Question

I'm a learning newbie.

In my code at: "https://codepen.io/JonasJsk/pen/qrzLzv"

MYAPPLICATION.DisplayNames = function ()
{
  var i, len, str;
  for(i = 0, len = MYAPPLICATION.Names.length, str = ""; i < len; ++i)
  {
    str += MYAPPLICATION.Names[i] + "<br>";
  }
  console.log(document.getElementById("content").innerHTML = str);
}

I have declared an javascript array with both strings and numbers.

1 - I'm trying to figure out how I can specifically only print-out the strings to the console.

I have been at this for hours, please help me!

Answer 1

Using your code example you can iterate over MYAPPLICATION.Names array with the method Array.prototype.forEach() and validate the typeof every element in the array is an string:

var MYAPPLICATION = MYAPPLICATION || {};
MYAPPLICATION.Names = ["Superman", "Batman", "Flash", 66, 23, 97]
MYAPPLICATION.DisplayNames = function () {
  var content = document.getElementById('content');
  var ul = document.createElement('ul');
  MYAPPLICATION.Names.forEach(function (item) {
    if (typeof item === 'string') {
      var li = document.createElement('li');
      li.appendChild(document.createTextNode(item));
      ul.appendChild(li);
    }
  });
  
  content.innerHTML = '';
  content.appendChild(ul);
}

<h2>Lab #2.1</h2>

<button type="button" onclick="MYAPPLICATION.DisplayNames()">
    Get Names
</button>

<div id="content"></div>

Answer 2

You can use the typeof operator like this :

var aList = [1, 2, 3, "one", "two", "three"];

for(var i = 0; i < aList.length; i++) {
  if(typeof(aList[i]) == "string")
  console.log("This is a string : "+aList[i]);
}

I hope this helps. :)

Answer 3

I don't understand your question... Do you want to remove the numbers from the array or you want to print the information only on the console.log ?

Anyway, try this one:

var MYAPPLICATION = MYAPPLICATION || {};

MYAPPLICATION.Names = ["Superman", "Batman", "Flash", 66, 23, 97]

MYAPPLICATION.DisplayNames = function ()
{
  //MYAPPLICATION.myJSON = JSON.stringify(MYAPPLICATION.Names);
  var i, len, str;
  for(i = 0, len = MYAPPLICATION.Names.length, str = ""; i < len; ++i)
  {
    if (!isNaN(MYAPPLICATION.Names[i])) { continue; }
    str += MYAPPLICATION.Names[i] + "<br>";
  }
  console.log(document.getElementById("content").innerHTML = str);
}

You can also remove the console.log if you don't want to print in the console.

Like:

var MYAPPLICATION = MYAPPLICATION || {};

MYAPPLICATION.Names = ["Superman", "Batman", "Flash", 66, 23, 97]

MYAPPLICATION.DisplayNames = function ()
{
  var i, len, str;
  for(i = 0, len = MYAPPLICATION.Names.length, str = ""; i < len; ++i)
  {
    name = MYAPPLICATION.Names[i]
    if (!isNaN(name)) { continue; }
    str += name + "<br>";
  }
  document.getElementById("content").innerHTML = str;
}

Answer 4

 //considering that the key is added when you have at least one incident
 if (yourHash.get("yourDateStringWhatEverTheFormatIs") != null)

Javascript array - how to print strings only

4 个答案: