有没有办法计算两个参数的标准差和平均值？

Question

我使用 groupby 生成了以下内容 pd.DataFrame:

                       Timestemp  Altitude [m]  Sequence ID  Horizontal Wind Speed [m/s]  ...  Radial Wind Speed [m/s]  CNR [dB]  U-Component of Wind Speed  V-Component of Wind Speed 
0    2019-07-29 00:00:40.901           100       617375                       7.2750  ...                   -0.006   -15.706                   7.241811                  -0.694118
1    2019-07-29 00:00:40.901           150       617375                       8.0700  ...                    0.252   -14.960                   8.068156                  -0.172526
2    2019-07-29 00:00:40.901           200       617375                       9.6750  ...                    0.572   -13.872                   9.672698                  -0.211059
3    2019-07-29 00:00:40.901           250       617375                       9.7975  ...                    0.424   -12.584                   9.786624                   0.461525
4    2019-07-29 00:00:40.901           300       617375                       9.0325  ...                    0.054   -10.998                   9.029804                  -0.220684
...                      ...           ...          ...                          ...  ...                      ...       ...                        ...                        ...
1612 2019-07-29 00:16:59.713          1500       617425                          NaN  ...                      NaN       NaN                        NaN                        NaN
1613 2019-07-29 00:16:59.713          1550       617425                          NaN  ...                      NaN       NaN                        NaN                        NaN
1614 2019-07-29 00:16:59.713          1600       617425                          NaN  ...                      NaN       NaN                        NaN                        NaN
1615 2019-07-29 00:16:59.713          1650       617425                          NaN  ...                      NaN       NaN                        NaN                        NaN
1616 2019-07-29 00:16:59.713          1700       617425                          NaN  ...                      NaN       NaN                        NaN                        NaN

但现在有点棘手。我想计算每个高度上每 5 分钟的平均值和标准差。所以海拔高度超过 5 分钟的 Timestemp。

我该如何解决？有人有想法吗？谢谢

Answer 1

首先您需要将您的时间列设置为索引。然后就可以用采样频率计算均值和标准差了

df = df.set_index(pd.DatetimeIndex(df['Timestemp']))

dfmean = df.groupby(pd.Grouper(freq='5T')).mean()  # 5min
dfstd = df.groupby(pd.Grouper(freq='5T')).std()

Answer 2

您可以使用 resample 按 5 分钟 bin 对数据帧进行分组。首先，您需要将时间戳变量作为索引，然后应用 resample 函数。 “T”代表分钟。您可以在此处找到所有代码列表：pandas resample documentation

df.set_index('Timestamp', inplace=True)
df.resample("5T").mean()
df.resample("5T").std()

编辑：如果您还想按“高度”分组。请记住，您仍然需要索引上的时间戳。

df.groupby([pd.Grouper(freq="5Min"), "Altitude"]).mean()

df.groupby([pd.Grouper(freq="5Min"), "Altitude"]).std()

有没有办法计算两个参数的标准差和平均值？

Is there a way to calculate std and mean over two parameters?

python

mean

pandas

pandas-groupby