Question

我有一个包含时间数据的数据框，我希望将某些行标记为属于感兴趣的时段。例如：

time <- c(1,2,3,5,7,9,23,24,28,43,45)
action <- c("clap","blink","stare","stare","clap","stare",
"clap","blink","stare","clap","stare")

我想找到每个拍手中5秒内发生的事情，希望通过创建一个新列，每个新的拍手和拍后拍摄序列都有一个索引标记。

我是R的新手所以可能有一种方法可以帮助我找到答案，所以如果是这样的话我会道歉。

Answer 1

我相信这可以做你想要的。请注意，我已经在data.frame添加了一行，因为你提到你需要一个标识符来查看在拍手后5秒内是否发生了某些事情。

# Your data
time <- c(1,2,3,5,7,9,23,24,28,43,45)
action <- c("clap","blink","stare","stare","clap","stare",
            "clap","blink","stare","clap","stare")
df = data.frame(time=time,action=action)

# Added a row that does not occur within 5 seconds of a clap for illustration purposes.
df = rbind(df,data.frame(time=100,action='stare'))

# Add the group number, based on the claps.
df = df %>% mutate(group=cumsum(action=='clap'))

# Check if action is within 5 seconds of a clap.
df = df %>% 
  group_by(group) %>% 
  mutate(within_5_seconds = ifelse(time-time[1]<=5,1,0)) %>%
  as.data.table

输出：

    time action group within_5_seconds
 1:    1   clap     1                1
 2:    2  blink     1                1
 3:    3  stare     1                1
 4:    5  stare     1                1
 5:    7   clap     2                1
 6:    9  stare     2                1
 7:   23   clap     3                1
 8:   24  blink     3                1
 9:   28  stare     3                1
10:   43   clap     4                1
11:   45  stare     4                1
12:  100  stare     4                0

在数据框中标记给定值的所有值

1 个答案: