获取字符串中重复的字符数 [英] Get duplicate characters count in a string

问题描述

任何人都可以帮助我获取javascript中给定字符串中重复字符的计数.

Can anyone help me to get the count of repeated characters in a given string in javascript.

例如，

"abccdef" -> 1 (Only "c" repeated)

"Indivisibilities" -> 2 ("i" and "s" repeated)

谢谢

推荐答案

这是一个有趣的问题.我们可以做的是使用 String.toLowerCase 将字符串转换为小写，然后在" 上分割，这样我们得到了一个字符数组.

This is an interesting problem. What we can do is turn the string to lower case using String.toLowerCase, and then split on "", so we get an array of characters.

然后我们将使用 Array.sort 对它进行排序.排序后，我们将使用 Array.join 将其加入.然后，我们可以使用正则表达式/(.)\ 1 +/g ，这实际上意味着匹配一个字母和相同的后续字母.

We will then sort it with Array.sort. After it has been sorted, we will join it using Array.join. We can then make use of the regex /(.)\1+/g which essentially means match a letter and subsequent letters if it's the same.

当我们在声明的正则表达式中使用 String.match 时，我们将得到一个数组，其长度就是答案.还使用一些 try ... catch 返回 0 ，以防匹配返回 null 并导致 TypeError .

When we use String.match with the stated regex, we will get an Array, whose length is the answer. Also used some try...catch to return 0 in case match returns null and results in TypeError.

function howManyRepeated(str){
   try{ return str.toLowerCase().split("").sort().join("").match(/(.)\1+/g).length; }
   catch(e){ return 0; } // if TypeError
}
console.log(howManyRepeated("Indivisibilities")); // 2

这篇关于获取字符串中重复的字符数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！