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# 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

See Also

`orch.pack`

Example

This code fragment creates a mapper function using `orch.keyval`:

    hadoop.run(data,
         mapper = function(k,v) {
            orch.keyval(k,v)
         })