日期时间数据类型及工具
from datetime import datetime
now = datetime.now()
print(now.year,now.month,now.day)
#以毫秒形式存储时间
delta = now - datetime(1992,2,2)
print(delta)
print(delta.days)
#可以在时间戳上加减乘除
from datetime import timedelta
print(delta+timedelta(12))
字符串和datetime转化
#时间转str
time_str = now.strftime('%y-%m-%d')
print(time_str)
#str转时间
time_str2 = datetime.strptime(time_str,'%y-%m-%d')
print(time_str2)
#处理成组日期
data_set = ['2017-1-1','2018-1-1']
pd.to_datetime(data_set)
时间序列基础
time_set = [datetime(2017,1,1),datetime(2017,2,1),datetime(2017,3,1),datetime(2017,4,1),datetime(2017,5,1)]
data = pd.DataFrame(np.arange(5),index=time_set)
data = pd.DataFrame(np.random.randn(1000),index=pd.date_range('1992-2-2',periods=1000))
#也可以做切片
data['1992-3-2':]
