rsp.reshape: Reshaping respeciate data sets

In atmoschem/respeciate: Speciation profiles for gases and aerosols

Reshaping respeciate data sets

Description

Functions for reshaping respeciate profiles

rsp_dcast and rsp_melt_wide reshape supplied respeciate profile(s). rsp_dcast converts these from their supplied long form to a widened form, dcasting the data set by either species or profiles depending on the widen setting applied. rsp_dcast_profile, rsp_dcast_profile_id, rsp_dcast_species and rsp_dcast_species_id are wrappers for these options. rsp_melt_wide attempts to return a previously widened data set to the original long form.

Usage

rsp_dcast(rsp, widen = "species")

rsp_dcast_profile(rsp, widen = "profile")

rsp_dcast_profile_id(rsp, widen = "profile.id")

rsp_dcast_species(rsp = rsp, widen = "species")

rsp_dcast_species_id(rsp = rsp, widen = "species.id")

rsp_melt_wide(rsp, pad = FALSE, drop.nas = FALSE)

Arguments

rsp	A respeciate object, a data.frame of respeciate profiles in standard long form or widened form using rsp_dcast and rsp_melt_wide, respectively.
widen	character, when widening rsp with rsp_dcast, the data type to dcast, currently 'species' (default), 'species.id', 'profile' or 'profile.id'. See Note.
pad	logical or character, when melting a previously widened data set, should output be re-populated with species and/or profile meta-data, discarded when widening. This is currently handled by rsp_pad. The default FALSE does not pad, TRUE pads, applies standard settings, so does not include profile sources reference meta-data. (See rsp_pad for other options).
drop.nas	logical, when melting a previously widened data set, should output be stripped of any rows containing empty weight/value columns. Because not all profile contains all species, the dcast/melt process can generate empty rows, and this step attempt account for that when working with standard reSPECIATE profiles. It is, however, sometimes useful to check first, e.g. when building profiles yourself.

Value

rsp_dcast returns the wide form of the supplied respeciate profile. rsp_melt_wide returns the (standard) long form of a previously widened profile.

Note

Conventional long-to-wide reshaping of data, or dcasting, can be slow and memory inefficient. So, respeciate uses the data.table::dcast method. The rsp_dcast_species method, applied using widen='species', is effectively:

dcast(..., profile.id+.profile~.species, value.var=".value")

And, the alternative widen='profile':

dcast(..., species.id+.species~.profile, value.var=".value")

respeciate uses a local version of the SPECIATE and SPECIEUROPE weight measurements .value, so the EPA and JCR source information can easily be recovered. See also rsp_rescale_profile.

References

Dowle M, Srinivasan A (2023). _data.table: Extension of 'data.frame'_. R package version 1.14.8, <https://CRAN.R-project.org/package=data.table>.

atmoschem/respeciate documentation built on April 3, 2025, 4:25 p.m.