python
Pythonic
zip/unzip
def unzip(tuples):
if tuples:
return [tuple(t[i] for t in tuples) for i, _ in enumerate(tuples[0])]
else:
return []
result:
>>> unzip( ((1, 2), (3, 4), (5, 6)) ) [(1, 3, 5), (2, 4, 6)]
in
long_string = "This is a very long string"
if "long" in long_string:
print("Match found")
dict & counter
>>> from collections import Counter
>>> fruits = ['orange', 'banana', 'apple', 'orange', 'banana']
>>> Counter(fruits)
Counter({'orange': 2, 'banana': 2, 'apple': 1})
enumerate
x = ['a', 'b', 'c']
for index, item in enumerate(x):
print(index, item)
P:
array = [1, 2, 3, 4, 5] for i, e in enumerate(array,0): print i, e #0 1 #1 2 #2 3 #3 4 #4 5
NP:
for i in xrange(len(array)): print i, array[i] #0 1 #1 2 #2 3 #3 4 #4 5
import local module
# A.py
def filter_items(items):
for i in items:
if i < 10:
yield i
# B.py
from A import filter_items as A_filter_items
def filter_items(items):
for i in items:
if i <= 5:
yield i
def do_something(items):
x = A_filter_items(items)
y = filter_items(items)
return (x, y)
args & kwargs
def add(one, two):
return one + two
my_list = [1, 2]
x = add(*my_list) # x = 3
my_dict = {"one": 1, "two": 2}
y = add(**my_dict) #y = 3
itertools
>>> from itertools import zip_longest
>>> x = [1, 2, 3, 4]
>>> y = ['a', 'b', 'c']
>>> for i, j in zip_longest(x, y):
... print(i, j)
...
1 a
2 b
3 c
4 None
one-line python code
>>> my_dict = {key: value for key, value in zip_longest(x,y)}
>>> my_dict
{1: 'a', 2: 'b', 3: 'c', 4: None}
slice
word = #some word
is_palindrome = word.find(word[-1::-1])
chain compare
P:
a = 3 b = 1 1 <= b <= a < 10 #True
NP:
a = 3 b = 1 b >= 1 and b <= a and a < 10 #True
boolean
P:
name = 'Tim' langs = ['AS3', 'Lua', 'C'] info = {'name': 'Tim', 'sex': 'Male', 'age':23 } if name and langs and info: print('All True!') #All True!
NP:
if name != '' and len(langs) > 0 and info != {}: print('All True!') #All True!
reverse
P:
def reverse_str( s ): return s[::-1]
NP:
def reverse_str( s ): t = '' for x in xrange(len(s)-1,-1,-1): t += s[x] return t
join in list
P:
strList = ["Python", "is", "good"] res = ' '.join(strList) #Python is good
NP:
res = '' for s in strList: res += s + ' ' #Python is good #最后还有个多余空格
sum & max & min & time
P:
numList = [1,2,3,4,5] sum = sum(numList) #sum = 15 maxNum = max(numList) #maxNum = 5 minNum = min(numList) #minNum = 1 from operator import mul prod = reduce(mul, numList, 1) #prod = 120 默认值传1以防空列表报错
NP:
sum = 0 maxNum = -float('inf') minNum = float('inf') prod = 1 for num in numList: if num > maxNum: maxNum = num if num < minNum: minNum = num sum += num prod *= num # sum = 15 maxNum = 5 minNum = 1 prod = 120
list comprehensions
P:
l = [x*x for x in range(10) if x % 3 == 0] # l = [0, 9, 36, 81]
NP:
l = [] for x in range(10): if x % 3 == 0: l.append(x*x) # l = [0, 9, 36, 81]
default dict
P:
dic = {'name':'Tim', 'age':23} dic['workage'] = dic.get('workage',0) + 1 # dic = {'age': 23, 'workage': 1, 'name': 'Tim'}
NP:
if 'workage' in dic: dic['workage'] += 1 else: dic['workage'] = 1 # dic = {'age': 23, 'workage': 1, 'name': 'Tim'}
if...else...
P:
for x in xrange(1,5): if x == 5: print 'find 5' break else: print 'can not find 5!' # can not find 5!
