return its StreamWriter class or factory function. Raises a in case the encoding cannot be found. Custom codecs are made available by registering a suitable codec search function: codecs. Register ( searchfunction ) Register a codec search function. Search functions are expected to take one argument, being the encoding name in all lower case letters, and return a object. In case a search function cannot find a given encoding, it should return None. Note Search function registration is not currently reversible, which may cause problems in some cases, such as unit testing or module reloading.

While the builtin and the associated module are the recommended approach for working with encoded text files, this module provides additional utility functions and classes that allow the use of a wider range of codecs when working with binary files: codecs. Open ( filename, mode='r', encoding=None, errors='strict', buffering=1 ) Open an encoded file using the given mode and return an instance of, providing transparent encoding/decoding. The default file mode is 'r', meaning to open the file in read mode.

Note Underlying encoded files are always opened in binary mode. No automatic conversion of ' n' is done on reading and writing.

The mode argument may be any binary mode acceptable to the built-in function; the 'b' is automatically added. Encoding specifies the encoding which is to be used for the file. Any encoding that encodes to and decodes from bytes is allowed, and the data types supported by the file methods depend on the codec used. Errors may be given to define the error handling. It defaults to 'strict' which causes a to be raised in case an encoding error occurs.

Buffering has the same meaning as for the built-in function. It defaults to line buffered. EncodedFile ( file, dataencoding, fileencoding=None, errors='strict' ) Return a instance, a wrapped version of file which provides transparent transcoding. The original file is closed when the wrapped version is closed. Data written to the wrapped file is decoded according to the given dataencoding and then written to the original file as bytes using fileencoding.

Bytes read from the original file are decoded according to fileencoding, and the result is encoded using dataencoding. If fileencoding is not given, it defaults to dataencoding. Errors may be given to define the error handling. It defaults to 'strict', which causes to be raised in case an encoding error occurs. Iterencode ( iterator, encoding, errors='strict',.kwargs ) Uses an incremental encoder to iteratively encode the input provided by iterator. This function is a. The errors argument (as well as any other keyword argument) is passed through to the incremental encoder.

Iterdecode ( iterator, encoding, errors='strict',.kwargs ) Uses an incremental decoder to iteratively decode the input provided by iterator. This function is a. The errors argument (as well as any other keyword argument) is passed through to the incremental decoder. The module also provides the following constants which are useful for reading and writing to platform dependent files: codecs. BOMBE codecs. BOMLE codecs.

BOMUTF8 codecs. BOMUTF16 codecs. BOMUTF16BE codecs. BOMUTF16LE codecs. BOMUTF32 codecs. BOMUTF32BE codecs.

BOMUTF32LE These constants define various byte sequences, being Unicode byte order marks (BOMs) for several encodings. They are used in UTF-16 and UTF-32 data streams to indicate the byte order used, and in UTF-8 as a Unicode signature. Is either or depending on the platform’s native byte order, is an alias for, for and for. The others represent the BOM in UTF-8 and UTF-32 encodings. Codec Base Classes The module defines a set of base classes which define the interfaces for working with codec objects, and can also be used as the basis for custom codec implementations. Each codec has to define four interfaces to make it usable as codec in Python: stateless encoder, stateless decoder, stream reader and stream writer. The stream reader and writers typically reuse the stateless encoder/decoder to implement the file protocols.

Codec authors also need to define how the codec will handle encoding and decoding errors. Error Handlers To simplify and standardize error handling, codecs may implement different error handling schemes by accepting the errors string argument. The following string values are defined and implemented by all standard Python codecs: Value Meaning 'strict' Raise (or a subclass); this is the default. Implemented in.

'ignore' Ignore the malformed data and continue without further notice. Implemented in. The following error handlers are only applicable to: Value Meaning 'replace' Replace with a suitable replacement marker; Python will use the official U+FFFD REPLACEMENT CHARACTER for the built-in codecs on decoding, and ‘?’ on encoding. Implemented in.

