Question

所以代码学院说我正确地完成了这个但它没有产生任何结果。它应该精确定义“Alex”名称出现在var文本中的次数。有人可以告诉我我做错了吗？

注意：此当前代码的结果只是= []

提前谢谢，这是代码：

var text = "Alex, blah, Alex, blah, blah, blah, Alex, blah, Alex"

var myName = "Alex"
var hits = []

for (var i=0; i<text.length; i++){
    if (text[i] === "A"){
        for (var j = i; j < i + myName.length;j++){
            hits.push(j);
        }
    }
}

if (hits.length = 0){
    console.log("Your name wasn't found")
}
else{
    console.log(hits);
}

Answer 1

如果你被允许使用正则表达式，这很简单......

＆＃13;

var text = "Alex, blah, Alex, blah, blah, blah, Alex, blah, Alex"

var myName = "Alex"
var hits = []

hits = text.match(new RegExp( "\\b"+myName+"\\b", "g"));

if (hits.length == 0){
    console.log("Your name wasn't found")
}
else{
    console.log(hits);
}

＆＃13;

Answer 2

问题在这里：

hits.push(j); // you push index not symbol

应该是：

 hits.push(text[j]);

我的解决方案：

var text = "af grwg rh thrthj jjy jtj Denys g er Denys";
var myName = "Denys";
var hits = [];
var k = 0;

for (var i = 0; i < text.length; i++){
    if (text[i] === "D"){
        for(var j = i; j < myName.length + i; j++){
            hits.push(text[j]);
        }
        ++k;
    }    
}
if (hits === []){
    console.log("Your name wasn't found!");
}
else{
    console.log("Your name was found " + k + " times!");
}

我也想问你：你知道https://discuss.codecademy.com吗？

我认为你可以更快地找到答案。但这是你的选择。

Answer 3

顺便提一下，有一个简洁的数组方法叫做＆＃34; reduce＆＃34;接受一个数组并返回一个值。您可以使用String的拆分方法将文本转换为数组。

＆＃13;

var text = "Alex, blah, Alex, blah, blah, blah, Alex, blah, Alex";
var textArray = text.split(', ');    // split into an array
var myName = "Alex";

// reduce the array to a single value.
// Just increase a counter each time the name matches.

var total = textArray.reduce(function(prev, curr) {
  if (curr === myName) ++prev;
  return prev;
}, 0);
console.log(total);

// or if you want to get small.
// "Variables? Variables? We don't need no stinking' variables!"

console.log("Alex, blah, Alex, blah, blah, blah, Alex, blah, Alex".split(', ').reduce(function(prev, curr) {
  return curr === "Alex" ? ++prev : prev;
}, 0));

＆＃13;

CodeAcademy;程序不适用于JS

3 个答案: