Скачать или смотреть Extracting a number from a string in JavaScript

Learn how to extract numeric values from strings in JavaScript using simple techniques, including string splitting and character checking.
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This video is based on the question https://stackoverflow.com/q/73157344/ asked by the user 'zippax' ( https://stackoverflow.com/u/4499844/ ) and on the answer https://stackoverflow.com/a/73157434/ provided by the user 'IT goldman' ( https://stackoverflow.com/u/3807365/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Extracting a Number from a String in JavaScript: A Step-by-Step Guide

When working with strings in JavaScript, you may come across situations where you need to extract specific information, like numeric values. In this post, we will tackle a common problem: how to effectively retrieve the number 20.0 from the string Icecream, Milk, vanilla syrup, ice cubes20.0 SR180 calories.

Understanding the Problem

In our example, the goal is to extract the number that appears right before the symbol SR. The string is structured in such a way that we can use it to our advantage when writing our solution.

You might have started by attempting to convert the string into an array and trying to find the occurrence of SR, but encountered difficulties with an index value of -1. Don’t worry, we’ve got a better approach for you!

Solution Overview

To extract the desired value, we can utilize a combination of string manipulation methods. The approach involves:

Splitting the string at the SR marker.

Reversing the characters of the first segment.

Extracting numeric characters until we encounter a non-numeric character.

Finally, assembling the reversed characters back into a string.

Step-by-Step Breakdown

Let’s implement this solution in a detailed manner:

Split the String on 'SR':
We will split the string into two parts using SR as the delimiter.

[[See Video to Reveal this Text or Code Snippet]]

Trim White Spaces and Reverse Characters:
Focus on the first part (before SR), trimming any unnecessary spaces and reverse the order of characters to easily check for numbers.

[[See Video to Reveal this Text or Code Snippet]]

Extract Numeric Characters:
Use a loop to check each character. If the character is a digit or a period, keep it. Otherwise, stop the loop.

[[See Video to Reveal this Text or Code Snippet]]

Join the Characters and Reverse:
Finally, reverse the array of numeric characters back to their original order and join them to get the final number.

[[See Video to Reveal this Text or Code Snippet]]

Complete Code Example

Here is the complete solution in one snippet:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Extracting numbers from strings in JavaScript can be accomplished efficiently through string manipulation techniques. By utilizing the steps outlined above, you can reliably extract any numeric value from formatted strings. This approach is especially useful in scenarios where data is extracted from user input or external files.

If you encounter similar challenges or have any further questions, feel free to reach out. Happy coding!