如何计算特定字符串在另一个字符串中出现的次数。例如,这就是我试图在Javascript中做的事情:

var temp = "This is a string.";
alert(temp.count("is")); //should output '2'

当前回答

函数countInstance(字符串,单词){返回字符串.split(word).length-1;}console.log(countInstance(“This is a string”,“is”))

其他回答

看到这篇帖子。

let str = 'As sly as a fox, as strong as an ox';

let target = 'as'; // let's look for it

let pos = 0;
while (true) {
  let foundPos = str.indexOf(target, pos);
  if (foundPos == -1) break;

  alert( `Found at ${foundPos}` );
  pos = foundPos + 1; // continue the search from the next position
}

相同的算法可以被布置得更短:

let str = "As sly as a fox, as strong as an ox";
let target = "as";

let pos = -1;
while ((pos = str.indexOf(target, pos + 1)) != -1) {
  alert( pos );
}

试试看:

function countString(str, search){
    var count=0;
    var index=str.indexOf(search);
    while(index!=-1){
        count++;
        index=str.indexOf(search,index+1);
    }
    return count;
}

你可以试试这个:

var theString=“这是一个字符串。”;console.log(String.split(“is”).length-1);

添加了此优化:

如何计算字符串中的字符串出现次数?

这可能是这里最快的实现,但如果您将“++pos”替换为“pos+=searchFor.length”,则会更快汉森里克

function occurrences(str_, subStr) {
  let occurence_count = 0
  let pos = -subStr.length
  while ((pos = str_.indexOf(subStr, pos + subStr.length)) > -1) {
    occurence_count++
  }
  return occurence_count
}

String.prototype.Count=函数(查找){返回this.split(find).length-1;}console.log(“这是一个字符串。”.Count(“是”));

这将返回2。