Using inject with a map to count occurrences of strings

injectCountExample.groovy

import groovy.json.JsonOutput

// File is just a list of words, one per line.
def counts = new File("types.txt").readLines().inject([:]) {Map obj, String val ->
    // If we hit an empty line, do nothing and just return the map as-is
    if (val) {
        if (!obj[val]) {
            // The key didn't exist, so put it into the map
            obj[val] = 1
        } else {
            // Increment the counter
            obj[val]++
        }
    }

    obj // Return the map when we are done
}

// Print the counts
println JsonOutput.prettyPrint(JsonOutput.toJson(counts))

Nice example of how to use inject. I found it can be combined with Map default values for even more Groovy goodness:

    import groovy.json.JsonOutput

    // File is just a list of words, one per line. 

    def counts = new File("/tmp/types.txt").readLines().inject([:]) {Map obj, String val ->
        // If we hit an empty line, do nothing and just return the map as-is
        if (val) {
            obj.get(val, 0)
            obj[val]++
        }

        obj // Return the map when we are done
    }

    // Print the counts
    println JsonOutput.prettyPrint(JsonOutput.toJson(counts))