javascript - 将值与数组进行比较

Question

我正在尝试将值与我的数组进行比较，但是，它没有按预期工作。当值为 Ontario 时，应返回缩写为“ON”的值；当在数组列表中未找到该值时，应返回与输入值相同的值。第一个警报框返回“安大略省”？我在这里做错了什么:

function shorten(value) {

    var prov_states = [
        ['alberta','AB'],
        ['british Columbia','BC'],
        ['manitova','MB'],
        ['new brunswick','NB'],
        ['newfoundland and labrador','NL'],
        ['nova scotia','NS'],
        ['northwest territories','NT'],
        ['new brunswick','NB'],
        ['nunavut','NU'],
        ['ontario','ON'],
        ['prince edward island','PE'],
        ['quebec','QC'],
        ['saskatchewan','SK'],
        ['yukon','YT'],
        ['alabama','AL'],    
        ['alaska','AK'],
        ['arizona','AZ'],
        ['arkansas','AR'],
        ['california','CA'],
        ['colorado','CO'],
        ['connecticut','CT'],
        ['delaware','DE'],
        ['florida','FL'],
        ['georgia','GA'],
        ['hawaii','HI'],
        ['idaho','ID'],
        ['illinois','IL'],
        ['indiana','IN'],
        ['iowa','IA'],
        ['kansas','KS'],
        ['kentucky','KY'],
        ['louisiana','LA'],
        ['maine','ME'],
        ['maryland','MD'],
        ['massachusetts','MA'],
        ['michigan','MI'],
        ['minnesota','MN'],
        ['mississippi','MS'],       
        ['missouri','MO'],
        ['montana','MT'],    
        ['nebraska','NE'],
        ['nevada','NV'],
        ['new hampshire','NH'],
        ['new jersey','NJ'],
        ['new mexico','NM'],
        ['new york','NY'],
        ['north carolina','NC'],
        ['north dakota','ND'],
        ['ohio','OH'],
        ['oklahoma','OK'],
        ['oregon','OR'],
        ['pennsylvania','PA'],
        ['rhode island','RI'],
        ['south carolina','SC'],
        ['south dakota','SD'],
        ['tennessee','TN'],
        ['texas','TX'],
        ['utah','UT'],
        ['vermont','VT'],
        ['virginia','VA'],      
        ['washington','WA'],
        ['west virginia','WV'],
        ['wisconsin','WI'],
        ['wyoming','WY']            
        ]


  for (var i=0, iLen=prov_states.length; i<iLen; i++) {

    if (value.toLowerCase() == prov_states[i][0]) { return prov_states[i][1]; }

    else { return value }

  }
}


function test() {

alert(shorten('Ontario'))

alert(shorten('DC'))


}

Answer 1

您可能想使用 map /关联数组而不是现在的数组；这样就容易多了。

var prov_states = {
    "alberta": "AB",
    "british columbia": "BC",
    ...
}

然后你可以这样做:

return prov_states[value.toLowerCase()];

您的特定问题是因为您在找不到值时所做的事情:

else { return value }

这意味着如果第一次匹配不成功，则立即返回 value 。相反，只有当您根本无法找到匹配项时才应该这样做。

一个while循环应该可以工作:

var i = 0;
var state = null;
while(state === null && i < prov_states.length) {
    if(value.toLowerCase() === prov_states[i][0]) {
        state = prov_states[i][1];
    }

    i++;
}

return state === null ? value : state; //or just return state if you are okay with null

我看到的另一个问题是您将 BC 设置为 "british Columbia" ，这永远不会匹配，因为您正在调用 value.toLowerCase() ，将整个字符串小写。