emuR (version 2.5.0)

dcut: 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
)

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.

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

Author

Jonathan Harrington

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.

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]