pems.utils (version 0.2.29.1)

2.1.pems.structure: 'pems' object structure

Description

This pages provides a brief outview description of the 'pems' object structure. It also lists some associated functions

Usage

getPEMSElement(x, pems = NULL, units = NULL, ..., 
            fun.name="getPEMSElement", 
            if.missing = "stop", if.null = if.missing, 
            track.name = TRUE, .x = enquo(x))
getPEMSData(pems=NULL, ..., fun.name = "getPEMSData", 
            if.missing = "stop", .pems = enquo(pems))
getPEMSConstants(pems=NULL, ..., 
            fun.name = "getPEMSConstants", 
            if.missing = "stop", .pems = enquo(pems))
pemsData(pems=NULL, ..., 
          fun.name = "pemsData", if.missing = "stop",
          pems.name = deparse(substitute(pems)))
pemsConstants(pems=NULL, ..., 
          fun.name = "pemsConstants", if.missing = "stop",
          pems.name = deparse(substitute(pems)))
pemsHistory(pems=NULL, ..., 
         fun.name = "pemsHistory", if.missing = "stop",
         pems.name = deparse(substitute(pems)))
         
cpe(...)

Value

getPEMSElement returns the requested element of a supplied pems object as a managed vector or

pems.element, if available. If missing, error handling is by checkIfMissing. See

check... for more details.)

pemsData returns the data component of a supplied pems object as a data.frame.

getPEMSData returns the data component of a supplied pems object as a data.frame.

pemsConstants returns the constants component of a supplied pems object as a list.

getPEMSConstants returns the constants component of a supplied pems object as a

list.

pemsHistory returns the history component of a supplied pems object as a list.

cpe turns the concatenated form of supplied input.

Arguments

x

(Required vector, typically pems.element) For getPEMSElement, the required data element.

pems

(pems object) If supplied, the pems object to search for x before checking the parent environments and R workspace.

units

(Optional) The units that x should be supplied in (handled by convertUnits).

...

(Optional) Other Arguments.

fun.name, if.missing, if.null, track.name, pems.name, .x, .pems

(Various) Other options using for pems.utils house-keeping. See check... for definitions, although generally these can be ignored by users. See Note below.

Author

Karl Ropkins

Details

The pems object is a managed data.frame. It has five main components: data, units, constants, history and tags. data is the main data.frame. Each element (named data.frame column) is a data-series of the original PEMS data. units are the associated unit definitions. constants is a list of associated constants that are to be used with the pems object. (The preference order is arguments given in a call then constants declared in the pems object then constant defaults held by the pems.utils package.) history is a log of pems object modifications. tags are any other components that the user wishes to add to a pems object as identifiers.

getPEMSElement gets a requested pem.element from pems if supplied or from the local workspace.

pemsData and getPEMSData get the data component of a supplied pems object.

pemsConstants and getPEMSConstants get all constants locally defined for the supplied pems object.

pemsHistory gets the history of supplied pems object.

cpe combines pems.elements. It is intended as an alternative to c(pems.element, ...) while that generic is in-development.

References

rlang and dplyr package functions now do the heavy lifting for getPEMSElement.

Lionel Henry and Hadley Wickham (2018). rlang: Functions for Base Types and Core R and 'Tidyverse' Features. R package version 0.2.0. https://CRAN.R-project.org/package=rlang

Hadley Wickham, Romain Francois, Lionel Henry and Kirill Muller (2017). dplyr: A Grammar of Data Manipulation. R package version 0.7.4. https://CRAN.R-project.org/package=dplyr

See Also

See Also: check... for check... function equivalents; pems.generics for pems object generic functions.

Examples

###########
##example 1 
###########

#basic usage

#using example data pems.1
#(supplied as part of pems.utils package)

#pems structure
pems.1

# extracting the pems.1 element velocity
getPEMSElement(velocity, pems.1)

if (FALSE) {
#generic (SE) equivalents
pems.1$velocity
pems.1["velocity"] 
}