将值与数组进行比较

Question

我试图将值与我的数组进行比较,但是,它不能正常工作.当值为Ontario时,应将其返回为缩写为"ON",并且当在数组列表中找不到该值时,应返回与放置它时相同的值.第一个警报框返回'Ontario'？我在这做错了什么:

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

您可能希望使用地图/关联数组而不是现在拥有的数组; 这样做更容易.

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

然后你可以这样做:

return prov_states[value.toLowerCase()];

您遇到的问题是因为您在找不到值时所做的事情:

else { return value }

这意味着如果第一场比赛不成功,您立即返回value.相反,如果你根本找不到匹配,你应该这样做.

一个while循环应该工作:

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你有BC as "british Columbia",因为你正在调用value.toLowerCase()它永远不会匹配,这会降低整个字符串的范围.