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'xmlcharrefreplace' Replace with the appropriate XML character reference (only for encoding). Implemented in. 'backslashreplace' Replace with backslashed escape sequences (only for encoding).

Implemented in. 'surrogateescape' On decoding, replace byte with individual surrogate code ranging from U+DC80 to U+DCFF. This code will then be turned back into the same byte when the 'surrogateescape' error handler is used when encoding the data. (See for more.) In addition, the following error handler is specific to the given codecs: Value Codecs Meaning 'surrogatepass' utf-8, utf-16, utf-32, utf-16-be, utf-16-le, utf-32-be, utf-32-le Allow encoding and decoding of surrogate codes. These codecs normally treat the presence of surrogates as an error.

Changed in version 3.4: The 'surrogatepass' error handlers now works with utf-16. and utf-32. codecs.

The set of allowed values can be extended by registering a new named error handler: codecs. Registererror ( name, errorhandler ) Register the error handling function errorhandler under the name name. The errorhandler argument will be called during encoding and decoding in case of an error, when name is specified as the errors parameter. For encoding, errorhandler will be called with a instance, which contains information about the location of the error. The error handler must either raise this or a different exception, or return a tuple with a replacement for the unencodable part of the input and a position where encoding should continue.

The replacement may be either. If the replacement is bytes, the encoder will simply copy them into the output buffer. If the replacement is a string, the encoder will encode the replacement.

Encoding continues on original input at the specified position. Negative position values will be treated as being relative to the end of the input string. If the resulting position is out of bound an will be raised. Decoding and translating works similarly, except or will be passed to the handler and that the replacement from the error handler will be put into the output directly. Previously registered error handlers (including the standard error handlers) can be looked up by name: codecs. Lookuperror ( name ) Return the error handler previously registered under the name name. Raises a in case the handler cannot be found.

The following standard error handlers are also made available as module level functions: codecs. Stricterrors ( exception ) Implements the 'strict' error handling: each encoding or decoding error raises a. Replaceerrors ( exception ) Implements the 'replace' error handling (for only): substitutes '?'

For encoding errors (to be encoded by the codec), and ' ufffd' (the Unicode replacement character) for decoding errors. Ignoreerrors ( exception ) Implements the 'ignore' error handling: malformed data is ignored and encoding or decoding is continued without further notice.

Xmlcharrefreplaceerrors ( exception ) Implements the 'xmlcharrefreplace' error handling (for encoding with only): the unencodable character is replaced by an appropriate XML character reference. Backslashreplaceerrors ( exception ) Implements the 'backslashreplace' error handling (for encoding with only): the unencodable character is replaced by a backslashed escape sequence. Stateless Encoding and Decoding The base Codec class defines these methods which also define the function interfaces of the stateless encoder and decoder: Codec.

Encode ( input , errors ) Encodes the object input and returns a tuple (output object, length consumed). For instance, converts a string object to a bytes object using a particular character set encoding (e.g., cp1252 or iso-8859-1). The errors argument defines the error handling to apply. It defaults to 'strict' handling. The method may not store state in the Codec instance. Use for codecs which have to keep state in order to make encoding efficient. The encoder must be able to handle zero length input and return an empty object of the output object type in this situation.

Decode ( input , errors ) Decodes the object input and returns a tuple (output object, length consumed). For instance, for a, decoding converts a bytes object encoded using a particular character set encoding to a string object. For text encodings and bytes-to-bytes codecs, input must be a bytes object or one which provides the read-only buffer interface – for example, buffer objects and memory mapped files. The errors argument defines the error handling to apply. It defaults to 'strict' handling. The method may not store state in the Codec instance. Use for codecs which have to keep state in order to make decoding efficient.

