Pandas生成时间序列:
import pandas as pd import numpy as np
时间序列
- 时间戳(timestamp)
- 固定周期(period)
- 时间间隔(interval)
date_range
- 可以指定开始时间与周期
- H:小时
- D:天
M:月
# TIMES的几种书写方式 #2016 Jul 1; 7/1/2016; 1/7/2016 ;2016-07-01; 2016/07/01 rng = pd.date_range(‘2016-07-01‘, periods = 10, freq = ‘3D‘)#不传freq则默认是D rng
结果:
DatetimeIndex([‘2016-07-01‘, ‘2016-07-04‘, ‘2016-07-07‘, ‘2016-07-10‘, ‘2016-07-13‘, ‘2016-07-16‘, ‘2016-07-19‘, ‘2016-07-22‘, ‘2016-07-25‘, ‘2016-07-28‘], dtype=‘datetime64[ns]‘, freq=‘3D‘)
time=pd.Series(np.random.randn(20), index=pd.date_range(dt.datetime(2016,1,1),periods=20)) print(time) #结果: 2016-01-01 -0.129379 2016-01-02 0.164480 2016-01-03 -0.639117 2016-01-04 -0.427224 2016-01-05 2.055133 2016-01-06 1.116075 2016-01-07 0.357426 2016-01-08 0.274249 2016-01-09 0.834405 2016-01-10 -0.005444 2016-01-11 -0.134409 2016-01-12 0.249318 2016-01-13 -0.297842 2016-01-14 -0.128514 2016-01-15 0.063690 2016-01-16 -2.246031 2016-01-17 0.359552 2016-01-18 0.383030 2016-01-19 0.402717 2016-01-20 -0.694068 Freq: D, dtype: float64
truncate过滤
time.truncate(before=‘2016-1-10‘)#1月10之前的都被过滤掉了
结果:
2016-01-10 -0.005444 2016-01-11 -0.134409 2016-01-12 0.249318 2016-01-13 -0.297842 2016-01-14 -0.128514 2016-01-15 0.063690 2016-01-16 -2.246031 2016-01-17 0.359552 2016-01-18 0.383030 2016-01-19 0.402717 2016-01-20 -0.694068 Freq: D, dtype: float64
time.truncate(after=‘2016-1-10‘)#1月10之后的都被过滤掉了 #结果: 2016-01-01 -0.129379 2016-01-02 0.164480 2016-01-03 -0.639117 2016-01-04 -0.427224 2016-01-05 2.055133 2016-01-06 1.116075 2016-01-07 0.357426 2016-01-08 0.274249 2016-01-09 0.834405 2016-01-10 -0.005444 Freq: D, dtype: float64
print(time[‘2016-01-15‘])#0.063690487247 print(time[‘2016-01-15‘:‘2016-01-20‘]) 结果: 2016-01-15 0.063690 2016-01-16 -2.246031 2016-01-17 0.359552 2016-01-18 0.383030 2016-01-19 0.402717 2016-01-20 -0.694068 Freq: D, dtype: float64 data=pd.date_range(‘2010-01-01‘,‘2011-01-01‘,freq=‘M‘) print(data) #结果: DatetimeIndex([‘2010-01-31‘, ‘2010-02-28‘, ‘2010-03-31‘, ‘2010-04-30‘, ‘2010-05-31‘, ‘2010-06-30‘, ‘2010-07-31‘, ‘2010-08-31‘, ‘2010-09-30‘, ‘2010-10-31‘, ‘2010-11-30‘, ‘2010-12-31‘], dtype=‘datetime64[ns]‘, freq=‘M‘)
#时间戳 pd.Timestamp(‘2016-07-10‘)#Timestamp(‘2016-07-10 00:00:00‘) # 可以指定更多细节 pd.Timestamp(‘2016-07-10 10‘)#Timestamp(‘2016-07-10 10:00:00‘) pd.Timestamp(‘2016-07-10 10:15‘)#Timestamp(‘2016-07-10 10:15:00‘) # How much detail can you add? t = pd.Timestamp(‘2016-07-10 10:15‘) # 时间区间 pd.Period(‘2016-01‘)#Period(‘2016-01‘, ‘M‘) pd.Period(‘2016-01-01‘)#Period(‘2016-01-01‘, ‘D‘) # TIME OFFSETS pd.Timedelta(‘1 day‘)#Timedelta(‘1 days 00:00:00‘) pd.Period(‘2016-01-01 10:10‘) + pd.Timedelta(‘1 day‘)#Period(‘2016-01-02 10:10‘, ‘T‘) pd.Timestamp(‘2016-01-01 10:10‘) + pd.Timedelta(‘1 day‘)#Timestamp(‘2016-01-02 