Subset a MultiPhysioExperiment by time range and/or modality

Provides flexible subsetting of MultiPhysioExperiment objects:

• mpe[, "eeg"] – select modalities by name, returns a new MPE

• mpe[c(1.0, 5.0), ] – select a time window in seconds across all modalities, accounting for each modality's sampling rate

• mpe[c(1.0, 5.0), "eeg"] – both time and modality subsetting

Usage

# S4 method for class 'MultiPhysioExperiment,ANY,ANY,ANY'
x[i, j, ..., drop = FALSE]

Arguments

x

A MultiPhysioExperiment object.

i

Numeric vector of length 2 specifying time range [tmin, tmax] in seconds, or missing.

j

Character vector of modality names, or missing.

...

Additional arguments (not used).

drop

Logical (not used).

Value

A MultiPhysioExperiment object with the selected modalities and/or time windows.

Details

When i is a numeric vector of length 2, it is interpreted as a time range [tmin, tmax] in seconds. For each modality, the appropriate sample indices are computed from its sampling rate: start_idx = floor(tmin * sr) + 1, end_idx = floor(tmax * sr) + 1, clamped to valid bounds.

Examples

eeg_data <- matrix(rnorm(2500 * 4), nrow = 2500, ncol = 4)
emg_data <- matrix(rnorm(5000 * 2), nrow = 5000, ncol = 2)
pe_eeg <- PhysioExperiment(
  assays = list(raw = eeg_data),
  samplingRate = 500
)
pe_emg <- PhysioExperiment(
  assays = list(raw = emg_data),
  samplingRate = 1000
)
mpe <- MultiPhysioExperiment(EEG = pe_eeg, EMG = pe_emg)

# Subset by modality
mpe_eeg <- mpe[, "EEG"]
modalities(mpe_eeg)  # "EEG"
#> [1] "EEG"

# Subset by time range (seconds)
mpe_win <- mpe[c(1.0, 3.0), ]

# Combined
mpe_sub <- mpe[c(1.0, 3.0), "EEG"]