一般的和简单的:

function betweenMarkers(text, begin, end) { var firstChar = text.indexOf(begin) + begin.length; var lastChar = text.indexOf(end); var newText =文本。substring (firstChar lastChar); 返回newText; ｝ console.log (betweenMarkers(“MyLongString: StringIWant ;",":",";"));

下面是一个可重用的函数，它允许你使返回的子字符串包含或排除，然后可选地修剪它:

function get_substring(full_string, substring_1, substring_2, inclusive, trim)
{
    if (full_string === null) { return null; };
    let substring_1_start = full_string.indexOf(substring_1);
    if (substring_1_start === -1 ) { return null; }
    let substring_2_start = full_string.indexOf(substring_2, substring_1_start);
    if (substring_2_start === -1 ) { return null; }
    let substring_1_end = substring_1_start + substring_1.length;
    let substring_2_end = substring_2_start + substring_2.length;
    let return_string = inclusive ? (full_string.substring(substring_1_start, substring_2_end)) : (full_string.substring(substring_1_end, substring_2_start));
    return trim ? return_string.trim() : return_string;
}

使用例子:

//Returns 'cake and ice cream'
get_substring('I like cake and ice cream', 'cake', 'cream', true, true);

//Returns ' and ice '
get_substring('I like cake and ice cream', 'cake', 'cream', false, false);

//Returns 'and ice'
get_substring('I like cake and ice cream', 'cake', 'cream', false, true);

//Returns null
get_substring('I like cake and ice cream', 'cake', 'cookies', false, false);

//Returns null
get_substring('I like cake and ice cream', null, 'cream', false, false);

我做的一个小函数，可以抓取之间的字符串，并且可以(可选地)跳过一些匹配的单词来抓取特定的索引。

同样，将start设置为false将使用字符串的开头，将end设置为false将使用字符串的结尾。

将pos1设置为您想要使用的开始文本的位置，1将使用start的第一次出现

Pos2和pos1做同样的事情，但是对于end，并且1将只在start之后使用end的第一次出现，在start之前出现的end将被忽略。

function getStringBetween(str, start=false, end=false, pos1=1, pos2=1){
  var newPos1 = 0;
  var newPos2 = str.length;

  if(start){
    var loops = pos1;
    var i = 0;
    while(loops > 0){
      if(i > str.length){
        break;
      }else if(str[i] == start[0]){
        var found = 0;
        for(var p = 0; p < start.length; p++){
          if(str[i+p] == start[p]){
            found++;
          }
        }
        if(found >= start.length){
          newPos1 = i + start.length;
          loops--;
        }
      }
      i++;
    }
  }

  if(end){
    var loops = pos2;
    var i = newPos1;
    while(loops > 0){
      if(i > str.length){
        break;
      }else if(str[i] == end[0]){
        var found = 0;
        for(var p = 0; p < end.length; p++){
          if(str[i+p] == end[p]){
            found++;
          }
        }
        if(found >= end.length){
          newPos2 = i;
          loops--;
        }
      }
      i++;
    }
  }

  var result = '';
  for(var i = newPos1; i < newPos2; i++){
    result += str[i];
  }
  return result;
}

这是我刚做的东西。

注意，如果在启动后没有找到end，函数将返回启动后的所有内容。它还期望只有一次出现的开始和结束，如果有多次，它将只考虑第一次。

许可:公共领域

/**
 * Extracts a string from `source` that is placed between `start` and `end`. The function
 * considers only one instance of start and before, or the first instance and does not support
 * multiple occurences otherwise. If end string is not found, it will return everything after
 * `start` to the end of the string.
 */
export function stringBetween(source, start, end) {
  if (source.indexOf(start) === -1) {
    return null;
  }

  const sourceSplitByStartString = source.split(start);

  // Note: If start string is the very first occurence in source string, the result will be an
  // array where the first item is an empty string and the next item is of interest.

  if (
    sourceSplitByStartString.length === 1
    || sourceSplitByStartString[1] === ''
  ) {
    // It means that start is either the entire string or is at the very end of the string, so there
    // is not anything between
    return '';
  }

  const afterStart = sourceSplitByStartString[1];

  // If the after separator is not found, return everything after the start separator to the end
  // of the string
  if (afterStart.indexOf(end) === -1) {
    return afterStart;
  }

  const afterStartSplitByEnd = afterStart.split(end);

  if (afterStartSplitByEnd[0] === '') {
    return '';
  }

  return afterStartSplitByEnd[0];
}

测试:

import { stringBetween } from './string';

describe('string utlities', () => {
  describe('stringBetween', () => {
    it('Extracts a substring between 2 other substrings', () => {
      const sample1 = stringBetween('Black cat climbed the tree fast.', 'cat ', ' the tree');
      expect(sample1).toBe('climbed');

      const sample2 = stringBetween('Black cat climbed the tree fast.', 'Black ', ' fast.');
      expect(sample2).toBe('cat climbed the tree');
    });

    it('extracts everything after start if end is not found', () => {
      const sample2 = stringBetween('Black cat climbed the tree fast.', 'Black ', 'not-there');
      expect(sample2).toBe('cat climbed the tree fast.');
    });

    it('returns empty string if start string occurs at the end', () => {
      const sample = stringBetween('Black cat climbed the tree fast.', 'fast.', 'climbed');
      expect(sample).toBe('');
    });

    it('returns empty string if start string is the entire string', () => {
      const sample = stringBetween('Black cat', 'Black cat', 'climbed');
      expect(sample).toBe('');
    });

    it('returns empty string if there is not anything between start and end', () => {
      const sample = stringBetween('Black cat climbed the tree fast.', 'climbed ', 'the tree');
      expect(sample).toBe('');
    });

    it('returns null if start string does not exist in the source string', () => {
      const sample = stringBetween('Black cat climbed the tree fast.', 'not-there ', 'the tree');
      expect(sample).toBe(null);
    });
  });
});

使用' get_between '实用函数:

get_between <- function(str, first_character, last_character) {
    new_str = str.match(first_character + "(.*)" + last_character)[1].trim()
    return(new_str)
    }

字符串

my_string = 'and the thing that ! on the @ with the ^^ goes now' 

用法:

get_between(my_string, 'that', 'now')

结果:

"! on the @ with the ^^ goes

下面的函数获取第一个匹配项

function getStringBetween(x: string, start: string, end: string) {
  const regex = new RegExp(`${start}(.*?)${end}`)

  if (regex.test(x)) {
    return regex.exec(x)![1]
  } else return undefined
}

有测试

test("getStringBetween", () => {
  const result = getStringBetween("<em> Jai Ram</em>", "<em>", "</em>")
  expect(result).toEqual(" Jai Ram")
  const result1 = getStringBetween(
    "hare Jai Ram hare hare hare",
    "hare",
    "hare"
  )
  expect(result1).toEqual(" Jai Ram ")
})