Code Style

◉ 암묵적 코드

Bad

def make_complex(*args):
    x, y = args
    return dict(**locals())

Good

def make_complex(x, y):
    return {'x': x, 'y': y}

◉ 한 라인에 한 문장

Bad

print('one'); print('two')

if x == 1: print 'one'

if <complex comparison> and <other complex comparison>:
    # do something

Good

print('one')
print('two')

if x == 1:
    print('one')

cond1 = <complex comparison>
cond2 = <other complex comparison>

if cond1 and cond2:
    # do something

Conventions

◉ 상수일 경우 확인

Bad

if attr == True:
    print('True!')

if attr == None:
    print('attr is None!')

Good

# Just check the value
if attr:
    print('attr is true!')

# or check for the opposite
if not attr:
    print('attr is false!')

# or, since None is considered false, explicitly check for it
if attr is None:
    print('attr is None!')

◉ 사전 요소 접근

Bad

d = {'hello': 'world'}
if d.has_key('hello'):
    print(d['hello'])    # prints 'world'
else:
    print('default_value')

Good

d = {'hello': 'world'}

print(d.get('hello', 'default_value')) # prints 'world'
print(d.get('thingy', 'default_value')) # prints 'default_value'

# Or:
if 'hello' in d:
    print(d['hello'])

◉ 리스트 짧게 쓰기

리스트 함축은 강력하다. 이를 잘 활용하면 리스트를 짧게 쓸 수 있다.

Bad

# Filter elements greater than 4
a = [3, 4, 5]
b = []
for i in a:
    if i > 4:
        b.append(i)

Good

a = [3, 4, 5]
b = [i for i in a if i > 4]

# Or:

b = filter(lambda x: x > 4, a)

Bad

# Add three to all list members.
a = [3, 4, 5]
for i in range(len(a)):
    a[i] += 3

Good

a = [3, 4, 5]
a = [i + 3 for i in a]

# Or:

a = map(lambda i: i + 3, a)

# enumerate()를 사용하면 list의 인덱스를 알려준다.
a = [3, 4, 5]

for i, item in enumerate(a):
    print i, item

# prints
# 0 3
# 1 4
# 2 5

◉ 파일로부터 읽기

Bad

f = open('file.txt')
a = f.read()
print(a)
f.close()

Good

with open('file.txt') as f:
    for line in f:
        print line

◉ 라인 이어쓰기

Bad

my_very_big_string = """For a long time I used to go to bed early. Sometimes, \
    when I had put out my candle, my eyes would close so quickly that I had not even \
    time to say “I’m going to sleep.”"""

from some.deep.module.inside.a.module import a_nice_function, another_nice_function, \
    yet_another_nice_function

Good

my_very_big_string = (
    "For a long time I used to go to bed early. Sometimes, "
    "when I had put out my candle, my eyes would close so quickly "
    "that I had not even time to say “I’m going to sleep.”"
)

from some.deep.module.inside.a.module import (
    a_nice_function, another_nice_function, yet_another_nice_function)