10:10:00‘) pd.Timestamp(‘2016-01-01 10:10‘) + pd.Timedelta(‘15 ns‘)#Timestamp(‘2016-01-01 10:10:00.000000015‘) p1 = pd.period_range(‘2016-01-01 10:10‘, freq = ‘25H‘, periods = 10) p2 = pd.period_range(‘2016-01-01 10:10‘, freq = ‘1D1H‘, periods = 10) p1 p2 结果: PeriodIndex([‘2016-01-01 10:00‘, ‘2016-01-02 11:00‘, ‘2016-01-03 12:00‘, ‘2016-01-04 13:00‘, ‘2016-01-05 14:00‘, ‘2016-01-06 15:00‘, ‘2016-01-07 16:00‘, ‘2016-01-08 17:00‘, ‘2016-01-09 18:00‘, ‘2016-01-10 19:00‘], dtype=‘period[25H]‘, freq=‘25H‘) PeriodIndex([‘2016-01-01 10:00‘, ‘2016-01-02 11:00‘, ‘2016-01-03 12:00‘, ‘2016-01-04 13:00‘, ‘2016-01-05 14:00‘, ‘2016-01-06 15:00‘, ‘2016-01-07 16:00‘, ‘2016-01-08 17:00‘, ‘2016-01-09 18:00‘, ‘2016-01-10 19:00‘], dtype=‘period[25H]‘, freq=‘25H‘) # 指定索引 rng = pd.date_range(‘2016 Jul 1‘, periods = 10, freq = ‘D‘) rng pd.Series(range(len(rng)), index = rng) 结果: 2016-07-01 0 2016-07-02 1 2016-07-03 2 2016-07-04 3 2016-07-05 4 2016-07-06 5 2016-07-07 6 2016-07-08 7 2016-07-09 8 2016-07-10 9 Freq: D, dtype: int32 periods = [pd.Period(‘2016-01‘), pd.Period(‘2016-02‘), pd.Period(‘2016-03‘)] ts = pd.Series(np.random.randn(len(periods)), index = periods) ts 结果: 2016-01 -0.015837 2016-02 -0.923463 2016-03 -0.485212 Freq: M, dtype: float64 type(ts.index)#pandas.core.indexes.period.PeriodIndex # 时间戳和时间周期可以转换 ts = pd.Series(range(10), pd.date_range(‘07-10-16 8:00‘, periods = 10, freq = ‘H‘)) ts 结果: 2016-07-10 08:00:00 0 2016-07-10 09:00:00 1 2016-07-10 10:00:00 2 2016-07-10 11:00:00 3 2016-07-10 12:00:00 4 2016-07-10 13:00:00 5 2016-07-10 14:00:00 6 2016-07-10 15:00:00 7 2016-07-10 16:00:00 8 2016-07-10 17:00:00 9 Freq: H, dtype: int32 ts_period = ts.to_period() ts_period 结果: 2016-07-10 08:00 0 2016-07-10 09:00 1 2016-07-10 10:00 2 2016-07-10 11:00 3 2016-07-10 12:00 4 2016-07-10 13:00 5 2016-07-10 14:00 6 2016-07-10 15:00 7 2016-07-10 16:00 8 2016-07-10 17:00 9 Freq: H, dtype: int32 时间周期与时间戳的区别 ts_period[‘2016-07-10 08:30‘:‘2016-07-10 11:45‘] #时间周期包含08:00 结果: 2016-07-10 08:00 0 2016-07-10 09:00 1 2016-07-10 10:00 2 2016-07-10 11:00 3 Freq: H, dtype: int32 ts[‘2016-07-10 08:30‘:‘2016-07-10 11:45‘] #时间戳不包含08:30 #结果: 2016-07-10 09:00:00 1 2016-07-10 10:00:00 2 2016-07-10 11:00:00 3 Freq: H, dtype: int32
数据重采样:
- 时间数据由一个频率转换到另一个频率
- 降采样
- 升采样
import pandas as pd import numpy as np rng = pd.date_range(‘1/1/2011‘, periods=90, freq=‘D‘)#数据按天 ts = pd.Series(np.random.randn(len(rng)), index=rng) ts.head() 结果: 2011-01-01 -1.025562 2011-01-02 0.410895 2011-01-03 0.660311 2011-01-04 0.710293 2011-01-05 0.444985 Freq: D, dtype: float64 ts.resample(‘M‘).sum()#数据降采样,降为月,指标是求和,也可以平均,自己指定 结果: 2011-01-31 2.510102 2011-02-28 0.583209 2011-03-31 2.749411 Freq: M, dtype: float64 ts.resample(‘3D‘).sum()#数据降采样,降为3天 结果: 2011-01-01 0.045643 2011-01-04 -2.255206 2011-01-07 