Groovy高效编程——统计单词频率

　　def content =
　　"""

　　The Java Collections API is the basis for all the nice support that Groovy gives you
　　through lists and maps. In fact, Groovy not only uses the same abstractions, it
　　even works on the very same classes that make up the Java Collections API.
　　"""

　　def words = content.tokenize()
　　def wordFrequency = [:]
　　words.each {
　　wordFrequency[it] = wordFrequency.get(it, 0 ) + 1
　　}
　　def wordList = wordFrequency.keySet().toList()
　　wordList.sort {wordFrequency[it]}
　　def result = ''
　　wordList[ - 1 .. - 6 ].each {
　　result += it.padLeft( 12 ) + " : " + wordFrequency[it] + " \n "
　　}
　　println result