Porting code to Python 3 with `2to3`

Diving in
print statement
<> comparison
has_key() dictionary method
Dictionary methods
Modules that have been renamed or reorganized
filter() global function
map() global function
apply() global function
intern() global function
exec statement
repr literals (backticks)
try...except statement
raise statement
throw statement
long data type
xrange() global function
raw_input() and input() global functions
func_* function attributes
xreadlines() I/O method
lambda functions with multiple parameters
__class__ special class attribute
next() iterator method
__nonzero__ special class attribute
Number literals
sys.maxint
unicode() global function
Unicode string literals
callable() global function
zip() global function
StandardError() exception
types module constants
basestring datatype
itertools module
Relative imports
sys.exc_type, sys.exc_value, sys.exc_traceback
List comprehensions over tuples
os.getcwdu() function
Metaclasses
set() literals
buffer() global function
Whitespace around commas
Common idioms

Diving in

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`print` statement

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Notes	Python 2	Python 3
①	`print`	`print()`
②	`print 1`	`print(1)`
③	`print 1, 2`	`print(1, 2)`
④	`print 1, 2,`	`print(1, 2, end=' ')`
⑤	`print >>sys.stderr, 1, 2, 3`	`print(1, 2, 3, file=sys.stderr)`

<> comparison

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Notes	Python 2	Python 3
①	`if x <> y:`	`if x != y:`
②	`if x <> y <> z:`	`if x != y != z:`

`has_key()` dictionary method

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Notes	Python 2	Python 3
①	`aDictionary.has_key("PapayaWhip")`	`"PapayaWhip" in aDictionary`
②	`aDictionary.has_key(x) or aDictionary.has_key(y)`	`x in aDictionary or y in aDictionary`
③	`aDictionary.has_key(x + y)`	`(x + y) in aDictionary`
④	`x + aDictionary.has_key(y)`	`x + (y in aDictionary)`
⑤	`aDictionary.has_key(x or y)`	`(x or y) in aDictionary`

Dictionary methods

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Notes	Python 2	Python 3
①	`aDictionary.keys()`	`list(aDictionary.keys())`
②	`aDictionary.items()`	`list(aDictionary.items())`
③	`aDictionary.iterkeys()`	`iter(aDictionary.keys())`
④	`[i for i in aDictionary.iterkeys()]`	`[i for i in aDictionary.keys()]`
⑤	`min(aDictionary.keys())`	no change

Modules that have been renamed or reorganized

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Notes	Python 2	Python 3
①	`import StringIO import cStringIO`	`import io`
②	`import cPickle`	`import pickle`
③	`import __builtin__`	`import builtins`
④	`import copy_reg`	`import copyreg`
⑤	`import Queue`	`import queue`
⑥	`import SocketServer`	`import socketserver`
⑦	`import ConfigParser`	`import configparser`
⑧	`import repr`	`import reprlib`
⑨	`import commands`	`import subprocess`

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Notes	Python 2	Python 3
①	`import dbm`	`import dbm.ndbm`
②	`import gdbm`	`import dbm.gnu`
③	`import dbhash`	`import dbm.bsd`
④	`import dumbdbm`	`import dbm.dumb`
⑤	`import anydbm import whichdb`	`import dbm`

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Notes	Python 2	Python 3
①	`import xmlrpclib`	`import xmlrpc.client`
②	`import DocXMLRPCServer import SimpleXMLRPCServer`	`import xmlrpc.server`

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Notes	Python 2	Python 3
①	`import httplib`	`import http.client`
②	`import Cookie`	`import http.cookies`
③	`import cookielib`	`import http.cookiejar`
④	`import BaseHTTPServer import SimpleHTTPServer import CGIHttpServer`	`import http.server`

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Notes	Python 2	Python 3
①	`import urllib`	`import urllib.request, urllib.parse, urllib.error`
②	`import urllib2`	`import urllib.request, urllib.error`
③	`import urlparse`	`import urllib.parse`
④	`import robotparser`	`import urllib.robotparser`
⑤	`from urllib import FancyURLOpener from urllib import urlencode`	`from urllib.request import FancyURLOpener from urllib.parse import urlencode`
⑥	`from urllib2 import Request from urllib2 import HTTPError`	`from urllib.request import Request from urllib.error import HTTPError`

`filter()` global function

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Notes	Python 2	Python 3
①	`filter(aFunction, aList)`	`list(filter(aFunction, aList))`
②	`list(filter(aFunction, aList))`	no change
③	`filter(None, aList)`	`[i for i in aList if i]`
④	`for i in filter(None, aList)`	no change
⑤	`[i for i in filter(aFunction, aList)]`	no change

`map()` global function

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Notes	Python 2	Python 3
①	`map(aFunction, 'PapayaWhip')`	`list(map(aFunction, 'PapayaWhip'))`
②	`map(None, 'PapayaWhip')`	`list('PapayaWhip')`
③	`map(lambda x: x+1, range(42))`	`[x+1 for x in range(42)]`
④	`for i in map(aFunction, aList):`	unchanged
⑤	`[i for i in map(aFunction, aList)]`	unchanged

`apply()` global function

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Notes	Python 2	Python 3
①	`apply(aFunction, args)`	`aFunction(*args)`
②	`apply(aFunction, args, kwds)`	`aFunction(args, *kwds)`
③	`apply(aFunction, args + z)`	`aFunction(*args + z)`
④	`apply(aModule.aFunction, args)`	`aModule.aFunction(*args)`

`intern()` global function

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Notes	Python 2	Python 3
①	`intern(aString)`	`sys.intern(aString)`

