ds.look {dsBaseClient}R Documentation

ds.look

Description

The function is a wrapper for the 'opal' package function 'datashield.aggregate'.

Usage

ds.look(toAggregate = NULL, checks = FALSE, datasources = NULL)

Arguments

toAggregate

a character string specifying the function call to be made(see above)

checks

a Boolean object indicating whether optional checks are to be undertaken in this instance only one check is specified - to check that a "toAggregate" expression has been specified, nevertheless this is defaulted to FALSE to be consistent with other functions and to save a small amount of time.

datasources

specifies the particular opal object(s) to use. If the <datasources> argument is not specified the default set of opals will be used. The default opals are called default.opals and the default can be set using the function ds.setDefaultOpals. If the <datasources> is to be specified, it should be set without inverted commas: e.g. datasources=opals.em or datasources=default.opals. If you wish to apply the function solely to e.g. the second opal server in a set of three, the argument can be specified as: e.g. datasources=opals.em[2]. If you wish to specify the first and third opal servers in a set you specify: e.g. datasources=opals.em[c(1,3)]

Details

the function ds.look can be used to make a direct call to a server side' aggregate function more simply than using the datashield.aggregate function. The ds.look and datashield.aggregate functions are generally only recommended for experienced developers. For example, the toAggregate argument has to be expressed in the same form that the serverside function would usually expect from its clientside pair. For example: ds.look("table1DDS(female)") works. But, if you express this as ds.look("table1DDS('female')") it won't work because although when you call this same function using its clientside function you write ds.table1D('female') the inverted commas are stripped off during processing by the clientside function so the call to the serverside does not contain inverted commas. Apart from during development work (e.g. before a clientside function has been written) it is almost always easier and less error prone to call a serverside function using its client-side pair.

Value

the output from the specified server side aggregate function to the client side

Author(s)

Gaye, A, Burton PR.


[Package dsBaseClient version 5.0.0 ]