如何计算JavaScript中字符串中特定字符串的出现次数
我们需要编写一个包含两个字符串的JavaScript函数，例如str1和str2。然后，该函数应计数并返回str2在str1'中出现的次数
例如-
count('this is a string', 'is') should return 2;示例
为此的代码将是-
const str1 = 'this is a string';
const str2 = 'is';
const countOccurrences = (str1, str2, allowOverlapping = true) => {
str1 += "";
str2 += "";
if (str2.length <= 0) return (str1.length + 1);
var n = 0,
pos = 0,
step = allowOverlapping ? 1 : str2.length;
while (true) {
pos = str1.indexOf(str2, pos);
if (pos >= 0) {
++n;
pos += step;
} else break;
}
return n;
};
console.log(countOccurrences(str1, str2));输出结果
控制台中的输出将是-
2