The decoder must be able to handle zero length input and return an empty object of the output object type in this situation. Incremental Encoding and Decoding The and classes provide the basic interface for incremental encoding and decoding. Encoding/decoding the input isn’t done with one call to the stateless encoder/decoder function, but with multiple calls to the / method of the incremental encoder/decoder. The incremental encoder/decoder keeps track of the encoding/decoding process during method calls.

The joined output of calls to the / method is the same as if all the single inputs were joined into one, and this input was encoded/decoded with the stateless encoder/decoder. IncrementalEncoder Objects The class is used for encoding an input in multiple steps.

It defines the following methods which every incremental encoder must define in order to be compatible with the Python codec registry. Class codecs. IncrementalEncoder ( errors='strict' ) Constructor for an instance. All incremental encoders must provide this constructor interface. They are free to add additional keyword arguments, but only the ones defined here are used by the Python codec registry. The may implement different error handling schemes by providing the errors keyword argument. See for possible values.

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The errors argument will be assigned to an attribute of the same name. Assigning to this attribute makes it possible to switch between different error handling strategies during the lifetime of the object.

Encode ( object , final ) Encodes object (taking the current state of the encoder into account) and returns the resulting encoded object. If this is the last call to final must be true (the default is false). Reset ( ) Reset the encoder to the initial state.

The output is discarded: call.encode(object, final=True), passing an empty byte or text string if necessary, to reset the encoder and to get the output. Getstate ( ) Return the current state of the encoder which must be an integer. The implementation should make sure that 0 is the most common state. (States that are more complicated than integers can be converted into an integer by marshaling/pickling the state and encoding the bytes of the resulting string into an integer).

Setstate ( state ) Set the state of the encoder to state. State must be an encoder state returned. IncrementalDecoder Objects The class is used for decoding an input in multiple steps. It defines the following methods which every incremental decoder must define in order to be compatible with the Python codec registry.

Class codecs. IncrementalDecoder ( errors='strict' ) Constructor for an instance. All incremental decoders must provide this constructor interface. They are free to add additional keyword arguments, but only the ones defined here are used by the Python codec registry. The may implement different error handling schemes by providing the errors keyword argument. See for possible values. The errors argument will be assigned to an attribute of the same name.

Assigning to this attribute makes it possible to switch between different error handling strategies during the lifetime of the object. Decode ( object , final ) Decodes object (taking the current state of the decoder into account) and returns the resulting decoded object. If this is the last call to final must be true (the default is false). If final is true the decoder must decode the input completely and must flush all buffers. If this isn’t possible (e.g. Because of incomplete byte sequences at the end of the input) it must initiate error handling just like in the stateless case (which might raise an exception).

Reset ( ) Reset the decoder to the initial state. Getstate ( ) Return the current state of the decoder. This must be a tuple with two items, the first must be the buffer containing the still undecoded input. The second must be an integer and can be additional state info. (The implementation should make sure that 0 is the most common additional state info.) If this additional state info is 0 it must be possible to set the decoder to the state which has no input buffered and 0 as the additional state info, so that feeding the previously buffered input to the decoder returns it to the previous state without producing any output. (Additional state info that is more complicated than integers can be converted into an integer by marshaling/pickling the info and encoding the bytes of the resulting string into an integer.) setstate ( state ) Set the state of the encoder to state. State must be a decoder state returned.

StreamWriter Objects The class is a subclass of Codec and defines the following methods which every stream writer must define in order to be compatible with the Python codec registry. Class codecs. StreamWriter ( stream, errors='strict' ) Constructor for a instance. All stream writers must provide this constructor interface.

They are free to add additional keyword arguments, but only the ones defined here are used by the Python codec registry. The stream argument must be a file-like object open for writing text or binary data, as appropriate for the specific codec. The may implement different error handling schemes by providing the errors keyword argument. See for the standard error handlers the underlying stream codec may support. The errors argument will be assigned to an attribute of the same name. Assigning to this attribute makes it possible to switch between different error handling strategies during the lifetime of the object.