NP:
find = False for x in xrange(1,5): if x == 5: find = True print 'find 5' break if not find: print 'can not find 5!' # can not find 5!
ternary operator
P:
a = 3 b = 2 if a > 2 else 1 # b = 2
NP:
if a > 2: b = 2 else: b = 1 # b = 2
dict & zip
P:
keys = ['Name', 'Sex', 'Age'] values = ['Tim', 'Male', 23] dic = dict(zip(keys, values)) # {'Age': 23, 'Name': 'Tim', 'Sex': 'Male'}
NP:
dic = {} for i,e in enumerate(keys): dic[e] = values[i] # {'Age': 23, 'Name': 'Tim', 'Sex': 'Male'}
[!NOTE|label:references:]
numbers
round
>>> str(round(1234.5678, -2))
'1200.0'
>>> str(round(1234.5678, 2))
'1234.57'
integer base
>>> int('10', 0)
10
>>> int('0x10', 0)
16
>>> int('010', 0) # does not work on Python 3.x
8
>>> int('0o10', 0) # Python >=2.6 and Python 3.x
8
>>> int('0b10', 0) # Python >=2.6 and Python 3.x
2
in-place value swapping
>>> a = 10
>>> b = 5
>>> a, b
(10, 5)
>>> a, b = b, a
>>> a, b
(5, 10)
sum
from operator import add
print reduce(add, [1,2,3,4,5,6])
string
multi-line strings
>>> sql = "select * from some_table \
where id > 10"
>>> print sql
select * from some_table where id > 10
or
>>> sql = """select * from some_table where id > 10""" >>> print sql select * from some_table where id > 10
or
>>> sql = ("select * from some_table " # <-- no comma, whitespace at end "where id > 10 " "order by name") >>> print sql select * from some_table where id > 10 order by name
in
>>> 'str' in 'string'
True
>>> 'no' in 'yes'
False
>>>
Join
''.join(list_of_strings)
set
>>> a = set([1,2,3,4])
>>> b = set([3,4,5,6])
>>> a | b # Union
{1, 2, 3, 4, 5, 6}
>>> a & b # Intersection
{3, 4}
>>> a < b # Subset
False
>>> a - b # Difference
{1, 2}
>>> a ^ b # Symmetric Difference
{1, 2, 5, 6}
slice operators
a = [1,2,3,4,5]
>>> a[::2] # iterate over the whole list in 2-increments
[1,3,5]
or
>>> a[::-1] [5,4,3,2,1]
or
>>> a = range(10) >>> a [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> a[:5] = [42] >>> a [42, 5, 6, 7, 8, 9] >>> a[:1] = range(5) >>> a [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> del a[::2] >>> a [1, 3, 5, 7, 9] >>> a[::2] = a[::-2] >>> a [9, 3, 5, 7, 1]
reversed
for i in reversed([1, 2, 3]):
print(i)
backslashes
>>> print repr(r"aaa\"bbb")
'aaa\\"bbb'
or
>>> print repr(r"C:\") SyntaxError: EOL while scanning string literal >>> print repr(r"C:\"") 'C:\\"'
args
Use _
instead of last printed item
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> _
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>>
*args
& **kwargs
>>> g = lambda *args, **kwargs: args[0], kwargs['thing']
>>> g(1, 2, 3, thing='stuff')
(1, 'stuff')
or
def foo(a, b, c): print a, b, c bar = (3, 14, 15) foo(*bar)
function argument unpacking
def draw_point(x, y):
# do some magic
point_foo = (3, 4)
point_bar = {'y': 3, 'x': 2}
draw_point(*point_foo)
draw_point(**point_bar)
conditional assignment
ternary operator
>>> 'ham' if True else 'spam'
'ham'
>>> 'ham' if False else 'spam'
'spam'
or
>>> True and 'ham' or 'spam' 'ham' >>> False and 'ham' or 'spam' 'spam'
or
>>> [] if True else 'spam' [] >>> True and [] or 'spam' 'spam'
or
In [18]: a = True In [19]: a and 3 or 4 Out[19]: 3 In [20]: a = False In [21]: a and 3 or 4 Out[21]: 4
or
>>> (1 and [foo()] or [bar()])[0] foo 0
or
>>> foo() if True or bar() foo 0
conditional
x = 3 if (y == 1) else 2
or
x = 3 if (y == 1) else 2 if (y == -1) else 1
or
(func1 if y == 1 else func2)(arg1, arg2)
or
x = (class1 if y == 1 else class2)(arg1, arg2)