0.571142 2011-01-10 0.835032 2011-01-13 -0.396766 2011-01-16 -1.156253 2011-01-19 -1.286884 2011-01-22 2.883952 2011-01-25 1.566908 2011-01-28 1.435563 2011-01-31 0.311565 2011-02-03 -2.541235 2011-02-06 0.317075 2011-02-09 1.598877 2011-02-12 -1.950509 2011-02-15 2.928312 2011-02-18 -0.733715 2011-02-21 1.674817 2011-02-24 -2.078872 2011-02-27 2.172320 2011-03-02 -2.022104 2011-03-05 -0.070356 2011-03-08 1.276671 2011-03-11 -2.835132 2011-03-14 -1.384113 2011-03-17 1.517565 2011-03-20 -0.550406 2011-03-23 0.773430 2011-03-26 2.244319 2011-03-29 2.951082 Freq: 3D, dtype: float64 day3Ts = ts.resample(‘3D‘).mean() day3Ts 结果: 2011-01-01 0.015214 2011-01-04 -0.751735 2011-01-07 0.190381 2011-01-10 0.278344 2011-01-13 -0.132255 2011-01-16 -0.385418 2011-01-19 -0.428961 2011-01-22 0.961317 2011-01-25 0.522303 2011-01-28 0.478521 2011-01-31 0.103855 2011-02-03 -0.847078 2011-02-06 0.105692 2011-02-09 0.532959 2011-02-12 -0.650170 2011-02-15 0.976104 2011-02-18 -0.244572 2011-02-21 0.558272 2011-02-24 -0.692957 2011-02-27 0.724107 2011-03-02 -0.674035 2011-03-05 -0.023452 2011-03-08 0.425557 2011-03-11 -0.945044 2011-03-14 -0.461371 2011-03-17 0.505855 2011-03-20 -0.183469 2011-03-23 0.257810 2011-03-26 0.748106 2011-03-29 0.983694 Freq: 3D, dtype: float64 print(day3Ts.resample(‘D‘).asfreq())#升采样,要进行插值 结果: 2011-01-01 0.015214 2011-01-02 NaN 2011-01-03 NaN 2011-01-04 -0.751735 2011-01-05 NaN 2011-01-06 NaN 2011-01-07 0.190381 2011-01-08 NaN 2011-01-09 NaN 2011-01-10 0.278344 2011-01-11 NaN 2011-01-12 NaN 2011-01-13 -0.132255 2011-01-14 NaN 2011-01-15 NaN 2011-01-16 -0.385418 2011-01-17 NaN 2011-01-18 NaN 2011-01-19 -0.428961 2011-01-20 NaN 2011-01-21 NaN 2011-01-22 0.961317 2011-01-23 NaN 2011-01-24 NaN 2011-01-25 0.522303 2011-01-26 NaN 2011-01-27 NaN 2011-01-28 0.478521 2011-01-29 NaN 2011-01-30 NaN ... 2011-02-28 NaN 2011-03-01 NaN 2011-03-02 -0.674035 2011-03-03 NaN 2011-03-04 NaN 2011-03-05 -0.023452 2011-03-06 NaN 2011-03-07 NaN 2011-03-08 0.425557 2011-03-09 NaN 2011-03-10 NaN 2011-03-11 -0.945044 2011-03-12 NaN 2011-03-13 NaN 2011-03-14 -0.461371 2011-03-15 NaN 2011-03-16 NaN 2011-03-17 0.505855 2011-03-18 NaN 2011-03-19 NaN 2011-03-20 -0.183469 2011-03-21 NaN 2011-03-22 NaN 2011-03-23 0.257810 2011-03-24 NaN 2011-03-25 NaN 2011-03-26 0.748106 2011-03-27 NaN 2011-03-28 NaN 2011-03-29 0.983694 Freq: D, Length: 88, dtype: float64
插值方法:
- ffill 空值取前面的值
- bfill 空值取后面的值
- interpolate 线性取值
