合并多个数据框并计算平均值 [英] Combine multiple data frames and calculate average

问题描述

我有以下三个数据帧.我希望将它们组合成一个数据帧(根据Lon& amp;放置并平均每个单元格"的3个值.我已经阅读了此内容(计算多个数据帧的平均值)并尝试利用聚合，但无济于事....任何指针表示赞赏.

I have three data frames as below. I wish to combine them into one data frame according to Lon & Lat, and average the 3 values for each 'cell'. I have read this (calculate average over multiple data frames) and attempted to utilise aggregate but to no avail....any pointers appreciated.

> head(CSR.GRACE[,c(1:14)],10)
    Lon  Lat   January  February     March     April       May     June        July     August  September   October    November  December
1  28.5 -4.5 17.710425 13.855327 12.385712 13.558101 12.789865 6.913783  1.03770075 -5.3901741 -6.6351015 -7.661375 -3.09337944 6.0659410
2  29.5 -4.5 14.010154 10.257435  9.009641 10.275778  9.598241 5.166972  0.73570247 -4.2733162 -5.0861417 -5.850192 -2.93521806 4.1240150
3  30.5 -4.5 16.288443 10.467614  9.275714 10.904162 10.228808 5.364853  0.50089883 -4.7478741 -5.4320069 -6.316568 -3.80160315 3.8494745
4  31.5 -4.5 18.560677  9.932461  9.239592 11.037748 10.551886 5.281853  0.01181973 -4.9034324 -5.3504391 -6.438050 -4.41695714 3.3432301
5  32.5 -4.5 10.171202  4.476512  4.509140  5.448872  5.338991 2.556262 -0.22646611 -2.3274204 -2.4376636 -3.103697 -2.27586145 1.3641930
6  33.5 -4.5 14.040068  5.349344  5.772618  7.158792  7.121341 3.407587 -0.30616689 -2.6800099 -2.7955420 -3.803622 -2.77898997 1.4021380

> head(GFZ.GRACE[,c(1:14)],10)
    Lon  Lat   January  February     March     April       May      June     July     August September   October   November  December
1  28.5 -4.5 15.642782 15.521720 11.823875 19.825865 17.335761 11.208188 5.080615 -3.0897644 -5.733351 -4.196604 -1.6697661 10.744696
2  29.5 -4.5 12.164074 10.931418  8.622238 15.341911 12.969769  8.521280 4.072790 -2.4301791 -4.551170 -3.055914 -1.2260079  7.592880
3  30.5 -4.5 13.579305 10.267520  8.787406 16.567715 13.745143  9.121496 4.497849 -2.6723491 -5.022949 -3.269881 -1.0691039  7.377143
4  31.5 -4.5 14.501465  8.600480  8.259757 16.981533 14.054429  9.318550 4.582672 -2.7917893 -5.249895 -3.636936 -0.5141342  6.770836
5  32.5 -4.5  7.311216  3.249596  3.513870  8.430777  6.941659  4.572560 2.203461 -1.4106516 -2.661226 -2.113089  0.2459282  3.049897
6  33.5 -4.5  9.121348  3.113245  3.584976 11.040761  8.732950  5.772059 2.811168 -1.8554437 -3.524447 -3.272863  1.2493973  3.750694

> head(JPL.GRACE[,c(1:14)],10)
    Lon  Lat   January  February     March     April       May     June     July     August  September    October   November   December
1  28.5 -4.5 19.559790 14.544438 12.035112 13.944141 11.931011 7.513007 3.095003 -3.6165702 -6.5945043 -7.2498567 -4.5402436  6.3935236
2  29.5 -4.5 15.740160 11.192191  8.549782 10.783359  9.401173 5.834498 2.267822 -2.6354346 -4.8939197 -5.5912996 -3.7295148  4.1461123
3  30.5 -4.5 18.984714 12.014807  8.510139 11.628697 10.635699 6.448064 2.260429 -2.6979695 -5.2102337 -6.2646164 -4.2713238  3.5089825
4  31.5 -4.5 22.794356 11.993054  8.162500 11.813746 11.747350 6.955983 2.164615 -2.5707902 -5.3448873 -6.7473006 -4.5777496  2.5609555
5  32.5 -4.5 13.233634  5.606305  3.880347  5.753024  6.388978 3.742596 1.096214 -1.1103189 -2.6367831 -3.4102675 -2.2860237  0.7826054
6  33.5 -4.5 19.260989  6.761722  4.978247  7.373498  9.135645 5.421030 1.706414 -1.0796434 -3.3122886 -4.2114588 -2.8110246  0.4825075

推荐答案

您可以这样做:

library(data.table)

rbindlist(list(JPL.GRACE,GFZ.GRACE,CSR.GRACE))[,lapply(.SD,mean), list(Lon, Lat)]

说明:

将您的data.frames放入list中，并使用rbindlist返回水平"(返回data.table).我们这样做是因为您的data.frame具有相同的结构(相同的列号和名称，相同的数据类型). 另一种方法是进行do.call(rbind, list(JPL.GRACE,GFZ.GRACE,CSR.GRACE)).

Your data.frames are put into a list and 'superposed horizontaly' using rbindlist (which returns a data.table). We do this since your data.frame has the same structure (same number and name of columns, same type of data). An alternative approach would have been to do do.call(rbind, list(JPL.GRACE,GFZ.GRACE,CSR.GRACE)).

然后，我们遍历每对不同的Lon, Lat. .SD代表与每对关联的data.table.您可以这样做:

We then loop over each distinct pair of Lon, Lat. .SD represents the data.table associated with each pair. You can see it by doing:

dt = rbindlist(list(JPL.GRACE,GFZ.GRACE,CSR.GRACE))
dt[,print(.SD), list(Lon, Lat)]

对于每个.SD，我们只需在列上循环并计算均值即可.

For each of these .SD, we simply loop over the columns and compute the means.

这篇关于合并多个数据框并计算平均值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！