subsetting: Subsetting objects created using swfscDAS

In swfscDAS: Southwest Fisheries Science Center Shipboard DAS Data Processing

Subsetting objects created using swfscDAS

Description

Subsetting das_dfr or das_df objects

Usage

## S3 method for class 'das_dfr'
x[i, j, ..., drop = TRUE]

## S3 replacement method for class 'das_dfr'
x$name <- value

## S3 replacement method for class 'das_dfr'
x[i, j, ...] <- value

## S3 replacement method for class 'das_dfr'
x[[i]] <- value

## S3 method for class 'das_df'
x[i, j, ..., drop = TRUE]

## S3 replacement method for class 'das_df'
x$name <- value

## S3 replacement method for class 'das_df'
x[i, j, ...] <- value

## S3 replacement method for class 'das_df'
x[[i]] <- value

Arguments

x	object of class das_dfr or das_df
i, j, ...	elements to extract or replace, see [.data.frame
drop	logical, see [.data.frame
name	A literal character string or ..., see [.data.frame
value	A suitable replacement value, see [.data.frame

Details

When subsetting a das_dfr or das_df object, henceforth a das_ object, using any of the functions described in [.data.frame, then then the das_ class is simply dropped and the object is of class data.frame. This is because of the strict format requirements of das_ objects; it is likely that a subsetted das_ object will not have the format required by subsequent swfscDAS functions, and thus it is safest to drop the das_ class. If a data frame is passed to downstream swfscDAS functions that require a das_ object, then they will attempt to coerce the object to the necessary das_ class See as_das_dfr and as_das_df for more details.

Examples

y <- system.file("das_sample.das", package = "swfscDAS")
y.read <- das_read(y)

# All return a data frame:
class(y.read[1:10, ])
class(y.read[, 1:10])

y.df <- y.read
y.df[, 1] <- "a"
class(y.df)

y.df <- y.read
y.df$Event <- "a"
class(y.df)

y.df <- y.read
y.df[["Event"]] <- "a"
class(y.df)

swfscDAS documentation built on Aug. 10, 2023, 9:06 a.m.