or
[(x, y) for x in range(4) if x % 2 == 1 for y in range(4)] [(1, 0), (1, 1), (1, 2), (1, 3), (3, 0), (3, 1), (3, 2), (3, 3)]
or
x = 3 if (y == 1) else 2 is equvalent to x = y == 1 and 3 or 2 x = 0 if True else 1 is equvalent to x = True and 0 or 1
or
foo = [x for x in xrange(10) if x % 2 == 0]
equal to
foo = [] for x in xrange(10): if x % 2 == 0: foo.append(x)
>>> {i: i**2 for i in range(5)}
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
set comprehensions
>>> {i**2 for i in range(5)}
set([0, 1, 4, 16, 9])
list & dics
zip
a = [(1,2), (3,4), (5,6)]
zip(*a)
# [(1, 3, 5), (2, 4, 6)]
or
>>> dict([ ('foo','bar'),('a',1),('b',2) ]) {'a': 1, 'b': 2, 'foo': 'bar'} >>> names = ['Bob', 'Marie', 'Alice'] >>> ages = [23, 27, 36] >>> dict(zip(names, ages)) {'Alice': 36, 'Bob': 23, 'Marie': 27}
or
>>> t1 = (0,1,2,3) >>> t2 = (7,6,5,4) >>> [t1,t2] == zip(*zip(t1,t2)) True
or
In [15]: t1 = (1, 2, 3) In [16]: t2 = (4, 5, 6) In [17]: dict (zip(t1,t2)) Out[17]: {1: 4, 2: 5, 3: 6}
or
>>> l=[(1,2),(3,4)] >>> [a+b for a,b in l ] [3,7]
list & sum
>>> l = [[1, 2, 3], [4, 5], [6], [7, 8, 9]]
>>> sum(l, [])
[1, 2, 3, 4, 5, 6, 7, 8, 9]
nested list
[(i,j) for i in range(3) for j in range(i) ]
or
((i,j) for i in range(4) for j in range(i) )
enumerate
>>> a = ['a', 'b', 'c', 'd', 'e']
>>> for index, item in enumerate(a): print index, item
...
0 a
1 b
2 c
3 d
4 e
or
>>> l = ["spam", "ham", "eggs"] >>> list(enumerate(l)) >>> [(0, "spam"), (1, "ham"), (2, "eggs")] >>> list(enumerate(l, 1)) >>> [(1, "spam"), (2, "ham"), (3, "eggs")]
generate list
>>> from functools import partial
>>> bound_func = partial(range, 0, 10)
>>> bound_func()
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> bound_func(2)
[0, 2, 4, 6, 8]
dict's constructor
>>> dict(foo=1, bar=2)
{'foo': 1, 'bar': 2}
or
>>> a = {} >>> b = a.setdefault('foo', 'bar') >>> a {'foo': 'bar'} >>> b 'bar
dict's get
t = {1: 'a'}
>>> test[2]
Traceback (most recent call last):
File "<pyshell#158>", line 1, in <module>
test[2]
KeyError: 2
>>> test.get(2)
>>> test.get(1)
'a'
>>> test.get(2) == None
True
>>> test.get(2, 'some') == 'some'
True
copy list
>>> x = [1,2,3]
>>> y = x[:]
>>> y.pop()
3
>>> y
[1, 2]
>>> x
[1, 2, 3]
replace list
>>> x = [1,2,3]
>>> y = x
>>> y[:] = [4,5,6]
>>> x
[4, 5, 6]
generators objects
x = [n for n in foo if bar(n)]
or
>>> n = ((a,b) for a in range(0,2) for b in range(4,6)) >>> for i in n: ... print i (0, 4) (0, 5) (1, 4) (1, 5)
generator & iteration
iteration & constructor (yield)
>>> def g(n):
... for i in range(n):
... yield i **2
>>> t = g(5)
>>> t.next()
0
>>> t.next()
1
>>> t.next()
4
>>> t.next()
9
>>> t.next()
16
>>> t.next()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
or
def fab(max): a,b = 0,1 while a < max: yield a a, b = b, a+b >>> for i in fab(20): ... print i,",", ... 0 , 1 , 1 , 2 , 3 , 5 , 8 , 13 ,
or
>>> i = (1,2,3,4,5,6,7,8,9,10) # or any iterable object >>> iterators = [iter(i)] * 2 >>> iterators[0].next() 1 >>> iterators[1].next() 2 >>> iterators[0].next() 3
or
def grouper(n, iterable, fillvalue=None): "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx" args = [iter(iterable)] * n return izip_longest(fillvalue=fillvalue, *args)
or
>>> from itertools import * >>> l = [[1, 2], [3, 4]] >>> list(chain(*l)) [1, 2, 3, 4]
or
def create_printers(n): for i in xrange(n): def printer(i=i): # Doesn't work without the i=i print i yield printer
statement
for...else...
