我需要在函式中回傳一個包含所有匹配天數的字串，但我不理解我需要正確執行此操作的基本原則。我想將天數映射到一天 IE "0" = "Monday"（在這種情況下只是 MF）；我相信 .map 是我想要的，但我還不夠了解。
function dayOfWeek(dayIndex) {
return ["Monday","Tuesday","Wednesday","Thursday","Friday"][dayIndex] || '';
}
const days = [1,2,3,4,5];
console.log(dayOfWeek(days));僅回傳“星期一”，即第一天。我希望它回傳“周一、周二、周三、周四、周五”
uj5u.com熱心網友回復：
您可以創建一個物件，為一周中的每一天數字定義一個字串值。接下來，您需要遍歷陣列并將數值轉換為字串值。
function dayOfWeek(dayIndex) {
const days = {
1: "Monday",
2: "Tuesday",
3: "Wednesday",
4: "Thursday",
5: "Friday",
6: "Saturday",
7: "Sunday"
};
return dayIndex.map((number) => days[number]);
}
如果您想使用陣列解決方案而不是物件，那么您需要從數字中減去 1（因為陣列索引以 0 開頭，而您的星期幾以 1 開頭）
function dayOfWeek(dayIndex) {
const days = [
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday",
"Sunday"
];
return dayIndex.map((number) => days[number - 1]);
}
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標籤：javascript 数组