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JavaScript JavaScript Foundations Strings Methods

Posted by layeesolo
layeesolo
7,316 Points

Help Me Please

I am stuck on question three. I don't under substr method. I have tried still can't get it right. the question is update the variable of 'wordBrown' on about line 21, to extract the substring of "brown" from the string 'quick'.

index.html 
<!DOCTYPE html>
<html lang="en">
  <head>
    <title> JavaScript Foundations: Strings</title>
    <style>
      html {
        background: #FAFAFA;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <h1>JavaScript Foundations</h1>
    <h2>Strings: Methods</h2>
    <script>
      var quick = "The quick brown fox jumps over the lazy dog";

          var quickLength    = quick.length;
          var indexOfBrown = quick.indexOf('brown');
          var tenthCharacter = quick.charAt(3);
          var wordBrown = quick.substr(2);
          var quickUpper = quick;
          var quickLower = quick;
    </script>
  </body>
</html>
Vince Brown
Vince Brown
16,249 Points
Vince Brown
Vince Brown
16,249 Points

Hey layeesolo, The .substr() method takes 2 parameters in this case the first parameter would be the point to start extracting from and the second is the length of the extraction.

So if you were trying to update wordBrown to be "brown" by extracting "brown" from var quick it would be

var wordBrown = quick.substr(10,5);

Since js index starts at 0 the extraction would start at the 10th position and since "brown" is 5 letters long the second parameter would be 5.

I hope that clears things up for you.

Cheers, Vince

2 Answers

Marcus Parsons
Marcus Parsons
15,719 Points

Use the substr(index, length) method to extract brown from quick. What you must do is start at the very beginning of the string of quick which is index 0. We count every character including spaces so "T" is 0, "h" is 1, etc. until we count up to the b in "brown" which is index 10. So, index 10 is where we start. We want to extract "brown" which is 5 characters long so we use 5 for our length. Thus:

var wordBrown = quick.substr(10,5);

<!DOCTYPE html>
<html lang="en">
  <head>
    <title> JavaScript Foundations: Strings</title>
    <style>
      html {
        background: #FAFAFA;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <h1>JavaScript Foundations</h1>
    <h2>Strings: Methods</h2>
    <script>
      var quick = "The quick brown fox jumps over the lazy dog";

          var quickLength    = quick.length;
          var indexOfBrown = quick.indexOf('brown');
          var tenthCharacter = quick.charAt(3);
          var wordBrown = quick.substr(10,5);
          var quickUpper = quick;
          var quickLower = quick;
    </script>
  </body>
</html>
Marcus Parsons
Marcus Parsons
15,719 Points

If we wanted to extract the beginning "The" from the quick string, we would start at index 0 because it has the "T" and go 3 length because "The" is 3 characters long.

var wordThe = quick.substr(0,3);
layeesolo
layeesolo
7,316 Points
layeesolo
layeesolo
7,316 Points

thanks. I understand it now.

Marcus Parsons
Marcus Parsons
15,719 Points

If you feel my answer is worthy of being the best answer, you can mark my answer as Best Answer. Thanks, layeesolo!