clip_data {MIMSunit}

Clip dataframe to the given start and stop time

Description

clip_data clips the input sensor dataframe according to the given start and stop time

Usage

clip_data(df, start_time, stop_time)

Arguments

df

dataframe. Input dataframe of the multi-channel signal. The first column is the timestamps in POSXlct format and the following columns are accelerometer values.

start_time

POSXlct format or character. Start time for clipping. If it is a character, it should be recognizable by as.POSXlct function.

stop_time

POSXlct format or character. Stop time for clipping. If it is a character, it should be recognizable by as.POSXlct function.

Details

This function accepts a dataframe of multi-channel signal, clips it according to the start_time and stop_time.

Value

dataframe. The same format as the input dataframe.

How is it used in MIMS-unit algorithm?

This function is a utility function that was used in various part in the algorithm whenever we need to clip a dataframe.

See Also

Other utility functions: cut_off_signal(), interpolate_signal(), parse_epoch_string(), sampling_rate(), segment_data(), simulate_new_data()

Examples

  default_ops = options()
  options(digits.secs=3)
  # Use the provided sample data
  df = sample_raw_accel_data

  # Check the start time and stop time of the dataset
  summary(df)

  # Use timestamp string to clip 1 second data
  start_time = "2016-01-15 11:01:00"
  stop_time = "2016-01-15 11:01:01"
  output = clip_data(df, start_time, stop_time)
  summary(output)

  # Use POSIXct timestamp to clip data
  start_time = as.POSIXct("2016-01-15 11:01:00")
  stop_time = as.POSIXct("2016-01-15 11:01:01")
  output = clip_data(df, start_time, stop_time)
  summary(output)

  # If start and stop time is not in the range of the input data
  # return empty data.frame
  start_time = "2016-01-15 12:01:00"
  stop_time = "2016-01-15 12:01:01"
  output = clip_data(df, start_time, stop_time)
  output

  # Restore original options
  options(default_ops)