通过迭代我需要使用 javascript 过滤特定的单词，但我没有得到预期的值？

Question

我只需要过滤类别类型，而是我的代码返回定义的字符串。我的预期输出是：家具沙发厨房。var contextstr =  'Lorem Ipsum is category:funiture dummy text of the printing and typesetting industry. Lorem Ipsum has been the industrys standard dummy text ever since category:sofa 1500s, when an unknown printer took a category:galley of type and scrambled it to make a type';var count = 0;while (true) {  var findpos = contextstr.indexOf('category:', count);  if (findpos == -1) break;  var startpos = findpos + 9;  var endpos = contextstr.indexOf(' ', startpos);  var printcat = contextstr.substring(startpos + endpos);  document.write(printcat + '<br>');  //x++;  count = endpos + 1;}

Answer 1

试试这个：

var contextstr =

  'Lorem Ipsum is category:funiture dummy text of the printing and typesetting industry. Lorem Ipsum has been the industrys standard dummy text ever since category:sofa 1500s, when an unknown printer took a category:galley of type and scrambled it to make a type';

var splitArray = contextstr.split("category:");

splitArray.shift(); //Remove first item (Stuff right before first 'category:')

splitArray.forEach(split => {

  document.write(split.split(" ")[0] + '<br>');

});

Answer 2

改变这一行：

var printcat = contextstr.substring(startpos + endpos);

到：

var printcat = contextstr.substring(startpos,endpos);

var contextstr =

    

'Lorem Ipsum is category:funiture dummy text of the printing and typesetting industry. Lorem Ipsum has been the industrys standard dummy text ever since category:sofa 1500s, when an unknown printer took a category:galley of type and scrambled it to make a type';

var x = 1;

var count = 0;

while (x=1) {

  var findpos = contextstr.indexOf('category:', count);

  if (findpos == -1) break;

  

  var startpos = findpos + 9;

  var endpos = contextstr.indexOf(' ', startpos);

  

  var printcat = contextstr.substring(startpos, endpos);

  

 document.write(printcat + '<br>');

  //x++;

  count = endpos + 1;

}

Answer 3

试试这个：

const contextstr =

  'Lorem Ipsum is category:funiture dummy text of the printing and typesetting industry. Lorem Ipsum has been the industrys standard dummy text ever since category:sofa 1500s, when an unknown printer took a category:galley of type and scrambled it to make a type';

const matches = [...contextstr.matchAll(/(?<=category:)\S+/g)];

document.write(`${matches.join('\n')}<br>`);

的解释/(?<=category:)\S+/g

/

  (?<=         positive lookbehind

    category:  matches anything with category: before it

  )            end of positive lookbehind

  \S           matches anything that's not a whitespace character

    +          ...if there are one or more of them

/g             global flag: match multiple times