用R计算事件的持续时间

Question

我正在研究传感器数据库

这是我的数据的子集

我想计算所有传感器的每个'ON'事件的持续时间。 知道'ON'的持续时间等于第一个ON和第一个OFF之间的差值 例如在传感器'capteur1'的表中，我必须有41秒，30秒，25秒等。 谢，

Answer 1

简短代码 - 尝试一下：

# important - time must be a time-element (strptime or use format for example)

# subset only ON and OFF
ON <- df$time[df$capteur1 %in% "ON"]
OFF <- df$time[df$capteur1 %in% "OFF"]

# Create tempoary element to append to in for-loop
temp <- NULL # temp stands for temporary
name_temp <- NULL

# Loop over ON-Elements
for (i in ON) {
    a <- difftime(OFF, i, units = "sec") # difftime of i-element of ON vs all OFF
    a <- a[!a < 0] # drop negative seconds as Off was before on
    # append positive Seconds - but only the first element - as this was the next OFF
    temp <- c(temp, a[1])
    name_temp <- c(name_temp, as.character(i))
    }

# Give names to elements
names(temp) <- name_temp

# show temp
temp

希望这有帮助

塞巴斯蒂安