R:根据时间列每次试验的排名变量

Question

我的数据如下所示:

Subject  Trial  Task  Time  Fixation
..
1        1       2    1      0.335
1        1       2    456    NA
1        1       2    765    0.165
1        1       2    967    0.445
..
2        3       1    1      0.665
2        3       1    300    0.556
2        3       1    570    NA
2        3       1    900    NA
..
15       5       3    1      0.766
15       5       3    567    0.254
15       5       3    765    0.167
15       5       3    1465   NA
..

我想创建一个列 FixationID，我想根据时间列(1,2,3,4..)对每个试验 的每个 Fixation 进行排名。时间列以毫秒为单位显示每个试验的时间进程，每个试验从 1 开始。试验有不同的长度。

我希望我的数据看起来像这样:

Subject  Trial  Task  Time  Fixation FixationID
..
1        1       2    1      0.335    1
1        1       2    456    NA       NA
1        1       2    765    0.165    2
1        1       2    967    0.445    3
..
2        3       1    1      0.665    1
2        3       1    300    0.556    2
2        3       1    570    NA       NA
2        3       1    900    NA       NA
..
15       5       3    1      0.766    1
15       5       3    567    0.254    2
15       5       3    765    0.167    3
15       5       3    1465   NA       NA
..

我试过

library(data.table)
setDT(mydata)[!is.na(Fixation), FixID := 
              seq_len(.N)[order(Time)], by = Trial]

但我得到的是 1,16,31,45,57.. 对于我的 Subject 1 Trial 1. 我想要 1,2,3,4,5..

谁能帮我这个？

摘自我的数据:

structure(list(Subject = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L), Trial = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 2L, 2L, 2L, 2L), Task = c(2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L), Time = c(1L, 385L, 571L, 638L, 951L, 
1020L, 1349L, 1401L, 1661L, 1706L, 2042L, 2067L, 2322L, 2375L, 
2540L, 2660L, 2686L, 3108L, 3172L, 3423L, 3462L, 3845L, 3870L, 
3969L, 4099L, 4132L, 1L, 471L, 513L, 697L), Fixation = c(0.383, 
0.185, NA, 0.312, NA, 0.328, NA, 0.259, NA, 0.335, NA, 0.254, 
NA, 0.164, 0.119, NA, 0.421, NA, 0.25, NA, 0.382, NA, 0.0979999999999999, 
0.129, NA, 0.335, 0.469, NA, 0.183, NA)), .Names = c("Subject", 
"Trial", "Task", "Time", "Fixation"), row.names = c(NA, 30L), class = "data.frame")

Answer 1

那这个呢:

library(data.table)
setDT(mydata)
mydata[!is.na(Fixation), FixID := frank(Time), by = Trial]

head(mydata, 10)
    Subject Trial Task Time Fixation FixID
 1:       1     1    2    1    0.383     1
 2:       1     1    2  385    0.185     2
 3:       1     1    2  571       NA    NA
 4:       1     1    2  638    0.312     3
 5:       1     1    2  951       NA    NA
 6:       1     1    2 1020    0.328     4
 7:       1     1    2 1349       NA    NA
 8:       1     1    2 1401    0.259     5
 9:       1     1    2 1661       NA    NA
10:       1     1    2 1706    0.335     6

tail(mydata, 10)
    Subject Trial Task Time Fixation FixID
 1:       1     1    2 3462    0.382    12
 2:       1     1    2 3845       NA    NA
 3:       1     1    2 3870    0.098    13
 4:       1     1    2 3969    0.129    14
 5:       1     1    2 4099       NA    NA
 6:       1     1    2 4132    0.335    15
 7:       1     2    2    1    0.469     1
 8:       1     2    2  471       NA    NA
 9:       1     2    2  513    0.183     2
10:       1     2    2  697       NA    NA