如何解决在新数据帧 R 中扩展时间序列
我是 R 新手，我收集了具有以下结构的眼动追踪数据：
Participant Trial Condition Fixation.Start Fixation.End Fixated.Area
P01 T01 Early 4 206 Outside
P01 T01 Early 258 476 Competitor
P01 T01 Early 496 882 Target
P01 T02 Late 4 794 Outside
P01 T02 Late 838 1026 Target
P01 T02 Late 1046 1328 Target
P02 T01 Early 4 168 Outside
P02 T01 Early 232 452 Competitor
P02 T01 Early 494 738 Target
P02 T02 Late 4 176 Outside
P02 T02 Late 238 466 Target
P02 T02 Late 524 632 Competitor
其中，屏幕上显示的不同区域的固定时间以毫秒为单位进行测量，从开始（Fixation Start）到结束（Fixation End）。每一行都是一个注视点。
我想做的是在新的数据帧中将数据重塑为 50 毫秒的时间段，以便每个时间段（行）反映当时正在注视的区域。换句话说，我希望新的数据框看起来像这样：
Participant Trial Condition Time.Bin Fixated.Area
P01 T01 Early 50 Outside
P01 T01 Early 100 Outside
P01 T01 Early 150 Outside
P01 T01 Early 200 Outside
P01 T01 Early 250 Competitor
P01 T01 Early 300 Competitor
P01 T01 Early 350 Competitor
P01 T01 Early 400 Competitor
P01 T01 Early 450 Competitor
P01 T01 Early 500 Target
P01 T01 Early 550 Target
P01 T01 Early 600 Target
P01 T01 Early 650 Target
我认为这在 R 中应该很容易做到。有什么想法吗？
解决方法
这是一种将每个时间范围扩展到 by=50 个时间段的技术。
基础 R
Time.Bins <- Map(
function(a,b) seq(a,b,by = 50),ceiling(dat$Fixation.Start / 50) * 50,dat$Fixation.End)
out <- cbind(
dat[,c("Participant","Trial","Condition","Fixated.Area")
][ rep(seq_len(nrow(dat)),lengths(Time.Bins)),],Time.Bin = unlist(Time.Bins)
)
head(out,20)
# Participant Trial Condition Fixated.Area Time.Bin
# 1 P01 T01 Early Outside 50
# 1.1 P01 T01 Early Outside 100
# 1.2 P01 T01 Early Outside 150
# 1.3 P01 T01 Early Outside 200
# 2 P01 T01 Early Competitor 300
# 2.1 P01 T01 Early Competitor 350
# 2.2 P01 T01 Early Competitor 400
# 2.3 P01 T01 Early Competitor 450
# 3 P01 T01 Early Target 500
# 3.1 P01 T01 Early Target 550
# 3.2 P01 T01 Early Target 600
# 3.3 P01 T01 Early Target 650
# 3.4 P01 T01 Early Target 700
# 3.5 P01 T01 Early Target 750
# 3.6 P01 T01 Early Target 800
# 3.7 P01 T01 Early Target 850
# 4 P01 T02 Late Outside 50
# 4.1 P01 T02 Late Outside 100
# 4.2 P01 T02 Late Outside 150
# 4.3 P01 T02 Late Outside 200
dplyr
library(dplyr)
out <- dat %>%
rowwise() %>%
summarize(
Participant,Trial,Condition,Fixated.Area,Time.Bin = seq(ceiling(Fixation.Start / 50) * 50,Fixation.End,.groups = "drop"
)
out
# # A tibble: 64 x 5
# Participant Trial Condition Fixated.Area Time.Bin
# <chr> <chr> <chr> <chr> <dbl>
# 1 P01 T01 Early Outside 50
# 2 P01 T01 Early Outside 100
# 3 P01 T01 Early Outside 150
# 4 P01 T01 Early Outside 200
# 5 P01 T01 Early Competitor 300
# 6 P01 T01 Early Competitor 350
# 7 P01 T01 Early Competitor 400
# 8 P01 T01 Early Competitor 450
# 9 P01 T01 Early Target 500
# 10 P01 T01 Early Target 550
# # ... with 54 more rows
固定时间=250
您的预期输出在时间=250 时显示“竞争对手”，但数据不支持。如果您需要 250（有或没有区域），那么您可以通过这种方式进行插值。
expbins <- do.call(rbind,by(out,out[,"Condition")],FUN = function(z) {
rng <- seq(min(z$Time.Bin),max(z$Time.Bin),by = 50)
transform(z[rep(1,length(rng)),Fixated.Area = NULL,Time.Bin = rng)
}))
out2 <- merge(expbins,out,by = c("Participant","Time.Bin"),all = TRUE)
head(out2,10)
# Participant Trial Condition Time.Bin Fixated.Area
# 1 P01 T01 Early 50 Outside
# 2 P01 T01 Early 100 Outside
# 3 P01 T01 Early 150 Outside
# 4 P01 T01 Early 200 Outside
# 5 P01 T01 Early 250 <NA>
# 6 P01 T01 Early 300 Competitor
# 7 P01 T01 Early 350 Competitor
# 8 P01 T01 Early 400 Competitor
# 9 P01 T01 Early 450 Competitor
# 10 P01 T01 Early 500 Target
将 time=250 表示为 NA，这是一个未知状态（更好，imo）。
Dplyr，相同：
out %>%
group_by(Participant,Condition) %>%
summarize(
Time.Bin = seq(min(Time.Bin),max(Time.Bin),.groups = "drop"
) %>%
full_join(out,"Time.Bin"))
# # A tibble: 69 x 5
# Participant Trial Condition Time.Bin Fixated.Area
# <chr> <chr> <chr> <dbl> <chr>
# 1 P01 T01 Early 50 Outside
# 2 P01 T01 Early 100 Outside
# 3 P01 T01 Early 150 Outside
# 4 P01 T01 Early 200 Outside
# 5 P01 T01 Early 250 <NA>
# 6 P01 T01 Early 300 Competitor
# 7 P01 T01 Early 350 Competitor
# 8 P01 T01 Early 400 Competitor
# 9 P01 T01 Early 450 Competitor
# 10 P01 T01 Early 500 Target
# # ... with 59 more rows
数据：
dat <- structure(list(Participant = c("P01","P01","P02","P02"),Trial = c("T01","T01","T02","T02"),Condition = c("Early","Early","Late","Late"),Fixation.Start = c(4L,258L,496L,4L,838L,1046L,232L,494L,238L,524L),Fixation.End = c(206L,476L,882L,794L,1026L,1328L,168L,452L,738L,176L,466L,632L),Fixated.Area = c("Outside","Competitor","Target","Outside","Competitor")),class = "data.frame",row.names = c(NA,-12L))
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