for i in foo:
if i == 0:
break
else:
print("i was never 0")
or
found = False for i in foo: if i == 0: found = True break if not found: print("i was never 0")
context managers and the "with" statement
from __future__ import with_statement
with open('foo.txt', 'w') as f:
f.write('hello!')
try...except...elese...finally
try:
put_4000000000_volts_through_it(parrot)
except Voom:
print "'E's pining!"
else:
print "This parrot is no more!"
finally:
end_sketch()
funcs
dir
>>> dir("foo")
['__add__', '__class__', '__contains__', (snipped a bunch), 'title',
'translate', 'upper', 'zfill']
help
>>> help("foo".upper)
Help on built-in function upper:
upper(...)
S.upper() -> string
Return a copy of the string S converted to uppercase.
convenient web-browser controller
>>> import webbrowser
>>> webbrowser.open_new_tab('http://www.stackoverflow.com')
built-in http server
python -m SimpleHTTPServer 8000
an interpreter within the interpreter
$ python
Python 2.5.1 (r251:54863, Jan 17 2008, 19:35:17)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> shared_var = "Set in main console"
>>> import code
>>> ic = code.InteractiveConsole({ 'shared_var': shared_var })
>>> try:
... ic.interact("My custom console banner!")
... except SystemExit, e:
... print "Got SystemExit!"
...
My custom console banner!
>>> shared_var
'Set in main console'
>>> shared_var = "Set in sub-console"
>>> import sys
>>> sys.exit()
Got SystemExit!
>>> shared_var
'Set in main console'
pretty print
>>> import pprint
>>> stuff = sys.path[:]
>>> stuff.insert(0, stuff)
>>> pprint.pprint(stuff)
[<Recursion on list with id=869440>,
'',
'/usr/local/lib/python1.5',
'/usr/local/lib/python1.5/test',
'/usr/local/lib/python1.5/sunos5',
'/usr/local/lib/python1.5/sharedmodules',
'/usr/local/lib/python1.5/tkinter']
or
from __future__ import print_function mylist = ['foo', 'bar', 'some other value', 1,2,3,4] print(*mylist)
class & module
bash
python -c"import os; print(os.getcwd());"
assertion
>>> try:
... assert []
... except AssertionError:
... print "This list should not be empty"
This list should not be empty
import
try:
import json
except ImportError:
import simplejson as json
create new types
>>> NewType = type("NewType", (object,), {"x": "hello"})
>>> n = NewType()
>>> n.x
"hello"
or
>>> class NewType(object): >>> x = "hello" >>> n = NewType() >>> n.x "hello"
Manipulating sys.modules
>>> import sys
>>> import ham
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named ham
# Make the 'ham' module available -- as a non-module object even!
>>> sys.modules['ham'] = 'ham, eggs, saussages and spam.'
>>> import ham
>>> ham
'ham, eggs, saussages and spam.'
# Now remove it again.
>>> sys.modules['ham'] = None
>>> import ham
Traceback (most recent call last):
or
>>> import os # Stop future imports of 'os'. >>> sys.modules['os'] = None >>> import os Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named os # Our old imported module is still available. >>> os <module 'os' from '/usr/lib/python2.5/os.pyc'>
Others
not hidden but still nice
import os.path as op
root_dir = op.abspath(op.join(op.dirname(__file__), ".."))
be careful with mutable default arguments
>>> def foo(x=[]):
... x.append(1)
... print x
...
>>> foo()
[1]
>>> foo()
[1, 1]
>>> foo()
[1, 1, 1]
or
>>> def foo(x=None): ... if x is None: ... x = [] ... x.append(1) ... print x >>> foo() [1] >>> foo() [1]
Indentation
yes:
# Aligned with opening delimiter. foo = long_function_name(var_one, var_two, var_three, var_four) # More indentation included to distinguish this from the rest. def long_function_name( var_one, var_two, var_three, var_four): print(var_one) # Hanging indents should add a level. foo = long_function_name( var_one, var_two, var_three, var_four)
no:
# Arguments on first line forbidden when not using vertical alignment. foo = long_function_name(var_one, var_two, var_three, var_four) # Further indentation required as indentation is not distinguishable. def long_function_name( var_one, var_two, var_three, var_four): print(var_one)
optional
# Hanging indents *may* be indented to other than 4 spaces.
foo = long_function_name(
var_one, var_two,
var_three, var_four)
