有没有办法只生成随机的“时间”？

lubridate是目前最友好的包处理时间。只需生成您需要的间隔并从中采样：

library(lubridate)

> sample(as.duration(0:599), 30)
[1] "345s (~5.75 minutes)" "277s (~4.62 minutes)" "74s (~1.23 minutes)" 
[4] "15s"                  "571s (~9.52 minutes)" "186s (~3.1 minutes)" 
[7] "45s"                  "355s (~5.92 minutes)" "121s (~2.02 minutes)"
[10] "488s (~8.13 minutes)" "179s (~2.98 minutes)" "371s (~6.18 minutes)"
[13] "515s (~8.58 minutes)" "31s"                  "346s (~5.77 minutes)"
[16] "0s"                   "398s (~6.63 minutes)" "84s (~1.4 minutes)"  
[19] "160s (~2.67 minutes)" "457s (~7.62 minutes)" "94s (~1.57 minutes)" 
[22] "212s (~3.53 minutes)" "591s (~9.85 minutes)" "576s (~9.6 minutes)" 
[25] "348s (~5.8 minutes)"  "314s (~5.23 minutes)" "563s (~9.38 minutes)"
[28] "509s (~8.48 minutes)" "538s (~8.97 minutes)" "71s (~1.18 minutes)" 

检查函数 interval() 和 ms() 以获得其他可能的方法来获得你想要的东西。

但是正如评论中指出的那样，如果您需要的只是以秒为单位的随机间隔，那么使用整数会更简单、更方便。