How to use regex with numbers?

@aubrey 

To use regular expressions (regex) with numbers, you can use various patterns and special characters to match specific number sequences. Here are a few examples of how to use regex with numbers:

1. Matching a specific number pattern: You can use the d pattern to match any digit (0-9) and specify the number of digits you want to match. For example, the regex pattern d{3} will match any sequence of three digits.
2. Matching any number: To match any number (positive or negative), you can use the pattern [-+]?d+. This pattern will match any integer, including positive and negative numbers.
3. Matching decimal numbers: To match decimal numbers, you can use the pattern [-+]?d+.d+. This pattern will match any number with decimal places.
4. Matching a range of numbers: You can use the pattern [0-9] to match any digit from 0 to 9. You can also use character classes to match specific ranges of digits, such as [1-5] to match digits from 1 to 5.
5. Matching specific numbers: If you want to match specific numbers or sequences, you can use alternation (|) to match multiple patterns. For example, the pattern (123|456) will match either the number 123 or the number 456.

Overall, regex provides a powerful way to match and extract numbers from strings based on specific patterns and conditions. Depending on your requirements, you can customize these patterns to match different types of numbers with precision.