I'm going to go off and read a book on regex now (and watch some videos), as they have finally "clicked" for me and I now have that seed which is spurring me on to learn more. There's probably much better ways to do this, but this is the result of my exploration so far. $Input -match "^#$%^()\\-')įair enough, that may still look a little complex if you're new to regex but I hope that having built it up step by step it can be deciphered.Īlso, if you're a regex guru be gentle. I would then blindly drop that into my script. I'd head off to Google and search for " NetBIOS name regex" and likely end up grabbing something from the first Stack Overflow result.
The best I'd managed in the past was to Google a pattern that matched what I was looking for and stole re-purposed them in my scripts without much understanding of how or why it actually worked.įor example, let's say I was trying to ensure that input was a valid NetBIOS name.
I've seen these expressions used by (scripting) wizard to do amazing things, but I have never been able to wrap my head around them.
REGEX FOR NUMBER HOW TO
Regex for Numbers and Number Range at Ī tutorial that teaches you how to match numbers and number range in Regular expressions.For the longest time, Regex has been similar to black magic in my mind. It explains them in an easy-to-read format with good examples. Numeric Ranges in Ī great resource of information about regular expression number ranges. It is a function that takes two integers: the min value and max value (formatted as strings or numbers) and returns a valid regular expression.
REGEX FOR NUMBER GENERATOR
This Regex Numeric Range Generator is built with JavaScript using an open source to-regex-range package. The three digit numbers need to be split futher into 100-199 ("1" or in short "1|2|25)". Now our single digit numbers are 0-9, two digit numbers are 10-99 (""), but three digit numbers are 100-255. Example: Regex Number Range 0-255Īgain we have one, two and three digit numbers. Again we can join these with the alternation operator to get "(||100)". And there's only one three digit number "100". So it's similar to 1-20, but now our two digit numbers are 10-99 (or in regex: ""). Range 1-100 has one, two and three digit numbers. Then we can join all these with an alternation operator to get "(|1|20)". For double digit numbers we have to split the group in two 10-19 (or in regex: "1") and 20. Range 1-20 has both single digit numbers (1-9) and two digit numbers (10-20). 3-9 OR 1) Example: Regex Number Range 1-20 The final regex simply combines these two with the alternation operator (|) resulting in '(3-9|1)' (i.e. The first digit is 1 and the second digit 0-3. Group a) has a single digit and can be matched simply with regex '', while group b) can has two digits. for range 3-13 you can have two groups a) 3-9 and b) 10-13. The easies way to do this is to start by splitting the range based on how many digits each number has.Į.g. In order to match a multi-digit numeric ranges in regex, you need to approach the problem by splitting it into smaller chunks. ), it can be replaced with a shorthand (\d). A Note about Matching Numbers (Hint: Its harder than you think) Matching a number is one of those things youd think is quite easy with regex, but its actually pretty tricky. If the character group allows any digit (i.e. Note that this doesnt work in every case, like newline (n), open square bracket () and backslash ( or ). Or you can match a range of digits with a character group e.g. You can use a number from 0 to 9 to match a single choice. With regex you have a couple of options to match a digit. You need to use regex in Google Analytics for example in order to filter numeric values in custom dimensions. There might be also products such as Google Analytics that format custom data values as strings. So why not just convert a string to int before comparison? In some cases you need to find numbers inside strings and regular expression is often an option that performs well. Instead regex goes through the string character by character and checks if it matches the pattern.
In other words, a regex doesn't know that 1-10 means any number from 1 to 10. The challenge is that regex doesn't know what a number is. Regular expressions are patterns used to match character combinations in strings.
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