day3Ts.resample(‘D‘).ffill(1) 结果: 2011-01-01 0.015214 2011-01-02 0.015214 2011-01-03 NaN 2011-01-04 -0.751735 2011-01-05 -0.751735 2011-01-06 NaN 2011-01-07 0.190381 2011-01-08 0.190381 2011-01-09 NaN 2011-01-10 0.278344 2011-01-11 0.278344 2011-01-12 NaN 2011-01-13 -0.132255 2011-01-14 -0.132255 2011-01-15 NaN 2011-01-16 -0.385418 2011-01-17 -0.385418 2011-01-18 NaN 2011-01-19 -0.428961 2011-01-20 -0.428961 2011-01-21 NaN 2011-01-22 0.961317 2011-01-23 0.961317 2011-01-24 NaN 2011-01-25 0.522303 2011-01-26 0.522303 2011-01-27 NaN 2011-01-28 0.478521 2011-01-29 0.478521 2011-01-30 NaN ... 2011-02-28 0.724107 2011-03-01 NaN 2011-03-02 -0.674035 2011-03-03 -0.674035 2011-03-04 NaN 2011-03-05 -0.023452 2011-03-06 -0.023452 2011-03-07 NaN 2011-03-08 0.425557 2011-03-09 0.425557 2011-03-10 NaN 2011-03-11 -0.945044 2011-03-12 -0.945044 2011-03-13 NaN 2011-03-14 -0.461371 2011-03-15 -0.461371 2011-03-16 NaN 2011-03-17 0.505855 2011-03-18 0.505855 2011-03-19 NaN 2011-03-20 -0.183469 2011-03-21 -0.183469 2011-03-22 NaN 2011-03-23 0.257810 2011-03-24 0.257810 2011-03-25 NaN 2011-03-26 0.748106 2011-03-27 0.748106 2011-03-28 NaN 2011-03-29 0.983694 Freq: D, Length: 88, dtype: float64 day3Ts.resample(‘D‘).bfill(1) 结果: 2011-01-01 0.015214 2011-01-02 NaN 2011-01-03 -0.751735 2011-01-04 -0.751735 2011-01-05 NaN 2011-01-06 0.190381 2011-01-07 0.190381 2011-01-08 NaN 2011-01-09 0.278344 2011-01-10 0.278344 2011-01-11 NaN 2011-01-12 -0.132255 2011-01-13 -0.132255 2011-01-14 NaN 2011-01-15 -0.385418 2011-01-16 -0.385418 2011-01-17 NaN 2011-01-18 -0.428961 2011-01-19 -0.428961 2011-01-20 NaN 2011-01-21 0.961317 2011-01-22 0.961317 2011-01-23 NaN 2011-01-24 0.522303 2011-01-25 0.522303 2011-01-26 NaN 2011-01-27 0.478521 2011-01-28 0.478521 2011-01-29 NaN 2011-01-30 0.103855 ... 2011-02-28 NaN 2011-03-01 -0.674035 2011-03-02 -0.674035 2011-03-03 NaN 2011-03-04 -0.023452 2011-03-05 -0.023452 2011-03-06 NaN 2011-03-07 0.425557 2011-03-08 0.425557 2011-03-09 NaN 2011-03-10 -0.945044 2011-03-11 -0.945044 2011-03-12 NaN 2011-03-13 -0.461371 2011-03-14 -0.461371 2011-03-15 NaN 2011-03-16 0.505855 2011-03-17 0.505855 2011-03-18 NaN 2011-03-19 -0.183469 2011-03-20 -0.183469 2011-03-21 NaN 2011-03-22 0.257810 2011-03-23 0.257810 2011-03-24 NaN 2011-03-25 0.748106 2011-03-26 0.748106 2011-03-27 NaN 2011-03-28 0.983694 2011-03-29 0.983694 Freq: D, Length: 88, dtype: float64 day3Ts.resample(‘D‘).interpolate(‘linear‘)#线性拟合填充 结果: 2011-01-01 0.015214 2011-01-02 -0.240435 2011-01-03 -0.496085 2011-01-04 -0.751735 2011-01-05 -0.437697 2011-01-06 -0.123658 2011-01-07 0.190381 2011-01-08 0.219702 2011-01-09 0.249023 2011-01-10 0.278344 2011-01-11 0.141478 2011-01-12 0.004611 2011-01-13 -0.132255 2011-01-14 -0.216643 2011-01-15 -0.301030 2011-01-16 -0.385418 2011-01-17 -0.399932 2011-01-18 -0.414447 2011-01-19 -0.428961 2011-01-20 0.034465 2011-01-21 0.497891 2011-01-22 0.961317 2011-01-23 0.814979 2011-01-24 0.668641 2011-01-25 0.522303 2011-01-26 0.507709 2011-01-27 0.493115 2011-01-28 0.478521 2011-01-29 0.353632 2011-01-30 0.228744 ... 