which.nc: "which" for NetCDF arrays

In CJBarry/Rflow: Tools for analysing and writing input and output files for USGS MODFLOW

Description

A version of "which" for NetCDF datasets that does not require prior loading of arrays and avoids loading the whole of large arrays at once.

Usage

which.nc(ncfile, variable, FUN = Negate(is.na), ..., arr.ind = FALSE,
  useNames = TRUE, size.threshold = 1e+07)

Arguments

ncfile	NetCDF connection object
variable	variable name within NetCDF data set
FUN	function to operate on array, which should produce a logical vector or array
...	additional arguments to FUN
arr.ind, useNames	passed to which
size.threshold	how large can the array be before the function performs on chunks?

Value

integer vector (arr.ind = FALSE) or matrix (arr.ind = TRUE), as with 'which'

Examples

library(RNetCDF)

mfdata <- open.nc(system.file("rflow_mf_demo.nc", package = "Rflow"))

# find which cells have a well in, by C, R, L reference
unique(which.nc(mfdata, "Wells", `!=`, 0, arr.ind = TRUE)[, 1:3],
       MARGIN = 1L)

CJBarry/Rflow documentation built on June 16, 2019, 12:35 p.m.