javascript - 如何拆分字符串包含javascript中的分隔符？

Question

我有类似“1 + 2 - 3 + 10”的字符串。我想将它拆分为 "1"、"+2"、"-3"、"+10"。

这是我的代码。

var expression = "1 + 2 - 3 + 10";
expression = expression.replace(/\s+/g, '');
let fields = expression.split(/([+-]\d+)/g);
console.log(fields);

但是结果是

["1", "+2", "", "-3", "", "+10", ""]

如何生成结果 ["1", "+2", "-3", "+10"]？

Answer 1

你的正则表达式需要一个组

/([+-]\d+)/
 ^       ^  group 

包含在结果集中。

作为结果，对于后续的每次迭代，您都会得到两个部分，即来自组的先前部分和组本身。

"1"    first find
"+2"   group as separator for splitting, included to result set
 ""    second find, empty because of the found next separator
"-3"   second separator/group
""     third part without separator
"+10"  third separator
""     rest part between separator and end of string

---

您可以通过运算符(operator)的积极前瞻来拆分。

const
    string = '1 + 2 - 3 + 10',
    result = string.replace(/\s+/g, '').split(/(?=[+-])/);

console.log(result);