2011-02-28 0.258060 2011-03-01 -0.207988 2011-03-02 -0.674035 2011-03-03 -0.457174 2011-03-04 -0.240313 2011-03-05 -0.023452 2011-03-06 0.126218 2011-03-07 0.275887 2011-03-08 0.425557 2011-03-09 -0.031310 2011-03-10 -0.488177 2011-03-11 -0.945044 2011-03-12 -0.783820 2011-03-13 -0.622595 2011-03-14 -0.461371 2011-03-15 -0.138962 2011-03-16 0.183446 2011-03-17 0.505855 2011-03-18 0.276080 2011-03-19 0.046306 2011-03-20 -0.183469 2011-03-21 -0.036376 2011-03-22 0.110717 2011-03-23 0.257810 2011-03-24 0.421242 2011-03-25 0.584674 2011-03-26 0.748106 2011-03-27 0.826636 2011-03-28 0.905165 2011-03-29 0.983694 Freq: D, Length: 88, dtype: float64
Pandas滑动窗口:
滑动窗口就是能够根据指定的单位长度来框住时间序列,从而计算框内的统计指标。相当于一个长度指定的滑块在刻度尺上面滑动,每滑动一个单位即可反馈滑块内的数据。
滑动窗口可以使数据更加平稳,浮动范围会比较小,具有代表性,单独拿出一个数据可能或多或少会离群,有差异或者错误,使用滑动窗口会更规范一些。
%matplotlib inline import matplotlib.pylab import numpy as np import pandas as pd df = pd.Series(np.random.randn(600), index = pd.date_range(‘7/1/2016‘, freq = ‘D‘, periods = 600)) df.head() 结果: 2016-07-01 -0.192140 2016-07-02 0.357953 2016-07-03 -0.201847 2016-07-04 -0.372230 2016-07-05 1.414753 Freq: D, dtype: float64 r = df.rolling(window = 10) r#Rolling [window=10,center=False,axis=0] #r.max, r.median, r.std, r.skew倾斜度, r.sum, r.var print(r.mean()) 结果: 2016-07-01 NaN 2016-07-02 NaN 2016-07-03 NaN 2016-07-04 NaN 2016-07-05 NaN 2016-07-06 NaN 2016-07-07 NaN 2016-07-08 NaN 2016-07-09 NaN 2016-07-10 0.300133 2016-07-11 0.284780 2016-07-12 0.252831 2016-07-13 0.220699 2016-07-14 0.167137 2016-07-15 0.018593 2016-07-16 -0.061414 2016-07-17 -0.134593 2016-07-18 -0.153333 2016-07-19 -0.218928 2016-07-20 -0.169426 2016-07-21 -0.219747 2016-07-22 -0.181266 2016-07-23 -0.173674 2016-07-24 -0.130629 2016-07-25 -0.166730 2016-07-26 -0.233044 2016-07-27 -0.256642 2016-07-28 -0.280738 2016-07-29 -0.289893 2016-07-30 -0.379625 ... 2018-01-22 -0.211467 2018-01-23 0.034996 2018-01-24 -0.105910 2018-01-25 -0.145774 2018-01-26 -0.089320 2018-01-27 -0.164370 2018-01-28 -0.110892 2018-01-29 -0.205786 2018-01-30 -0.101162 2018-01-31 -0.034760 2018-02-01 0.229333 2018-02-02 0.043741 2018-02-03 0.052837 2018-02-04 0.057746 2018-02-05 -0.071401 2018-02-06 -0.011153 2018-02-07 -0.045737 2018-02-08 -0.021983 2018-02-09 -0.196715 2018-02-10 -0.063721 2018-02-11 -0.289452 2018-02-12 -0.050946 2018-02-13 -0.047014 2018-02-14 0.048754 2018-02-15 0.143949 2018-02-16 0.424823 2018-02-17 0.361878 2018-02-18 0.363235 2018-02-19 0.517436 2018-02-20 0.368020 Freq: D, Length: 600, dtype: float64 import matplotlib.pyplot as plt %matplotlib inline plt.figure(figsize=(15, 5)) df.plot(style=‘r--‘) df.rolling(window=10).mean().plot(style=‘b‘)#<matplotlib.axes._subplots.AxesSubplot at 0x249627fb6d8>
结果:
数据平稳性与差分法:
二阶差分是指在一阶差分基础上再做一阶差分。
相关函数评估方法:
原文地址:https://www.cnblogs.com/tianqizhi/p/9277376.html
时间: 2024-11-04 23:50:39