Write ( object ) Writes the object’s contents encoded to the stream. Writelines ( list ) Writes the concatenated list of strings to the stream (possibly by reusing the method). The standard bytes-to-bytes codecs do not support this method. Reset ( ) Flushes and resets the codec buffers used for keeping state. Calling this method should ensure that the data on the output is put into a clean state that allows appending of new fresh data without having to rescan the whole stream to recover state.

In addition to the above methods, the must also inherit all other methods and attributes from the underlying stream. StreamReader Objects The class is a subclass of Codec and defines the following methods which every stream reader must define in order to be compatible with the Python codec registry. Class codecs. StreamReader ( stream, errors='strict' ) Constructor for a instance.

All stream readers must provide this constructor interface. They are free to add additional keyword arguments, but only the ones defined here are used by the Python codec registry. The stream argument must be a file-like object open for reading text or binary data, as appropriate for the specific codec.

The may implement different error handling schemes by providing the errors keyword argument. See for the standard error handlers the underlying stream codec may support. The errors argument will be assigned to an attribute of the same name. Assigning to this attribute makes it possible to switch between different error handling strategies during the lifetime of the object.

The set of allowed values for the errors argument can be extended with. Read ( size , chars , firstline ) Decodes data from the stream and returns the resulting object.

The chars argument indicates the number of decoded code points or bytes to return. The method will never return more data than requested, but it might return less, if there is not enough available.

The size argument indicates the approximate maximum number of encoded bytes or code points to read for decoding. The decoder can modify this setting as appropriate. The default value -1 indicates to read and decode as much as possible. This parameter is intended to prevent having to decode huge files in one step. The firstline flag indicates that it would be sufficient to only return the first line, if there are decoding errors on later lines.

The method should use a greedy read strategy meaning that it should read as much data as is allowed within the definition of the encoding and the given size, e.g. If optional encoding endings or state markers are available on the stream, these should be read too. Readline ( size , keepends ) Read one line from the input stream and return the decoded data. Size, if given, is passed as size argument to the stream’s method. If keepends is false line-endings will be stripped from the lines returned. Readlines ( sizehint , keepends ) Read all lines available on the input stream and return them as a list of lines. Line-endings are implemented using the codec’s decoder method and are included in the list entries if keepends is true.

Sizehint, if given, is passed as the size argument to the stream’s method. Reset ( ) Resets the codec buffers used for keeping state. Note that no stream repositioning should take place. This method is primarily intended to be able to recover from decoding errors. In addition to the above methods, the must also inherit all other methods and attributes from the underlying stream.

StreamReaderWriter Objects The is a convenience class that allows wrapping streams which work in both read and write modes. The design is such that one can use the factory functions returned by the function to construct the instance.

Class codecs. StreamReaderWriter ( stream, Reader, Writer, errors ) Creates a instance. Stream must be a file-like object.

Reader and Writer must be factory functions or classes providing the and interface resp. Error handling is done in the same way as defined for the stream readers and writers. Instances define the combined interfaces of and classes.

They inherit all other methods and attributes from the underlying stream. StreamRecoder Objects The translates data from one encoding to another, which is sometimes useful when dealing with different encoding environments. The design is such that one can use the factory functions returned by the function to construct the instance. Class codecs. StreamRecoder ( stream, encode, decode, Reader, Writer, errors ) Creates a instance which implements a two-way conversion: encode and decode work on the frontend — the data visible to code calling read and write, while Reader and Writer work on the backend — the data in stream. You can use these objects to do transparent transcodings from e.g.

Latin-1 to UTF-8 and back. The stream argument must be a file-like object. The encode and decode arguments must adhere to the Codec interface. Reader and Writer must be factory functions or classes providing objects of the and interface respectively. Error handling is done in the same way as defined for the stream readers and writers. Instances define the combined interfaces of and classes. They inherit all other methods and attributes from the underlying stream.

