var a = {
		1: 'a',
		2: 'b',
		3: 'c',
		4: 'd'
	}

	var keys = Object.keys(a)
	var values = Object.values(a)
	console.log(keys , values)

# 建议使用
console.log(Object.keys(a)[2] + ':' + Object.values(a)[2])

#无意义
console.log(Object.keys(a)[3] + ':' + a[Object.keys(a)[3]])