Description Usage Arguments Value Examples
This function is useful if some critical event occurs each trial, and we would like to adjust the timestamps so that they are relative to that event time.
1 2 3 4 5 6 7 8 9 | adjust_times(
data,
time_var = Time,
event_var = NULL,
...,
align = TRUE,
fps = 60,
ties = "first"
)
|
data |
a long data frame of looking data |
time_var |
a column in |
event_var |
a column in |
... |
grouping variables. The grouping variables should uniquely specify a trial of eyetracking data. |
align |
whether to align the eyetracking times so that the frame closest to the event time gets time = 0. |
fps |
the eyetracking sampling rate. Defaults to 60 frames per second. |
ties |
how to break ties when the smallest times are equally close to
zero. Default is |
the looking data with the times adjusted by event times. By default, these times are aligned so that the frame closest to the event time gets value 0.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | # Consider some raw tims from an eyetrack. For each trial, some critical
# event occurs and we have a column with the time of that event for each
# trial.
trial1 <- data.frame(trial = 1, time_ms = 1:5, event = 2)
trial2 <- data.frame(trial = 2, time_ms = 6:10, event = 8.5)
trial_times <- dplyr::bind_rows(trial1, trial2)
trial_times
# We want to adjust the times so that time 0 is time of the critical event.
adjust_times(trial_times, time_ms, event, trial, fps = 1000)
# The times are adjusted so that the frame closest to the event time gets
# the time zero. Setting `align` to `FALSE` skips this behavior.
adjust_times(trial_times, time_ms, event, trial, align = FALSE, fps = 1000)
# In the second trial there is a tie. Two frames are equally close to 0. By
# default the first frame is chosen to be zero, but setting `ties` to
# `"last"` will break ties with the later frame.
adjust_times(trial_times, time_ms, event, trial, ties = "last", fps = 1000)
|
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