一些优雅的 Python 编码技巧

1、交换赋值

# 不推荐写法
c = a
a = b
b = c

# 推荐写法
a,b = b,a

2、in

# 不推荐写法 
if a == '1' or a == '2' or a == '3':

# 推荐写法
if a in ['1','2','3']:

3、列表中元素进行字符串拼接操作

# 不推荐写法
city = ['shanghai','beijing','shenzheng']
new = ''
for item in city:
    new += item
    
# 推荐写法(好处：不占用内存)
city = ['shanghai','beijing','shenzheng']
new = ''.join(city)

4、遍历列表及其索引

# 不推荐写法
items = 'a b c'.split()
## 方法1
i = 0
for item in items:
    print(i,item)
    i += 1
## 方法2
for i in range(len(items)):
    print(i,item[i])
    
# 推荐写法
items = 'a b c'.split()
for i,item in enumerate(items):
    print(i,item)

5、循环嵌套

# 不推荐写法
for x in list1:
    for y in list2:
        for z in list3:
            ......
            
# 推荐写法 
from itertools import product
for x,y,z in product(list1,list2,list3):
    ......

6、with 打开文件

# 不推荐写法
f = open('test.txt')
try:
    data = f.read()
    ...
finally:
    f.close()
    
# 推荐写法
with open('test.txt') as f:
    date = r.read()
    ......