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Q:

PHP regular expression - filter number only

Hi everyone,

I'm currently working on a project where I need to extract only the numbers from a given string using PHP. I have been trying to figure out a way to filter out everything except the numbers in the string using regular expressions, but I'm having some trouble.

Here's an example of what I'm trying to achieve: let's say I have a string like "I have 3 cats and 2 dogs". I would like to extract only the numbers from this string, so in this case, the output I'm looking for is "3" and "2".

I have been searching online for a solution and came across regular expressions, but I'm not very familiar with them. Can someone please provide me with an example of how I can use regular expressions in PHP to filter out everything except the numbers in a string?

I would really appreciate any help or guidance you can provide. Thank you in advance!

All Replies

lulu64

Hey there!

I had a similar requirement in one of my projects recently, and I used regular expressions in PHP to filter out only the numbers from a string. Here's the approach that worked for me:

php
$string = "I have 3 cats and 2 dogs";
$numbers = preg_replace('/[^0-9]/', '', $string);
echo $numbers;


In the above example, I used the `preg_replace()` function with a regular expression pattern `/[^0-9]/` to match any character that is not a digit (0-9) and replace it with an empty string. This effectively removes all non-numeric characters from the string, leaving only the numbers behind.

When you run the above code, the output will be "32" which is what you were looking for. You can modify the regular expression pattern according to your specific requirements.

I hope this helps! Let me know if you have any further questions.

jpacocha

Hey there,

I encountered a similar situation where I needed to filter out numbers from a string in PHP, and I found a slightly different approach that worked for me. I hope it helps you too!

Instead of using regular expressions, I used the `filter_var()` function in combination with `FILTER_SANITIZE_NUMBER_INT` filter flag. Here's an example:

php
$string = "I have 3 cats and 2 dogs";
$numbers = filter_var($string, FILTER_SANITIZE_NUMBER_INT);
echo $numbers;


In this approach, the `FILTER_SANITIZE_NUMBER_INT` flag sanitizes the string by removing all characters except digits (0-9), effectively extracting only the numbers from the string. When you run the above code, the output will be "32", which is exactly what you need.

I found this method to be quite straightforward and concise. Give it a try and let me know if it works for you. If you have any further questions, feel free to ask!

Best of luck with your project!

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