Python because of the simplicity of the language, let's write code in the way of human thinking, it's easier for the novice to start, and the old bird can't let go.

To write python (elegant, authentic and neat) code, and to observe the big bull code more often, there are many excellent source codes on Github that are worth reading, such as requests, flask and tornado. Here is my reference to other articles and my own experience to collect some common Python codes Writing, hope to help you develop the habit of writing good code.

01. Variable exchange

Bad

tmp = a
a = b
b = tmp

Pythonic

a,b = b,a

02. List derivation

Bad

my_list = []
for i in range(10):
    my_list.append(i*2)

Pythonic

my_list = [i*2 for i in range(10)]

03. Single line expression

Although list derivation is widely praised for its simplicity and expressiveness.

But there are many expressions that can be written as a single line, which is not a good practice.

Bad

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print 'one'; print 'two'

if x == 1: print 'one'

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

Pythonic

print 'one'
print 'two'

if x == 1:
    print 'one'

cond1 = <complex comparison>
cond2 = <other complex comparison>
if cond1 and cond2:
    # do something

04. Traversal with index

Bad

for i in range(len(my_list)):
    print(i, "-->", my_list[i])

Pythonic

for i,item in enumerate(my_list):
    print(i, "-->",item)

05. Sequence unpacking

Pythonic

a, *rest = [1, 2, 3]
# a = 1, rest = [2, 3]

a, *middle, c = [1, 2, 3, 4]
# a = 1, middle = [2, 3], c = 4

06. String splicing

Bad

letters = ['s', 'p', 'a', 'm']
s=""
for let in letters:
    s += let

Pythonic

letters = ['s', 'p', 'a', 'm']
word = ''.join(letters)

07. True or false judgment

Bad

if attr == True:
    print 'True!'

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

Pythonic

if attr:
    print 'attr is truthy!'

if not attr:
    print 'attr is falsey!'

if attr is None:
    print 'attr is None!'

08. Accessing dictionary elements

Bad

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

Pythonic

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']

09. Operation list

Bad

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a = [3, 4, 5]
b = []
for i in a:
    if i > 4:
        b.append(i)

Pythonic

a = [3, 4, 5]
b = [i for i in a if i > 4]
# Or:
b = filter(lambda x: x > 4, a)

Bad

a = [3, 4, 5]
for i in range(len(a)):
    a[i] += 3

Pythonic

a = [3, 4, 5]
a = [i + 3 for i in a]
# Or:
a = map(lambda i: i + 3, a)

10. File reading

Bad

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

Pythonic

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

11. Code continuation

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

Pythonic

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)

12. Explicit code

Bad

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

Pythonic

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

13. Use placeholders

Pythonic

filename = 'foobar.txt'
basename, _, ext = filename.rpartition('.')

14. Chain comparison

Bad

if age > 18 and age < 60:
    print("young man")

Pythonic

if 18 < age < 60:
    print("young man")

If you understand the chain comparison operation, you should know why the output of the following line of code is False

>>> False == False == True 
False

15. Binocular operation

This reservation. Use as you like.

Bad

if a > 2:
    b = 2
else:
    b = 1
#b = 2

Pythonic

a = 3   

b = 2 if a > 2 else 1
#b = 2