Stop gninnipS My sdroW

6 kyu

題目描述

Description

Write a function that takes in a string of one or more words, and returns the same string, but with all words that have five or more letters reversed (Just like the name of this Kata). Strings passed in will consist of only letters and spaces. Spaces will be included only when more than one word is present.

Examples:

"Hey fellow warriors"  --> "Hey wollef sroirraw"
"This is a test        --> "This is a test"
"This is another test" --> "This is rehtona test"

解答

Solution

function spinWords(string) {
  const stringArr = string.split(" ");
  const result = [];

  for (let string of stringArr) {
    if (string.length >= 5) {
      result.push(string.split("").reverse().join(""));
    } else {
      result.push(string);
    }
  }

  return result.join(" ");
}

解題思路

如果字串長度大於等於 5,使用 split('').reverse().join('') 將字串反轉，反之維持不變。

split('').reverse().join('') 的步驟拆解如下:

const word = "範例字串"
const wordSplit = word.split(""); //令輸入的字串轉為陣列
const reverseArray = wordSplit.reverse(); //反轉輸入的陣列
const joinArray = reverseArray.join(""); //連接反轉的陣列
console.log(joinArray); // "串字例範"

也可以使用展開運算子

const word = "範例字串";
const reversed = [...word].reverse().join("");
console.log(reversed); // "串字例範"

或是使用迴圈反轉

const word = "範例字串";
let reversed = "";
for (let char of word) {
  reversed = char + reversed; // 每次把字加到前面
}
console.log(reversed); // "串字例範"

心得

練習如何在 JavaScript 中將字串反轉。