Tweet

Pocket

1つの配列内で重複する要素とその個数を出力する方法です。

javascript

var myCurrentArray = new Array("tokyo", "osaka", "nagoya", "tokyo", "okinawa", "tokyo", "osaka");

var counts = {};

for(var i=0;i< myCurrentArray.length;i++) {
	var key = myCurrentArray[i];
	counts[key] = (counts[key])? counts[key] + 1 : 1 ;
}

for (var key in counts) {
	console.log(key + " : " + counts[key]);
}