Calculate euclidean distance

I have data where rows are points and columns are coordinates x,y,z.

I'd like to calculate euclidean distance between points in couple, as 3-4, 11-12, 18-19 and so on... for example, I dont' need distance between 3 and 11, 12, 18 The problem is that I have to analize 1074 tables with 1000 rows or more, so I'm searching a way to do it automatically, maybe considering tha fact that I want to calculate distance between an odd number and the even following one. I don't care too much about the output format, but pls consider that after I have to select only distances <3.2, so a dataframe format will be great.

How about something like this:

First, I'll make some fake data

set.seed(4304)
df <- data.frame(
  x = runif(1000, -1, 1), 
  y = runif(1000, -1, 1), 
  z = runif(1000, -1,1)
)

Make a sequence of values from 1 to the number of rows of your dataset by 2s.

s <- seq(1, nrow(df), by=2)

Use sapply() to make the distance between each pair of points.

out <- sapply(s, function(i){
  sqrt(sum((df[i,] - df[(i+1), ])^2))
})

Organize the distances into a data frame

res <- data.frame(
  pair = paste(rownames(df)[s], rownames(df)[(s+1)], sep="-"), 
  dist=out)
head(res)
#     pair     dist
# 1   1-2 1.379992
# 2   3-4 1.303511
# 3   5-6 1.242302
# 4   7-8 1.257228
# 5  9-10 1.107484
# 6 11-12 1.392247