Python的可读性和简单性是其广受欢迎的两大原因，本文介绍20个常用的Python技巧来提高代码的可读性，并能帮助你节省大量时间，下面的技巧将在你的日常编码练习中非常实用。

1.字符串反转

使用Python切片反转字符串：

# Reversing a string using slicing

my_string = "ABCDE"

reversed_string = my_string[::-1]

print(reversed_string)

# Output

# EDCBA

2.每个单词的第一个字母大写

使用title函数方法：

my_string = "my name is chaitanya baweja"

# using the title() function of string class

new_string = my_string.title()

print(new_string)

# Output

# My Name Is Chaitanya Baweja

3. 字符串查找唯一元素

使用集合的概念查找字符串的唯一元素:

my_string = "aavvccccddddeee"

# converting the string to a set

temp_set = set(my_string)

# stitching set into a string using join

new_string = ''.join(temp_set)

print(new_string)

# output

# cdvae

4.重复打印字符串和列表n次

你可以使用乘法符号（*）打印字符串或列表多次：

n = 3 # number of repetitions

my_string = "abcd"

my_list = [1,2,3]

print(my_string*n)

# abcdabcdabcd

print(my_list*n)

# [1,2,3,1,2,3,1,2,3]

5.列表生成

# Multiplying each element in a list by 2

original_list = [1,2,3,4]

new_list = [2*x for x in original_list]

print(new_list)

# [2,4,6,8]

6.变量交换

a = 1

b = 2

a, b = b, a

print(a) # 2

print(b) # 1

7.字符串拆分为子字符串列表

使用.split()函数：

string_1 = "My name is Chaitanya Baweja"

string_2 = "sample/ string 2"

# default separator ' '

print(string_1.split())

# ['My', 'name', 'is', 'Chaitanya', 'Baweja']

# defining separator as '/'

print(string_2.split('/'))

# ['sample', ' string 2']

8.多个字符串组合为一个字符串

list_of_strings = ['My', 'name', 'is', 'Chaitanya', 'Baweja']

# Using join with the comma separator

print(','.join(list_of_strings))

# Output

# My,name,is,Chaitanya,Baweja

9.检测字符串是否为回文

my_string = "abcba"

if my_string == my_string[::-1]:

    print("palindrome")

else:

    print("not palindrome")

# Output

# palindrome

10. 统计列表中元素的次数

# finding frequency of each element in a list

from collections import Counter

my_list = ['a','a','b','b','b','c','d','d','d','d','d']

count = Counter(my_list) # defining a counter object

print(count) # Of all elements

# Counter({'d': 5, 'b': 3, 'a': 2, 'c': 1})

print(count['b']) # of individual element

# 3

print(count.most_common(1)) # most frequent element

# [('d', 5)]

11.判断两个字符串是否为Anagrams

Anagrams的含义为两个单词中，每个英文单词（不含大小写）出现的次数相同，使用Counter类判断两个字符串是否为Anagrams。

from collections import Counter

str_1, str_2, str_3 = "acbde", "abced", "abcda"

cnt_1, cnt_2, cnt_3  = Counter(str_1), Counter(str_2), Counter(str_3)

if cnt_1 == cnt_2:

    print('1 and 2 anagram')

if cnt_1 == cnt_3:

    print('1 and 3 anagram')

# output

# 1 and 2 anagram

12. 使用try-except-else-block模块

except获取异常处理：

a, b = 1,0

try:

    print(a/b)

    # exception raised when b is 0

except ZeroDivisionError:

    print("division by zero")

else:

    print("no exceptions raised")

finally:

    print("Run this always")

# output

# division by zero

# Run this always

13. 使用枚举函数得到key/value对

my_list = ['a', 'b', 'c', 'd', 'e']

for index, value in enumerate(my_list):

    print('{0}: {1}'.format(index, value))

# 0: a

# 1: b

# 2: c

# 3: d

# 4: e

14.检查对象的内存使用情况

import sys

num = 21

print(sys.getsizeof(num))

# In Python 2, 24

# In Python 3, 28

15.合并字典

dict_1 = {'apple': 9, 'banana': 6}

dict_2 = {'banana': 4, 'orange': 8}

combined_dict = {**dict_1, **dict_2}

print(combined_dict)

# Output

# {'apple': 9, 'banana': 4, 'orange': 8}

16.计算执行一段代码所花费的时间

使用time类计算运行一段代码所花费的时间：

import time

start_time = time.time()

# Code to check follows

for i in range(10**5):

    a, b = 1,2

    c = a+ b

# Code to check ends

end_time = time.time()

time_taken_in_micro = (end_time- start_time)*(10**6)

print(time_taken_in_micro)

# output

# 18770.217895507812

17. 列表展开

from iteration_utilities import deepflatten

# if you only have one depth nested_list, use this

def flatten(l):

  return [item for sublist in l for item in sublist]

l = [[1,2,3],[3]]

print(flatten(l))

# [1, 2, 3, 3]

# if you don't know how deep the list is nested

l = [[1,2,3],[4,[5],[6,7]],[8,[9,[10]]]]

print(list(deepflatten(l, depth=3)))

# [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

18. 列表采样

import random

my_list = ['a', 'b', 'c', 'd', 'e']

num_samples = 2

samples = random.sample(my_list,num_samples)

print(samples)

# [ 'a', 'e'] this will have any 2 random values

19.数字化

将整数转化成数字列表：

num = 123456

# using map

list_of_digits = list(map(int, str(num)))

print(list_of_digits)

# [1, 2, 3, 4, 5, 6]

# using list comprehension

list_of_digits = [int(x) for x in str(num)]

print(list_of_digits)

# [1, 2, 3, 4, 5, 6]

20.检查列表元素的唯一性

检查列表中每个元素是否为唯一的：

def unique(l):

    if len(l)==len(set(l)):

        print("All elements are unique")

    else:

        print("List has duplicates")

unique([1,2,3,4])

# All elements are unique

unique([1,1,2,3])

# List has duplicates