orch.keyval
Outputs key-value pairs in a MapReduce job.
Usage
orch.keyval(
key,
value)
Arguments
- key
-
A scalar value.
- value
-
A data structure such as a scalar, list, data frame, or vector.
Usage Notes
This function can only be used in the mapper
, reducer
, or combiner
arguments of hadoop.exec
and hadoop.run
. Because the orch.keyval
function is not exposed in the ORCH
client API, you cannot call it anywhere else.
Return Value
(key, value) structures
Example
This code fragment creates a mapper function using orch.keyval
:
hadoop.run(data,
mapper = function(k,v) {
orch.keyval(k,v)
})