如何在R中生成一个正负分数序列

Question

I would like to generate sequences of positives and negatives numbers in a specific interval. For example, I would like to generate 10 numbers in [0.2,-0.9] without zeros . Here are my tries:

x <- sample(0.5:-0.9, 20, replace=T)
x
 [1]  0.5  0.5 -0.5  0.5  0.5 -0.5  0.5  0.5 -0.5 -0.5  0.5  0.5  0.5 -0.5  0.5
[16] -0.5  0.5  0.5  0.5 -0.5
x <- sample(0.2:-0.9, 20, replace=T)
x
 [1]  0.2 -0.8  0.2 -0.8 -0.8 -0.8 -0.8 -0.8 -0.8  0.2 -0.8 -0.8 -0.8  0.2 -0.8
[16] -0.8 -0.8 -0.8 -0.8 -0.8
 x <- seq(0.2, -0.9)
 x
[1]  0.2 -0.8

All my tries did not give me what I want. The expected output is, for example,

0.2, -0.25, 0.3, 0.4, -0.5, 0.5, -0.9, -0.6, 0.7, 0.6

Any help, please?

Answer 1

The answer below adds the new requirement at the end (about not having 0).

You need seq and to have the numbers in the correct order:

sample(seq(0.2,from=-0.9,by=.1), 10, replace=T)

 [1] -0.1 -0.6 0.2 0.0 0.0 0.1 0.2 -0.8 -0.7 -0.2 

and I recommend sample_n :

library(dplyr)
sample_n(as_tibble(seq(0.2,from=-0.9,by=.1)), 10, replace=T)

  value <dbl> 1 0.100 2 -0.200 3 0. 4 -0.100 5 0. 6 -0.100 7 -0.600 8 -0.800 9 -0.900 10 -0.900 

Update:

You mentioned you don't want 0. There are many ways to accomplish this. The best way probably depends on the set of statistical implications that you prefer if that's important to you. Here are some examples:

Example 1

x <- sample(seq(0.2,from=-0.9,by=.1), 10, replace=T)

ifelse(x==0, sample(seq(-.1,from=-0.9,by=.1), 1, replace=T), x)

Example 2

c(sample(seq(-.1,from=-0.9,by=.1), 5, replace=T),
  sample(seq(.1, 0.2,by=.1), 5, replace=T))

You could also use a while . Basically for each element you'd take random samples until there's one that's not == 0 . That's probably how I would do it to avoid polluting the distributional assumptions.