Encodings and Unicode Strings are stored internally as sequences of code points in range 0x0- 0x10FFFF. (See for more details about the implementation.) Once a string object is used outside of CPU and memory, endianness and how these arrays are stored as bytes become an issue. As with other codecs, serialising a string into a sequence of bytes is known as encoding, and recreating the string from the sequence of bytes is known as decoding. There are a variety of different text serialisation codecs, which are collectivity referred to as. The simplest text encoding (called 'latin-1' or 'iso-8859-1') maps the code points 0-255 to the bytes 0x0- 0xff, which means that a string object that contains code points above U+00FF can’t be encoded with this codec. Doing so will raise a that looks like the following (although the details of the error message may differ): UnicodeEncodeError: 'latin-1' codec can't encode character ' u1234' in position 3: ordinal not in range(256). There’s another group of encodings (the so called charmap encodings) that choose a different subset of all Unicode code points and how these code points are mapped to the bytes 0x0- 0xff.

To see how this is done simply open e.g. Encodings/cp1252.py (which is an encoding that is used primarily on Windows). There’s a string constant with 256 characters that shows you which character is mapped to which byte value.

All of these encodings can only encode 256 of the 1114112 code points defined in Unicode. A simple and straightforward way that can store each Unicode code point, is to store each code point as four consecutive bytes. There are two possibilities: store the bytes in big endian or in little endian order.

These two encodings are called UTF-32-BE and UTF-32-LE respectively. Their disadvantage is that if e.g. You use UTF-32-BE on a little endian machine you will always have to swap bytes on encoding and decoding. UTF-32 avoids this problem: bytes will always be in natural endianness. When these bytes are read by a CPU with a different endianness, then bytes have to be swapped though. To be able to detect the endianness of a UTF-16 or UTF-32 byte sequence, there’s the so called BOM (“Byte Order Mark”). This is the Unicode character U+FEFF.

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This character can be prepended to every UTF-16 or UTF-32 byte sequence. The byte swapped version of this character ( 0xFFFE) is an illegal character that may not appear in a Unicode text. So when the first character in an UTF-16 or UTF-32 byte sequence appears to be a U+FFFE the bytes have to be swapped on decoding. Unfortunately the character U+FEFF had a second purpose as a ZERO WIDTH NO-BREAK SPACE: a character that has no width and doesn’t allow a word to be split. Be used to give hints to a ligature algorithm. With Unicode 4.0 using U+FEFF as a ZERO WIDTH NO-BREAK SPACE has been deprecated (with U+2060 ( WORD JOINER) assuming this role). Nevertheless Unicode software still must be able to handle U+FEFF in both roles: as a BOM it’s a device to determine the storage layout of the encoded bytes, and vanishes once the byte sequence has been decoded into a string; as a ZERO WIDTH NO-BREAK SPACE it’s a normal character that will be decoded like any other.

There’s another encoding that is able to encoding the full range of Unicode characters: UTF-8. UTF-8 is an 8-bit encoding, which means there are no issues with byte order in UTF-8. Each byte in a UTF-8 byte sequence consists of two parts: marker bits (the most significant bits) and payload bits.

The marker bits are a sequence of zero to four 1 bits followed by a 0 bit. Unicode characters are encoded like this (with x being payload bits, which when concatenated give the Unicode character): Range Encoding U-00000000 U-0000007F 0xxxxxxx U-00000080 U-000007FF 110xxxxx 10xxxxxx U-00000800 U-0000FFFF 1110xxxx 10xxxxxx 10xxxxxx U-00010000 U-0010FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx The least significant bit of the Unicode character is the rightmost x bit. As UTF-8 is an 8-bit encoding no BOM is required and any U+FEFF character in the decoded string (even if it’s the first character) is treated as a ZERO WIDTH NO-BREAK SPACE. Without external information it’s impossible to reliably determine which encoding was used for encoding a string. Each charmap encoding can decode any random byte sequence. However that’s not possible with UTF-8, as UTF-8 byte sequences have a structure that doesn’t allow arbitrary byte sequences. To increase the reliability with which a UTF-8 encoding can be detected, Microsoft invented a variant of UTF-8 (that Python 2.5 calls 'utf-8-sig') for its Notepad program: Before any of the Unicode characters is written to the file, a UTF-8 encoded BOM (which looks like this as a byte sequence: 0xef, 0xbb, 0xbf) is written.

