subset.swmpr: Subset a swmpr object

In SWMPr: Retrieving, Organizing, and Analyzing Estuary Monitoring Data

Subset a swmpr object

Description

Subset a swmpr object by a date range, parameters, or non-empty values

Usage

## S3 method for class 'swmpr'
subset(
  x,
  subset = NULL,
  select = NULL,
  operator = NULL,
  rem_rows = FALSE,
  rem_cols = FALSE,
  ...
)

Arguments

x	input swmpr object
subset	chr string of form 'YYYY-mm-dd HH:MM' to subset a date range. Input can be one (requires operator or two values (a range).
select	chr string of parameters to keep, 'datetimestamp' will always be kept
operator	chr string specifiying binary operator (e.g., '>', '<=') if subset is one date value
rem_rows	logical indicating if rows with no data are removed, default FALSE
rem_cols	is logical indicating if cols with no data are removed, default FALSE
...	arguments passed to other methods

Details

This function is used to subset swmpr data by date and/or a selected parameter. The date can be a single value or as two dates to select records within the range. The former case requires a binary operator input as a character string passed to the argument, such as > or <. The subset argument for the date(s) must also be a character string of the format YYYY-mm-dd HH:MM for each element (i.e., %Y-%m-%d %H:%M in POSIX standards). Be aware that an error may be returned using this function if the subset argument is in the correct format but the calendar date does not exist, e.g. '2012-11-31 12:00'. The function can also be used to remove rows and columns that do not contain data, which may be useful after processing with other functions.

Value

Returns a swmpr object as a subset of the input. The original object will be returned if no arguments are specified.

See Also

subset

Examples

## get data
data(apaebmet)
dat <- apaebmet

## subset records greater than or equal to a date
subset(dat, subset = '2013-01-01 0:00', operator = '>=')

## subset records within a date range, select two parameters
subset(dat, subset = c('2012-07-01 6:00', '2012-08-01 18:15'),
   select = c('atemp', 'totsorad'))

SWMPr documentation built on July 26, 2023, 5:20 p.m.