if
statemant
# No extra indentation.
if (this_is_one_thing and
that_is_another_thing):
do_something()
# Add a comment, which will provide some distinction in editors
# supporting syntax highlighting.
if (this_is_one_thing and
that_is_another_thing):
# Since both conditions are true, we can frobnicate.
do_something()
# Add some extra indentation on the conditional continuation line.
if (this_is_one_thing
and that_is_another_thing):
do_something()o
list
my_list = [
1, 2, 3,
4, 5, 6,
]
result = some_function_that_takes_arguments(
'a', 'b', 'c',
'd', 'e', 'f',
)
or
my_list = [ 1, 2, 3, 4, 5, 6, ] result = some_function_that_takes_arguments( 'a', 'b', 'c', 'd', 'e', 'f', )
Maximum Line Length
yes:
with open('/path/to/some/file/you/want/to/read') as file_1, \ open('/path/to/some/file/being/written', 'w') as file_2: file_2.write(file_1.read())
Should a Line break before or after a binary operator?
no: operators sit far away from their operands
income = (gross_wages + taxable_interest + (dividends - qualified_dividends) - ira_deduction - student_loan_interest)
yes: easy to match operators with operands
income = (gross_wages + taxable_interest + (dividends - qualified_dividends) - ira_deduction - student_loan_interest)
imports
no:
import sys, os
yes:
import os import sys
bad:
import <module> from *
absolute imports are recommended
import mypkg.sibling
from mypkg import silbing
from mypkg.sibling import example
explicit relative imports are acceptable
from . import sibling
from .sibling import example
import a class from a class-containing module
from myclass import MyClass
from foo.bar.yourclass import YourClass
local name classes
import myclass
import foo.bar.yourclass
# use "myclass.MyClass" or "foo.bar.yourclass.YourClass"
module Level dunder names
yes:
"""This is the example module. This module does stuff. """ from __future__ import barry_as_FLUFL __all__ = ['a', 'b', 'c'] __version__ = '0.1' __author__ = 'Cardinal Biggles' import os import sys
whitespace in expressions and statements
no:
spam( ham[ 1 ], { eggs: 2 } )
yes:
spam(ham[1], {eggs: 2})
no:
if x == 4 : print x , y ; x , y = y , x
yes:
if x == 4; print x, y; x, y = y, x
no:
ham[lower + offset:upper + offset] ham[1: 9], ham[1 :9], ham[1:9 :3] ham[lower : : upper] ham[ : upper ]
yes:
ham[1:9], ham[1:9:3], ham[:9:3], ham[1::3], ham[1:9:] ham[lower:upper], ham[lowser:pper:], ham[lower::step] ham[lower+offset : upper+offset] ham[: upper_fn(x) : setp_fn(x)], ham[:: setp_fn(x)] ham[lower + offset : upper + offset]
no:
spam (1)
yes:
spam(1)
no:
dct ['key'] = lst [index]
yes:
dct['key'] = lst[index]
no:
x = 1 y = 2 long_variable = 3
yes:
x = 1 y = 2 long_variable = 3
other recommendations
no:
i=i+1 submitted +=1 x = x * 2 - 1 hypot2 = x * x + y * y c = (a + b) * (a - b)
yes:
i = i + 1 submitted += 1 x = x*2 - 1 hypot2 = x*x + y*y c = (a+b) * (a-b)
no:
def complex(real, imag = 0.0): return magic(r = real, i = imag)
yes:
def complex(real, imag=0.0): return magic(r=real, i=imag)
no:
def munge(input:AnyStr): ... def munge()->PosInt: ...
yes:
def munge(input: AnyStr): ... def munge() -> AnyStr: ...
no:
def munge(input: AnyStr=None): ... def munge(input: AnyStr, limit = 1000): ...
yes:
def munge(sep: AnyStr = None): ... def munge(input: AnyStr, sep: AnyStr = None, limit=1000): ...
