If / Else语句大括号

debugcn 发表于 Dev

新鲁道夫

我试图用两个参数创建一个函数，一个用于数组（ary），第二个用于在数组内搜索的名称。

但是，我不明白为什么第一个代码不起作用而第二个代码却不起作用。

有人可以解释一下吗？

// wrong code
var fruit = ['banana', 'apple', 'cherry', 'watermelon'];
var food = ['pizza', 'rice', 'cheese', 'potato'];
var search = function(ary, name) {
    for (var i = 0; i < ary.length; i++) {
        if (name == ary[i]) {
            return name + " was found!";
        } else {
            return name + " was not found";
        }
    }
};
search(food, 'potato');
//"potato was not found"


// right code
var fruit = ['banana', 'apple', 'cherry', 'watermelon'];
var food = ['pizza', 'rice', 'cheese', 'potato'];
var search = function(ary, name) {
    for (var i = 0; i < ary.length; i++)
        if (name == ary[i]) 
            return name + " was found!";
    return name + " was not found";
};

search(food, 'potato');
//"potato was found!"

谢谢！

易卜拉欣·马尔里尔

for (var i = 0; i < ary.length; i++)
    if (name == ary[i]) 
        return name + " was found!";
return name + " was not found";

是相同的：

for (var i = 0; i < ary.length; i++) {
    if (name == ary[i]) {
        return name + " was found!";
    }
}
return name + " was not found";

它false遍历数组中的所有项目后返回。在您提供的错误代码中，它仅检查第一项是否等于，name因为在循环内，无论是否找到name它，您都将返回（因此，如果第一项等于它，则将返回true；如果未找到，则将返回false）因此，1将不会检查来自索引的项目，因为该函数已经返回。

注意：您可以在JS中使用默认的搜索功能indexOf：

var search = function(ary, name) {
    if(ary.indexOf(name) != -1) // index is -1 (not valid) then it's not found
        return name + " was found";
    else
        return name + " was not found";
}

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