`exec` statement

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Notes	Python 2	Python 3
①	`exec codeString`	`exec(codeString)`
②	`exec codeString in aGlobalNamespace`	`exec(codeString, aGlobalNamespace)`
③	`exec codeString in aGlobalNamespace, aLocalNamespace`	`exec(codeString, aGlobalNamespace, aLocalNamespace)`

`repr` literals (backticks)

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Notes	Python 2	Python 3
①	`x`	`repr(x)`
②	`1 + 2`	`repr(1 + 2)`
③	`"PapayaWhip" + `2``	`repr("PapayaWhip" + repr(2))`

`try...except` statement

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Notes	Python 2	Python 3
①	`try: import mymodule except ImportError, e pass`	`try: import mymodule except ImportError as e: pass`
②	`try: import mymodule except (RuntimeError, ImportError), e pass`	`try: import mymodule except (RuntimeError, ImportError) as e: pass`
③	`try: import mymodule except ImportError: pass`	unchanged
④	`try: import mymodule except: pass`	unchanged

`raise` statement

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Notes	Python 2	Python 3
①	`raise MyException, "error message"`	`raise MyException("error message")`
②	`raise MyException, "error message", aTraceback`	`raise MyException("error message").with_traceback(aTraceback)`
③	`raise "error message"`	unsupported

`throw` statement

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Notes	Python 2	Python 3
①	`aGenerator.throw(MyException)`	unchanged
②	`aGenerator.throw(MyException, "error message")`	`aGenerator.throw(MyException("error message"))`
③	`aGenerator.throw("error message")`	unsupported

`long` data type

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Notes	Python 2	Python 3
①	`x = 1000000000000L`	`x = 1000000000000`
②	`x = 0xFFFFFFFFFFFFL`	`x = 0xFFFFFFFFFFFF`
③	`long(x)`	`int(x)`
④	`type(x) is long`	`type(x) is int`
⑤	`isinstance(x, long)`	`isinstance(x, int)`

`xrange()` global function

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Notes	Python 2	Python 3
①	`xrange(10)`	`range(10)`
②	`aList = range(10)`	`aList = list(range(10))`
③	`[i for i in xrange(10)]`	`[i for i in range(10)]`
④	`for i in range(10):`	unchanged
⑤	`sum(range(10))`	unchanged

`raw_input()` and `input()` global functions

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Notes	Python 2	Python 3
①	`raw_input()`	`input()`
②	`raw_input("prompt")`	`input("prompt")`
③	`input()`	`eval(input())`
④	`input("prompt")`	`eval(input("prompt"))`

`func_*` function attributes

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Notes	Python 2	Python 3
①	`aFunction.func_closure`	`aFunction.__closure__`
②	`aFunction.func_doc`	`aFunction.__doc__`
③	`aFunction.func_name`	`aFunction.__name__`
④	`aFunction.func_defaults`	`aFunction.__defaults__`
⑤	`aFunction.func_code`	`aFunction.__code__`
⑥	`aFunction.func_globals`	`aFunction.__globals__`
⑦	`aFunction.func_dict`	`aFunction.__dict__`

`xreadlines()` I/O method

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Notes	Python 2	Python 3
①	`for line in aFile.xreadlines():`	`for line in aFile:`
②	`for line in aFile.xreadlines(5):`	unchanged

`lambda` functions with multiple parameters

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`class` special class attribute

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`next()` iterator method

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`nonzero` special class attribute

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Number literals

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`sys.maxint`

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`unicode()` global function

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Unicode string literals

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`callable()` global function

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`zip()` global function

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`StandardError()` exception

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`types` module constants

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`basestring` datatype

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`itertools` module

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this includes fixer_itertools, fixer_itertools_imports

Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Relative imports

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`sys.exc_type`, `sys.exc_value`, `sys.exc_traceback`

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

List comprehensions over tuples

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`os.getcwdu()` function

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Metaclasses

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`set()` literals

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

`buffer()` global function

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Whitespace around commas

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Common idioms

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Notes	Python 2	Python 3
①	`FIXME`	`FIXME`

Porting code to Python 3 with 2to3

Diving in

print statement

<> comparison

has_key() dictionary method

Dictionary methods

Modules that have been renamed or reorganized

filter() global function

map() global function

apply() global function

intern() global function

exec statement

repr literals (backticks)

try...except statement

raise statement

throw statement

long data type

xrange() global function

raw_input() and input() global functions

func_* function attributes

xreadlines() I/O method

lambda functions with multiple parameters

__class__ special class attribute

next() iterator method

__nonzero__ special class attribute

Number literals

sys.maxint

unicode() global function

Unicode string literals

callable() global function

zip() global function

StandardError() exception

types module constants

basestring datatype

itertools module

Relative imports

sys.exc_type, sys.exc_value, sys.exc_traceback

List comprehensions over tuples

os.getcwdu() function

Metaclasses

set() literals

buffer() global function

Whitespace around commas

Common idioms

Porting code to Python 3 with `2to3`

`print` statement

`has_key()` dictionary method

`filter()` global function

`map()` global function

`apply()` global function

`intern()` global function

`exec` statement

`repr` literals (backticks)

`try...except` statement

`raise` statement

`throw` statement

`long` data type

`xrange()` global function

`raw_input()` and `input()` global functions

`func_*` function attributes

`xreadlines()` I/O method

`lambda` functions with multiple parameters

`class` special class attribute

`next()` iterator method

`nonzero` special class attribute

`sys.maxint`

`unicode()` global function

`callable()` global function

`zip()` global function

`StandardError()` exception

`types` module constants

`basestring` datatype

`itertools` module

`sys.exc_type`, `sys.exc_value`, `sys.exc_traceback`

`os.getcwdu()` function

`set()` literals

`buffer()` global function