SS+=+'IiFe+s+hort,+i+use+PYtHon'+定义一个函数统计字符串i或I出现的次数

以下是统计字符串中i或I出现次数的函数：

function countI(str) {
  let count = 0;
  for (let i = 0; i < str.length; i++) {
    if (str[i] === 'i' || str[i] === 'I') {
      count++;
    }
  }
  return count;
}

let SS = 'IiFe+s+hort,+i+use+PYtHon';
console.log(countI(SS)); // 输出：5