如何计算数据帧的所有行与r中的最后一行之间的欧几里得距离

Question

I have a data frame and would like to calculate the Euclidean distance between all rows and the last row and add the distance value as a new column to data frame using distance function.

Do you have any idea how can I do this.

here is an example of data frame:

df = data.frame(
      x = rnorm(10),
      y = rnorm(10),
      z = rnorm(10)
 )

This is the desired output

        x          y           z     dist
1   2.4720136 -2.5332449 -0.29877255 1.956157
2   0.2616905 -0.5988683 -0.68586911 3.434874
3   0.4706199 -0.7911288 -0.07673025 2.700038
4   0.7202775 -2.0615370 -0.93959256 2.493054
5  -0.3002038  1.5872991  1.43678171 2.310108
6  -2.1274192  1.9746993  0.55372197 4.39925
7   0.2568586  0.2206467  0.22742260 3.482363
8   1.3476458 -0.2029571 -0.98492886 1.459337
9  -1.1968263 -0.4381387  0.93461394 2.180699
10 -0.2995206 -1.6586264 -0.25067014 NA

Answer 1

You can use dist to find the distances between each row of the dataframe, eg:

df = data.frame(
    x = rnorm(10),
    y = rnorm(10),
    z = rnorm(10)
)

# This will generate all the pairwise differences
#   Might be an issue of very large datasets
#   where speed will be an issue
df$dist = as.matrix(dist(df))[nrow(df), ]