diff --git a/curriculum/challenges/english/blocks/lecture-working-with-strings-in-javascript/673263e80dd43da7df3ae565.md b/curriculum/challenges/english/blocks/lecture-working-with-strings-in-javascript/673263e80dd43da7df3ae565.md index 59ebd160320..9464127a0ba 100644 --- a/curriculum/challenges/english/blocks/lecture-working-with-strings-in-javascript/673263e80dd43da7df3ae565.md +++ b/curriculum/challenges/english/blocks/lecture-working-with-strings-in-javascript/673263e80dd43da7df3ae565.md @@ -5,7 +5,7 @@ challengeType: 19 dashedName: how-can-you-find-the-position-of-a-substring-in-a-string --- -# --description-- +# --interactive-- When working with strings in JavaScript, there may be times when you need to locate the position of a specific substring within a larger string. @@ -22,25 +22,35 @@ In this context, an **argument** is a value you give to a function or method whe Here is an example of using the `indexOf()` method to find the position for the string `awesome`: +:::interactive_editor + ```js let sentence = "JavaScript is awesome!"; let position = sentence.indexOf("awesome!"); console.log(position); // 14 ``` +::: + In this example, the word `awesome` starts at index `14` in the string `JavaScript is awesome!`, so the `indexOf()` method returns `14`. Now, let's see what happens when the substring isn't found: +:::interactive_editor + ```js let sentence = "JavaScript is awesome!"; let position = sentence.indexOf("fantastic"); console.log(position); // -1 ``` +::: + Since the word `fantastic` does not appear in the string, the method returns `-1`. -You can also specify where to begin searching within the string by providing a second argument to `indexOf()`. Here’s an example: +You can also specify where to begin searching within the string by providing a second argument to `indexOf()`. Here's an example: + +:::interactive_editor ```js let sentence = "JavaScript is awesome, and JavaScript is powerful!"; @@ -48,16 +58,22 @@ let position = sentence.indexOf("JavaScript", 10); console.log(position); // 27 ``` +::: + In this case, the search for `JavaScript` begins after the 10th character, and so the second occurrence of `JavaScript` is found at index `27`. It is important to note that the `indexOf()` method is case sensitive. In this example, the following would return `-1` because the capital letter `F` is not found in the string `freeCodeCamp`. +:::interactive_editor + ```js console.log("freeCodeCamp".indexOf("F")) // -1 ``` +::: + Using `indexOf()` can be very useful when you need to check if a substring is present in a string and to determine its position for further operations. # --questions--