I'm trying to find the first character in an Array in JavaScript.

I have this a random function (not the best, but I am going to improve it):

function random() {
var Rand = Math.floor(Math.random()*myArray.length);
document.getElementById('tr').innerHTML = myArray[Rand];
}

And here's my Array list.

myArray = ["where", "to", "get", "under", "over", "why"];

If the user only wants arrays with W's, only words with a W in the first letter is shown. (Like "where" or "why")

I do not have a lot of experience with JavaScript from before and I have been sitting with this problem for ages.

I'm trying to find the first character in an Array in JavaScript.

I have this a random function (not the best, but I am going to improve it):

function random() {
var Rand = Math.floor(Math.random()*myArray.length);
document.getElementById('tr').innerHTML = myArray[Rand];
}

And here's my Array list.

myArray = ["where", "to", "get", "under", "over", "why"];

If the user only wants arrays with W's, only words with a W in the first letter is shown. (Like "where" or "why")

I do not have a lot of experience with JavaScript from before and I have been sitting with this problem for ages.

• javascript
• arrays
• math
• search
• random

2 Answers 2

There's indexOf() method of an array/string which can provide you with a position of a letter. First letter has a position of 0(zero), so

function filter(letter) {
  var results = [];
  var len = myArray.length;
  for (var i = 0; i < len; i++) {
    if (myArray[i].indexOf(letter) == 0) results.push(myArray[i]);
  }
  return results;
}

Here is a jsFiddle for it. Before running open the console(Chrome: ctrl+shift+i, or console in FireBug) to see resulting arrays.

You can filter the array to contain only specific values, such as the ones starting with 'w'

var words = ["where", "to", "get", "under", "over", "why"];
var wordsWithW = words.filter(function(word) {
  return word[0] == 'w';
});
var randomWordWithW = wordsWithW[Math.floor(Math.random() * wordsWithW.length];
... // operate on the filtered array afterwards

If you plan to support the aged browsers you might want to consider using underscore.js or Prototype

When using underscore you could simply write this:

var randomWordWithW = _.chain(words).filter(function(word) {
  return word[0] == 'w';
}).shuffle().first().value()