题解 | #统计字符#正则表达式解法

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    let str = await readline()
    let letter = 0,
        space = 0,
        num = 0,
        other = 0
    for (let i=0; i<str.length; i++) {
        let word = str[i]
        if (/[a-z]/ig.test(word)) {
           letter ++ 
        } else if (/\s/.test(word)) {
            space ++
        } else if (/[0-9]/.test(word)) {
            num ++
        } else {
            other ++
        }
    }
    console.log(`${letter}\n${space}\n${num}\n${other}`)
}()