获取两个子字符串之间的字符串(包含多于1个字符)

function substrInBetween(whole_str, str1, str2){
   if (whole_str.indexOf(str1) === -1 || whole_str.indexOf(str2) === -1) {
       return undefined; // or ""
  }
  var strlength1 = str1.length;
  return whole_str.substring(
                whole_str.indexOf(str1) + strlength1, 
                whole_str.indexOf(str2)
               );

   }

注意，我使用indexOf()而不是lastIndexOf()，因此它将检查这些字符串的第一次出现

你也可以试试这个:

var str = 'one:two;three';    
str.split(':').pop().split(';')[0]; // returns 'two'

var s = 'MyLongString:StringIWant;';
/:([^;]+);/.exec(s)[1]; // StringIWant

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 ")
})

上面的代码适用于简单的例子，但可以帮助… 使用打印稿。

参数

句子:你想要得到部分的字符串 第一个:开头字符(对于初始示例，它将是:) 最后:你的部分的最后一个字符(对于初始示例，它将是;)

输出

字符串数组(string[])。如果句子中没有好的部分，则返回[]。

Code

function getParts(sentence: string, first: string, last: string): string[] { 
  let goodParts: string[] = [];
  
  const allParts = sentence.split(first);

  allParts.forEach((part: string) => {
    if (part.indexOf(last) > -1) {
            const goodOne = (part.split(last))[0];
      goodParts = goodParts.concat(goodOne);
    }
  });
  
  return goodParts;
}

例子

const origin = "wrongString1:rightString1;wrongString2:rightString2;wrongString3:rightString3;wrongString4:rightString4;";

const result = getParts(origin, ':', ';');

console.log(result);
// ["rightString1", "rightString2", "rightString3", "rightString4"]

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);