As it’s rather improbable that any charmap encoded file starts with these byte values (which would e.g. INVERTED QUESTION MARK in iso-8859-1), this increases the probability that a utf-8-sig encoding can be correctly guessed from the byte sequence. So here the BOM is not used to be able to determine the byte order used for generating the byte sequence, but as a signature that helps in guessing the encoding. On encoding the utf-8-sig codec will write 0xef, 0xbb, 0xbf as the first three bytes to the file. On decoding utf-8-sig will skip those three bytes if they appear as the first three bytes in the file. In UTF-8, the use of the BOM is discouraged and should generally be avoided. Standard Encodings Python comes with a number of codecs built-in, either implemented as C functions or with dictionaries as mapping tables.

The following table lists the codecs by name, together with a few common aliases, and the languages for which the encoding is likely used. Neither the list of aliases nor the list of languages is meant to be exhaustive. Notice that spelling alternatives that only differ in case or use a hyphen instead of an underscore are also valid aliases; therefore, e.g. 'utf-8' is a valid alias for the 'utf8' codec. CPython implementation detail: Some common encodings can bypass the codecs lookup machinery to improve performance. These optimization opportunities are only recognized by CPython for a limited set of aliases: utf-8, utf8, latin-1, latin1, iso-8859-1, mbcs (Windows only), ascii, utf-16, and utf-32. Using alternative spellings for these encodings may result in slower execution.

Many of the character sets support the same languages. They vary in individual characters (e.g.

Whether the EURO SIGN is supported or not), and in the assignment of characters to code positions. For the European languages in particular, the following variants typically exist:. an ISO 8859 codeset. a Microsoft Windows code page, which is typically derived from a 8859 codeset, but replaces control characters with additional graphic characters. an IBM EBCDIC code page. an IBM PC code page, which is ASCII compatible Codec Aliases Languages ascii 646, us-ascii English big5 big5-tw, csbig5 Traditional Chinese big5hkscs big5-hkscs, hkscs Traditional Chinese cp037 IBM037, IBM039 English cp273 273, IBM273, csIBM273 German.

New in version 3.4. New in version 3.3. Text Encodings The following codecs provide to encoding and to decoding, similar to the Unicode text encodings. Codec Aliases Purpose idna Implements, see also.

Only errors='strict' is supported. Mbcs dbcs Windows only: Encode operand according to the ANSI codepage (CPACP) palmos Encoding of PalmOS 3.5 punycode Implements. Stateful codecs are not supported. Rawunicodeescape Latin-1 encoding with uXXXX and UXXXXXXXX for other code points. Existing backslashes are not escaped in any way. It is used in the Python pickle protocol.

Undefined Raise an exception for all conversions, even empty strings. The error handler is ignored. Unicodeescape Encoding suitable as the contents of a Unicode literal in ASCII-encoded Python source code, except that quotes are not escaped.

Decodes from Latin-1 source code. Beware that Python source code actually uses UTF-8 by default. Unicodeinternal Return the internal representation of the operand.

Stateful codecs are not supported. Changed in version 3.4: accepts any as input for encoding and decoding / bz2codec bz2 Compress the operand using bz2 / hexcodec hex Convert operand to hexadecimal representation, with two digits per byte / quopricodec quopri, quotedprintable, quotedprintable Convert operand to MIME quoted printable with quotetabs=True / uucodec uu Convert the operand using uuencode / zlibcodec zip, zlib Compress the operand using gzip / In addition to, 'base64codec' also accepts ASCII-only instances of for decoding.