計數數組中的元素並將它們進行比較，javascript

Question

我試圖用我非常有限的Javascript知識來解決問題。

我試圖建立一種方法來計算一個特定的字母出現在一個數組中的次數，並將其與另一個字母出現在同一個數組中的次數進行比較。

我能夠通過3個4測試，並重新編寫代碼多次嘗試儘可能多的方法，我知道。

我意識到我所做的並不高效......只是努力解決問題，並花費數週的時間。

欣賞任何輸入。謝謝。

function isValidWalk(walk) { 
 
var north = new Object(); 
 
var south = new Object(); 
 
var east = new Object(); 
 
var west = new Object(); 
 
for (var i = 0; i <walk.length; i++){ 
 
if (walk[i] == "n") 
 
{north.input = "x"} 
 
} 
 
for (var i = 0; i <walk.length; i++){ 
 
if (walk[i] == "s") 
 
{south.input = "x"} 
 
} 
 
for (var i = 0; i <walk.length; i++){ 
 
if (walk[i] == "e") 
 
{east.input = "x"} 
 
} 
 
for (var i = 0; i <walk.length; i++){ 
 
if (walk[i] == "w") 
 
{west.input = "x"} 
 
} 
 

 

 

 
if (north.input == south.input && east.input == west.input && walk.length==10) { 
 
return true; 
 
} 
 
else { 
 
return false; 
 
} 
 
}

Answer 1

這裏是我會怎麼做：

function isValidWalk(walk) { 
 
    var steps = {n: 0, s: 0, e: 0, w: 0}; 
 

 
    for (var i=0, l=walk.length; i<l; i++) { 
 
     if (steps.hasOwnProperty(walk[i])) { 
 
      steps[walk[i]]++; 
 
     } else { 
 
      return false; // The element is not "n","s","e", or "w" 
 
     } 
 
    } 
 

 
    return (steps.n == steps.s && steps.e == steps.w && walk.length == 10); 
 
} 
 

 
console.log(isValidWalk(['n','n','n','s','n','s','n','s','n','s'])); // returns false 
 
console.log(isValidWalk(['n','n','n','s','s','s','n','s']));   // returns false 
 
console.log(isValidWalk(['n','gg','hh','s','s','s','n','s','n','n'])); // returns false 
 
console.log(isValidWalk(['n','n','n','s','s','s','n','s','n','s'])); // returns true