dcut {emuR}

Function to extract a vector or matrix from EMU-Trackdata at a single time point of to create another EMU-trackdata object between two times.

Description

A general purpose tool for extracting data from track objects either at a particular time, or between two times. The times can be values in milliseconds or proportional times between zero (the onset) and one (the offset).

Usage

dcut(
  trackdata,
  left.time,
  right.time,
  single = TRUE,
  average = TRUE,
  prop = FALSE
)

Arguments

trackdata

An Emu trackdata object.

left.time

Either: a numeric vector of the same length as there are observations in trackdata. Or: a single value between 0 and 1. In the first case, the left time boundary of trackdata[n,] is cut at left.time[n], in the second case, and if prop=TRUE, it is cut at that proportional time.

right.time

Either: a numeric vector of the same length as there are observations in trackdata. Or: a single value between 0 and 1. In the first case, the right time boundary of trackdata[n,] is cut at right.time[n], in the second case, and if prop=TRUE, it is cut at that proportional time.

single

If TRUE, one value is returned per segment. This applies when the requested time falls between two track frames. When single=TRUE, the preceding value is returned, unless average=TRUE (see below), in which case the average value of the two frames is returned. when the right.time argument is omitted

average

A single element logical vector - see single above. Applies only when the right.times argument is omitted and when single = TRUE

prop

If TRUE left.time and right.time are interpreted as proportions, if FALSE, they are interpreted as millisecond times

Details

This function extracts data from each segment of a trackdata object.

If 'prop=FALSE' the time arguments ('left.time' and 'right.time') are interpreted as millisecond times and each should be a vector with the same length as the number of segments in 'trackdata'. If 'prop=TRUE' the time arguments should be single values between zero (the onset of the segment) and one (the offset).

If 'right.time' is omitted then a single data point corresponding to 'left.time' for each segment is returned.

Value

A trackdata object if both 'left.time' and 'right.time' are specified, otherwise a matrix if 'right.time' is unspecified and the trackdata object has multiple columns of data or a vector if right.time' is unspecified and the trackdata object has a single column of data.

Author(s)

Jonathan Harrington

See Also

get_trackdata, dplot, eplot

Examples

     # the data values of the trackdata object at the temporal midpoint
     # (midvals is matrix of F1 and F2 data)
     dip.fdat[1:10]
     midvals <- dcut(dip.fdat, 0.5, prop=TRUE)
     midvals[1:10,]
     
     
     # the data values of the trackdata object between 
     # extending from 20
     # (bet is a trackdata object of F1 and F2 values)
     bet <- dcut(dip.fdat, 0.2, 0.8, prop=TRUE)
     bet[1]
     

     # the data values of the trackdata object at 30 ms after
     # the start time of the trackdata object
     # (time30 is a matrix of F1 and F2 data
     times <- dip.fdat$ftime[,1]+30
     times[1:10]
     time30 <- dcut(dip.fdat, times)
     time30[1:10]
     

     # the data values of the trackdata object 
     # between the  start time and 30 ms after the start  time
     # (int is a trackdata object of F1 and F2 values extending
     # from the start of the diphthongs up to 30 ms after the diphthongs)
     int <- dcut(dip.fdat, dip.fdat$ftime[,1], times)
     int[1]