nws (version 1.6.2)

nwsIFetchTry: netWorkSpace Class Method

Description

Create a function that acts as a destructive iterator over the values of the specified variable.

Usage

## S3 method for class 'netWorkSpace':
nwsIFetchTry(.Object, xName, defaultVal=NULL)

Arguments

.Object

a netWorkSpace class object

xName

name of the variable to be fetched

defaultVal

value to return, if xName is not found in the netWorkSpace

Details

The iterator function returned by the nwsIFetchTry method takes no arguments, and works just like the nwsFetchTry method, specified with the same arguments that were passed to nwsIFetchTry method. Note that the nwsIFind and nwsIFindTry methods are much more useful, since they provide the only way to iterate over values of a variable non-destructively. nwsIFetch and nwsIFetchTry are provided for completeness.

See Also

nwsFetchTry, nwsIFetch

Examples

ws <- netWorkSpace('nws example')
nwsStore(ws, 'x', 10)
it <- nwsIFetchTry(ws, 'x', NA)
it()  # returns the value 10
it()  # returns NA