javascript-在數組中查找字符串

Question

在通常的“在數組中查找字符串”問題上稍作改動：

我目前知道如何使用for循環和if語句在數組中查找字符串。 但是我想做的是返回一個選項，如果遍歷整個數組后找不到匹配的字符串。 明顯的問題是，如果我在當前的if語句中包含else選項，則沒有匹配項的每次迭代都會移至else。

所以基本上，我想掃描整個陣列。 我該怎么做呢？ 謝謝（超級新手在這里：））。

var guestList = [
"MANDY",
"JEMMA",
"DAVE",
"BOB",
"SARAH",
"MIKE",
"SUZY"
];

var guestName = prompt("Hello, welcome to The Club. What is your name?").toUpperCase();

for (var i=0; i<guestList.length; i++){
    if (guestName === guestList[i]){
        alert("Hi " + guestName + " You are on the list! Enjoy The Club");
    }
}

Answer 1

無需for循環

 if(guestList.indexOf(guestName) === -1) return "xyz" else return "abc" 

Answer 2

如果仍要打印來賓名稱，則可以提供一個默認的來賓名稱，然后在for循環中可以更改或不更改它：

    var guestName = prompt("Hello, welcome to The Club. What is your name?").toUpperCase();
    var member = "GUEST";
    for (var i=0; i < guestList.length; i++) {
        if (guestName === guestList[i]){
            member = guestName;
            break;
        }
    }
    alert("Hi " + member);

或使用jQuery而沒有for循環：

var member = "GUEST";
if ($.inArray(guestName, guestList) > -1) {
    member = guestName;
}
alert("Hi " + member);

請參閱jquery inArray的文檔：

http://api.jquery.com/jquery.inarray/

Answer 3

試試這個代碼：

 var guestList = [ "MANDY", "JEMMA", "DAVE", "BOB", "SARAH", "MIKE", "SUZY" ]; var guestName = prompt("Hello, welcome to The Club. What is your name?").toUpperCase(); var greet = "xyz";//put the default text here for (var i = 0; i < guestList.length; i++) { if (guestName === guestList[i]) { greet = "Hi " + guestName + " You are on the list! Enjoy The Club"; break;//match found, stop loop } } alert(greet);//greetings here