将字符串拆分为n个单词的数组

Question

我试图改变这个:

"This is a test this is a test"

进入这个:

["This is a", "test this is", "a test"]

我试过这个:

const re = /\b[\w']+(?:[^\w\n]+[\w']+){0,2}\b/
const wordList = sample.split(re)
console.log(wordList)

但我得到了这个:

[ '',
  ' ',
  ' ']

为什么是这样？

(规则是每N个字分割字符串.)

Answer 1

该String#split方法将按匹配的内容拆分字符串,因此它不会在结果数组中包含匹配的字符串.

在正则表达式上使用String#match带有全局标志(g)的方法:

var sample="This is a test this is a test"

const re = /\b[\w']+(?:\s+[\w']+){0,2}/g;
const wordList = sample.match(re);
console.log(wordList);

正则表达式在这里解释.

Answer 2

作为替代方法，您可以按空间拆分字符串并批量合并块。

function splitByWordCount(str, count) {
  var arr = str.split(' ')
  var r = [];
  while (arr.length) {
    r.push(arr.splice(0, count).join(' '))
  }
  return r;
}

var a = "This is a test this is a test";
console.log(splitByWordCount(a, 3))
console.log(splitByWordCount(a, 2))