如何使用JavaScript動態創建數組？

Question

我有這種形式的數組

['203,448', '204,297', '204,448', '205,297', '230,448', '231,297', '24,448', '24,297','203,548', '204,548', '204,548' ]

需求輸出：

0:['203,448',  '204,448', '230,448','24,448', ]
1: [ '204,297',  '205,297', '231,297', '24,297']
2: ['203,548', '204,548', '204,548']

我想sepreate 2 featur的即203，448和204，297基極上的元素

Answer 1

您可以將哈希表用於字符串的第二部分，並在數組中收集相同的項。

 var data = ['203,448', '204,297', '204,448', '205,297', '230,448', '231,297', '24,448', '24,297', '203,548', '204,548', '204,548'], hash = Object.create(null), result = data.reduce(function (r, a) { var key = a.split(',')[1]; if (!hash[key]) { hash[key] = []; r.push(hash[key]); } hash[key].push(a); return r; }, []); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

對於僅放置第一部分，可以使用拆分數組

 var data = ['203,448', '204,297', '204,448', '205,297', '230,448', '231,297', '24,448', '24,297', '203,548', '204,548', '204,548'], hash = Object.create(null), result = data.reduce(function (r, a) { var s = a.split(','); if (!hash[s[1]]) { hash[s[1]] = []; r.push(hash[s[1]]); } hash[s[1]].push(s[0]); return r; }, []); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; }