我有下一个DataFrame:
data=pd.read_csv('anual.csv', parse_dates='Fecha', index_col=0) data DatetimeIndex: 290 entries, 2011-01-01 00:00:00 to 2011-12-31 00:00:00 Data columns (total 12 columns): HR 290 non-null values PreciAcu 290 non-null values RadSolar 290 non-null values T 290 non-null values Presion 290 non-null values Tmax 290 non-null values HRmax 290 non-null values Presionmax 290 non-null values RadSolarmax 290 non-null values Tmin 290 non-null values HRmin 290 non-null values Presionmin 290 non-null values dtypes: float64(4), int64(8)
哪里:
data['HR'] Fecha 2011-01-01 37 2011-02-01 70 2011-03-01 62 2011-04-01 69 2011-05-01 72 2011-06-01 71 2011-07-01 71 2011-08-01 70 2011-09-01 40 ... 2011-12-17 92 2011-12-18 78 2011-12-19 79 2011-12-20 76 2011-12-21 78 2011-12-22 80 2011-12-23 72 2011-12-24 70
此外,有些月份并不总是完整的.我的目标是从每日数据计算每个月的平均值.这是通过以下方式实现的:
monthly=data.resample('M', how='mean') HR PreciAcu RadSolar T Presion Tmax Fecha 2011-01-31 68.586207 3.744828 163.379310 17.496552 0 25.875862 2011-02-28 68.666667 1.966667 208.000000 18.854167 0 28.879167 2011-03-31 69.136364 3.495455 218.090909 20.986364 0 30.359091 2011-04-30 68.956522 1.913043 221.130435 22.165217 0 31.708696 2011-05-31 72.700000 0.550000 201.100000 18.900000 0 27.460000 2011-06-30 70.821429 6.050000 214.000000 23.032143 0 30.621429 2011-07-31 78.034483 5.810345 188.206897 21.503448 0 27.951724 2011-08-31 71.750000 1.028571 214.750000 22.439286 0 30.657143 2011-09-30 72.481481 0.185185 196.962963 21.714815 0 29.596296 2011-10-31 68.083333 1.770833 224.958333 18.683333 0 27.075000 2011-11-30 71.750000 0.812500 169.625000 18.925000 0 26.237500 2011-12-31 71.833333 0.160000 159.533333 17.260000 0 25.403333
我发现的第一个错误是在降水列中,因为所有观测结果在1月份都是0,而在这个特定月份获得的平均值为3.74.
当Excel中的平均值与上面的结果进行比较时,存在显着差异.例如,Febrero的HR平均值是
mean HR using pandas=68.66 mean HR using excel=67
我找到的另一个细节:
data['PreciAcu']['2011-01'].count() 29 and should be 31
难道我做错了什么?我该如何解决这个错误?
附件csv文件:
[链接] https://www.dropbox.com/s/p5hl137bqm82j41/anual.csv
您的日期列被误解,因为它是DD/MM/YYYY格式.设置dayfirst=True
改为:
>>> df = pd.read_csv('anual.csv', parse_dates='Fecha', dayfirst=True, index_col=0, sep="\s+") >>> df['PreciAcu']['2011-01'].count() 31 >>> df.resample("M").mean() HR PreciAcu RadSolar T Presion Tmax \ Fecha 2011-01-31 68.774194 0.000000 162.354839 16.535484 0 25.393548 2011-02-28 67.000000 0.000000 193.481481 15.418519 0 25.696296 2011-03-31 59.083333 0.850000 254.541667 21.295833 0 32.325000 2011-04-30 61.200000 1.312000 260.640000 24.676000 0 34.760000 2011-05-31 NaN NaN NaN NaN NaN NaN 2011-06-30 68.428571 8.576190 236.619048 25.009524 0 32.028571 2011-07-31 81.518519 11.488889 185.407407 22.429630 0 27.681481 2011-08-31 76.451613 0.677419 219.645161 23.677419 0 30.719355 2011-09-30 77.533333 2.883333 196.100000 21.573333 0 28.723333 2011-10-31 73.120000 1.260000 196.280000 19.552000 0 27.636000 2011-11-30 71.277778 -79.333333 148.555556 18.250000 0 26.511111 2011-12-31 73.741935 0.067742 134.677419 15.687097 0 24.019355 HRmax Presionmax Tmin Fecha 2011-01-31 92.709677 0 10.909677 2011-02-28 92.111111 0 8.325926 2011-03-31 89.291667 0 13.037500 2011-04-30 89.400000 0 17.328000 2011-05-31 NaN NaN NaN 2011-06-30 92.095238 0 19.761905 2011-07-31 97.185185 0 18.774074 2011-08-31 96.903226 0 18.670968 2011-09-30 97.200000 0 16.373333 2011-10-31 97.000000 0 13.412000 2011-11-30 94.555556 0 11.877778 2011-12-31 94.161290 0 10.070968 [12 rows x 9 columns]
(注意,虽然 - 我忘记了 - 这dayfirst=True
不严格,请看这里.也许使用date_parser
会更安全.)