案例：规范时间序列1

import os
os.chdir('C:\\Users\\Sonia\\Desktop\\')  #切换文件目录

#将时间转换为mins.secs的格式
def sanitize(time_string):
    if '-' in time_string:
        splitter = '-'
        
    elif ':' in time_string:
        splitter = ':'

    else:
        return(time_string)

    (mins,secs) = time_string.split(splitter)
    return(mins + '.' + secs)

def read(filename,separator = ','):
    try:
        with open(filename,"r") as file:
            data = file.readline()
            lists = data.strip().split(separator)    #方法串链，从左向右对data进行处理

        #以下代码可以合并为推导列表①
        #clean_list = []
        #for each_item in lists:
        #    clean_list.append(sanitize(each_item))
        clean_list = [sanitize(each_item) for each_item in lists]       #推导列表①
        print('clean_list:'+str(clean_list))


        #order_list = sorted(clean_list)②
        order_list = sorted(sanitize(each_item) for each_item in lists)     #推导列表②
        print('order_list:'+str(order_list))


        #以下代码可以合并为推导列表③
        #unique_list = []
        #for each_item in order_list:
        #   if each_item not in unique_list:
        #        unique_list.append(each_item)
        unique_list =sorted(set(order_list))         #推导列表③
        #如果不加sorted，直接用set会乱序
        unique_list:['2.01', '2.22', '2.34', '2.45', '3.01', '3.10', '3.21']
        unique_list2:{'3.21', '3.01', '2.22', '3.10', '2.01', '2.45', '2.34'}'''
        print('unique_list:'+str(unique_list))


        #①②③可以合并成推到列表④
        print('推导列表④：'+str(sorted(set(sanitize(each_item) for each_item in lists))))   #推导列表④
        print(unique_list[0:3])

    except IOError as err:
        print('File Error:' + str(err))
        return(None)
  
james = read('james.txt')