Question

array = ['blue', 'red', 'green', 'green', 'red', 'blue', 'black', 'blue']

…the output I’m trying to achieve would result in

output = ['blue x3', 'red x2', 'green x2', 'black']

I’m having a hard time figuring out the most effective way to do this.

Thanks!

Answer 1

 var array = ['blue', 'red', 'green', 'green', 'red', 'blue', 'black', 'blue'] 

 var hash = {};
 for( var i = 0; i < array.length; ++i){
     hash[array[i]] = (!hash.hasOwnProperty(array[i]) ? 1 : hash[array[i]]+1);
 }

 var output = [];
 for(var key in hash){
     output.push( key + (hash[key]>1 ? (" x"+hash[key]):"") );
 }
 console.log( output ); //["blue x3", "red x2", "green x2", "black"]

DEMO