rather NO
if foo == 'blah': do_blah_thing()
do_one(); do_two(); do_three()
yes:
if foo == 'blah': do_blah_thing() do_one() do_two() do_three()
DEFINITELY NO
if foo == 'blah': do_blah_thing()
else: do_non_blah_thing()
try: something()
finally: cleanup()
do_one(); do_two(); do_three(long, argument,
list, like, this)
if foo == 'blah': one(); two(); three()
yes:
if foo == 'blah': do_blah_thing() for x in lst: total += x while t < 10: t = delay()
documentation strings
yes:
"""Return a foobang Optional plotz says to frobnicate the bizbaz first. """
Programming Recommendations
no:
if not foo is None:
yes:
if foo is not None:
no:
f = lambda x: 2*x
yes:
def f(x): return 2*x
no:
try: # Too broad! return handle_value(collection[key]) expect KeyError: # Will also catch KeyError raised by handle_value() return key_not_found(key)
yes:
try: value = collection[key] except KeyError: return key_not_found(key) else: return handle_value(value)
no:
with conn: do_stuff_in_transaction(conn)
yes:
with conn.begin_transaction(): do_stuff_in_transaction(conn)
no:
def foo(x): fi x >= 0: return math.sqrt(x) def bar(x): if x < 0: return return math.sqrt(x)
yes:
def foo(x): if x >= 0: return math.sqrt(x) else: return None def bar(x): if x < 0: return None return math.sqrt(x)
no:
if foo[:3] == 'bar':
yes:
if foo.startwith('bar'):
no:
if type(obj) is type(1):
yes:
if isinstance(obj, int):
no:
if len(seq): if not len(seq):
yes:
if not seq: if seq:
no:
if greeting == True:
yes:
if greeting:
worse:
if greeting is True:
E1 Indentation
E101 indentation contains mixed spaces and tabs
E111 indentation is not a multiple of four
E112 expected an indented block
E113 unexpected indentation
E114 indentation is not a multiple of four (comment)
E115 expected an indented block (comment)
E116 unexpected indentation (comment)
E121 (*^) continuation line under-indented for hanging indent
E122 (^) continuation line missing indentation or outdented
E123 (*) closing bracket does not match indentation of opening bracket’s line
E124 (^) closing bracket does not match visual indentation
E125 (^) continuation line with same indent as next logical line
E126 (*^) continuation line over-indented for hanging indent
E127 (^) continuation line over-indented for visual indent
E128 (^) continuation line under-indented for visual indent
E129 (^) visually indented line with same indent as next logical line
E131 (^) continuation line unaligned for hanging indent
E133 (*) closing bracket is missing indentation
E2 Whitespace
E201 whitespace after ‘(‘
E202 whitespace before ‘)’
E203 whitespace before ‘:’
E211 whitespace before ‘(‘
E221 multiple spaces before operator
E222 multiple spaces after operator
E223 tab before operator
E224 tab after operator
E225 missing whitespace around operator
E226 (*) missing whitespace around arithmetic operator
E227 missing whitespace around bitwise or shift operator
E228 missing whitespace around modulo operator
E231 missing whitespace after ‘,’, ‘;’, or ‘:’
E241 (*) multiple spaces after ‘,’
E242 (*) tab after ‘,’
E251 unexpected spaces around keyword / parameter equals
E261 at least two spaces before inline comment
E262 inline comment should start with ‘# ‘
E265 block comment should start with ‘# ‘
E266 too many leading ‘#’ for block comment
E271 multiple spaces after keyword
E272 multiple spaces before keyword
E273 tab after keyword
E274 tab before keyword
E3 Blank line
E301 expected 1 blank line, found 0
E302 expected 2 blank lines, found 0
E303 too many blank lines (3)
E304 blank lines found after function decorator
E4 Import
E401 multiple imports on one line
E402 module level import not at top of file
E5 Line length
E501 (^) line too long (82 > 79 characters)
E502 the backslash is redundant between brackets
E7 Statement
E701 multiple statements on one line (colon)
E702 multiple statements on one line (semicolon)
E703 statement ends with a semicolon
E704 (*) multiple statements on one line (def)
E711 (^) comparison to None should be ‘if cond is None:’
E712 (^) comparison to True should be ‘if cond is True:’ or ‘if cond:’
E713 test for membership should be ‘not in’
E714 test for object identity should be ‘is not’
E721 (^) do not compare types, use ‘isinstance()’
E731 do not assign a lambda expression, use a def
E9 Runtime
E901 SyntaxError or IndentationError
E902 IOError
W1 Indentation warning
W191 indentation contains tabs
W2 Whitespace warning
W291 trailing whitespace
W292 no newline at end of file
W293 blank line contains whitespace
W3 Blank line warning
W391 blank line at end of file
W5 Line break warning
W503 line break occurred before a binary operator
W6 Deprecation warning
W601 .has_key() is deprecated, use ‘in’
W602 deprecated form of raising exception
W603 ‘<>’ is deprecated, use ‘!=’
W604 backticks are deprecated, use ‘repr()’
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