Question

我有一个字符串：

expect(hash).to.include('@');

如何检查此字符串是否恰好包含五个@？

我可以检查字符串是否包含一个@：

   <form class="form-inline mt-2 mt-md-0">
            <input
              class="form-control mr-sm-2"
              type="text"
              name="search"
              placeholder="Search"
              aria-label="Search"
            />
            <button id="search-btn" class="btn btn-outline-success my-2 my-sm-0" type="submit">
              Search
            </button>
  </form>

 <ul id="response">
          <li>Attack
          </li>
          <li>Defence
          </li>
          <li>Strength
          </li>
          <li>HitPoints
          </li>
 </ul>

Answer 1

您可以计算发生次数，然后验证计数：

const hash = 'dwqdiojqwoidj@2323joij@oindoi2d@dndi2on@diodno@1';
const count = (hash.match(/@/g) || []).length;
expect(count).to.equal(5);

Answer 2

let isValid = 0
for (let i = 0; i < hash.length; i++) {
    if (hash.includes("@", i)){
       isValid++;
       if(isValid === 5) {
           // do something   (true)
       }
    } else { 
       // do something   (false)
    }
}

如何通过字符串检查字符串是否包含五个@？

2 个答案: