python 常用方法积累

• operator.itemgetter

  
  
  屏幕快照 2018-07-31 下午5.22.57.png

在排序中也很常用

屏幕快照 2018-07-31 下午5.25.51.png

• 随机值

from random import choice
from random import randint
a = choice([1,2,3,4,5])  # a是该列表中的任意一个
b = randint(1,5)   #b是1~5之间的任意整数

• 读取文件

file_name1 = "...."
file_name2 = "..."
with open(file_name1)  as f0:
    for line in f0:
         print line
with open(file_name1) as f1:
    reader = csv.reader(f1)
    for index,line in enumerate(reader)
              print line

with open(file_name2) as f2:
     j_data = json.load(f2)
     for  j_dict in j_data:
           ....

• 查找 list中的重复元素

some_list = ['a','b','a','a']
duplicate = set([ x for x in some_list if some_list.count(x) >1])

• 利用enumerate创建包含 指定索引值起始值的 元组列表

list_1 =['a','b','c']
list_2 = list(enumerate(list_1,1))
list_2 # [(1,'a'),(2,'b'),(3,'c')]