Question

我需要获取所选关键字之前的所有字符

例如：

const str = "This is example sentence for this stack overflow question"
const searchTerm =  "stack"

需要什么

expected results = 'for this stack overflow question'

Answer 1

const str = "This is example sentence for this stack overflow question"
const searchTerm =  "stack"

const strings = str.split(" ");
// if you are very sure the str `must` contains searchTerm
const idx = strings.findIndex(item => item==searchTerm);
// if you are very sure the idx `must` greater than 2
console.log(strings.slice(idx-2).join(" "));

Answer 2

您可以分割字符串，然后搜索搜索项的索引。如果index不等于-1，则只需对数组执行连接操作。尝试以下方法。此外，如果搜索词之间用空格隔开，则可以使用replace()替换搜索词。

const str = "This is example sentence for this stack overflow question"
const searchTerm =  "stack overflow";

var strReplace = str.replace(searchTerm, '&&');
var strArray = strReplace.split(" ");
var index = strArray.indexOf('&&');
if(index != -1){
  index = index -2 >= 0 ? index -2 : index;
  var result = strArray.slice(index).join(" ").replace('&&', searchTerm);
}
console.log(result);

Answer 3

您可以使用数组spilt()，slice()和join()方法来实现：

let str = "This is example sentence for this stack overflow question";
let searchTerm =  "stack"
function getSubstring(str){
  var arrStr = str.split(' ');
  var termIndex = arrStr.indexOf(searchTerm);
  var res;
  if(termIndex-2 > -1){
    res = arrStr.slice(termIndex-2).join(' ');
  } else {
    res = arrStr.slice(termIndex).join(' ');
  }
  return res;
}
console.log(getSubstring(str));
str = "stack overflow question"
console.log(getSubstring(str));

Answer 4

执行以下操作：

const str = "This is example sentence for this stack overflow question"
const searchTerm =  "stack";
var strArray = str.split(" ");
var searchTermIndex = strArray.indexOf(searchTerm);
if(searchTermIndex-2 > -1){
var result= strArray.slice(searchTermIndex-2).join(" ");
 console.log(result);
   }

在javascript中选择关键字之前获取所有字符

4 个答案: