Question

我试图计算两个向量之间的夹角，其中两个向量都在同一数据帧中，但是每个数据帧在一个列表中。这是我尝试过的MRE。

rm(list=ls())

coords <- rnorm(10)
x.h <- rnorm(10)
y.h <- rnorm(10)
liklihood.h <- rnorm(10)
x.MB <- rnorm(10)
y.MB <- rnorm(10)
x.a <- rnorm(10)
y.a <- rnorm(10)

day1 <-  data.frame(coords,x.h,y.h,liklihood.h,x.MB,y.MB,x.a,y.a)

coords <- rnorm(10)
x.h <- rnorm(10)
y.h <- rnorm(10)
liklihoo.d.h <- rnorm(10)
x.MB <- rnorm(10)
y.MB <- rnorm(10)
x.a <- rnorm(10)
y.a <- rnorm(10)

day2 <-  data.frame(coords,x.h,y.h,liklihood.h,x.MB,y.MB,x.a,y.a)

data <- list(day1,day2)

angle <- function(x,y){
  dot.prod <- x%*%y
  norm.x <- norm(x,type="2")
  norm.y <- norm(y,type="2")
  theta <- acos(dot.prod / (norm.x * norm.y))
  as.numeric(theta)

}

append_angles <- function(df1){ 
  vect1 = c((df1$x.h-df1$x.MB),(df1$y.h-df1$y.MB))
  vect2 = c((df1$x.a-df1$x.MB),(df1$y.a-df1$y.MB))
  df1$theta = (angle(vect1, vect2)*(180/pi)) 
  return(df1)
}

data <-  mapply(append_angles, data, SIMPLIFY = FALSE)

我最终从针对每个数据帧重复的计算中而不是针对每一行的计算中获得第一个值。我如何使它计算出每一行的值？

Answer 1

基于创建的函数，我们可以split逐行然后应用

out <- Map(function(x) do.call(rbind, lapply(split(x, seq_len(nrow(x))),
         append_angles)), data)
out
#[[1]]
#         coords        x.h         y.h liklihood.h        x.MB       y.MB        x.a         y.a      theta
#1  -0.545880758 -1.3169081 -0.07430856 -0.03373792  0.06735770  0.5266526  1.4520752  0.14379993 141.077262
#2   0.536585304  0.5982691 -0.60515695 -0.58542756  0.01710596 -1.0736261  0.4082015 -0.88610999  13.255879
#3   0.419623149 -0.7622144 -1.70964518  0.61285136 -0.34365937  0.7696819 -0.4403340 -0.02557419   2.651103
#4  -0.583627199 -1.4290903 -0.26869311  1.51712249 -0.66789220  1.7709054  1.3185662 -0.32773539  63.893042
#5   0.847460017  0.3322444 -0.64859151  0.65738044 -0.25574457 -0.1961822  0.5713866 -0.07596102  45.845198
#6   0.266021979 -0.4690607 -0.09411013 -1.07418134 -0.46120796  0.2047497 -1.2799872 -1.35466363  26.196849
#7   0.444585270 -0.3349868 -0.08554095 -4.46956441  1.47164158 -0.5965981 -1.2388796 -0.96080882  23.448044
#8  -0.466495124  1.5362522  0.11953107  0.36904502 -0.09196032  1.1782477 -0.9225911  0.22495434  98.033303
#9  -0.848370044  0.6099945 -0.11629639  0.16922669  0.33519430  1.0494212  1.3496121 -0.12316046  27.599124
#10  0.002311942  0.5163357 -0.94382724 -1.82219032 -0.23186459  0.5609812 -1.5676166  0.00104102  93.693684

#[[2]]
#         coords        x.h         y.h liklihood.h        x.MB        y.MB          x.a         y.a      theta
#1  -0.571243248 -0.2327672  0.08314367 -0.03373792  1.01283626 -2.46745604  0.667163872 -0.07045269  17.822834
#2   0.422621775 -1.4203631  2.78494703 -0.58542756  0.02534344 -0.05040743 -0.008576239 -0.75031916 150.209075
#3  -1.673385810 -0.8133227  0.59528232  0.61285136 -0.50715002  0.24643818  0.092440453 -0.09401376 160.860935
#4  -1.136025931  0.4610693  0.07766635  1.51712249 -0.50694324  1.53136287  0.320282642  0.41274946   2.823761
#5   0.361212489 -0.2148936 -0.55869661  0.65738044  0.26498877  0.59163787  0.165091251 -1.25747896  19.551954
#6   1.056864213  0.1389452 -0.80676768 -1.07418134  0.59168174 -1.61854195 -1.053206734  0.19706349  13.026765
#7  -1.992920453  0.8442304 -0.51070906 -4.46956441 -0.28834071 -0.63493218  0.447394677 -1.89231492  65.926033
#8   0.764385054 -1.3084503 -0.55648712  0.36904502 -0.52907038  1.35675449  1.057136825  0.25217616  77.312082
#9   0.007165349  1.0451687  0.24112516  0.16922669 -0.17986538 -0.75802712 -1.475157330 -0.64785092 135.937090
#10  0.101974336  1.2101739 -0.57533702 -1.82219032 -0.93043770  0.37536404  0.200732860 -0.26605768   5.607831

如何将功能映射到列表中每个数据框的每一行？

1 个答案: