word counter

word_counter.py

from itertools import groupby


def word_counter(*words):
    '''Write a Python program that inputs a list of words, separated by white-
    space, and outputs how many times each word appears in the list.
    '''
    return {word: len(list(word_group)) for word, word_group in
            groupby(sorted(words), key=lambda x: x)}

Lisp L-99:

(defun encode-modified (list)
  (let ((result    '())
        (count     0)
        (last-item nil))
    (labels ((collect-result ()
               (push (if (= 1 count)
                         last-item
                         (list count last-item))
                     result))
             (new-item (item)
               (setf count 1
                     last-item item))
             (same-item ()
               (incf count))
             (return-result ()
               (when (plusp count)
                 (collect-result))
               (nreverse result)))
      (dolist (item list  (return-result))
        (cond
          ((zerop count)        (new-item item))
          ((eql item last-item) (same-item))
          (t                    (collect-result)
                                (new-item item)))))))
(princ (encode-modified '(galinha coxinha macaco vaca vaca batata batata batata batata)))

(GALINHA COXINHA MACACO (2 VACA) (4 BATATA))

using System;
using System.Linq;
using System.Collections.Generic;

namespace WordCount
{
    class Program
    {
        public static void Main(string[] args)
        {
             String phrase = "vaca batata galinha batata coxinha macaco batata vaca batata";

             List<String> words = phrase.Split ( ' ' ).ToList ();

             foreach ( var group in words.GroupBy ( p => p ) )
                Console.WriteLine ( "{0} - {1}", group.Key, group.Count ());
        }
    }
}

Groovy:

def wordCount(text) {
    def map = [:]
    def words = text.split(" ")
    words.each() { word -> 
        map.putAt(word, map.get(word, 0) + 1)
    }
    map
}

def text = "vaca batata galinha batata coxinha macaco batata vaca batata"

def map = wordCount(text)

map.each { key, value -> println """${key}: ${value} """ }

Shell script, using arguments:

#!/bin/sh
echo $@ | tr ' ' '\n' | sort | uniq -c

e.g.:

./wordcounter.sh vaca batata galinha batata coxinha macaco batata vaca batata

http://pastebin.com/ZTdJcKC8

Javascript:

function word_counter(words) {
  var counter = {};

  words.split(' ').map(function(word) {
    !counter[word] ? counter[word] = 1 : counter[word] += 1;
  });

  return counter;
}

var frase = 'vaca batata galinha batata coxinha macaco batata vaca batata';

word_counter(frase); 
// => Object {vaca: 2, batata: 4, galinha: 1, coxinha: 1, macaco: 1}

Scala

object Test extends App{

  def count(text: String): Map[String, Int] = {
    def count(words: Array[String]): Map[String, Int] = {
      if(words.size == 1) {
        return Map(words.head -> 1)
      } else {
        val map = count(words.tail)
        return map + (words.head -> (map.getOrElse(words.head, 0) + 1))
      }
    }
    return count(text.split(" "))
  }

  println(count("vaca batata galinha batata coxinha macaco batata vaca batata"))
}

Outra versão em python....:

def word_counter(string):
    return {x: string.count(x) for x in string.split()}

Outra versão ainda mais simples:

import collections


def word_counter(*string):
    return dict(collections.Counter(string).items())