How do I perform a match on a field ONLY on letters that are followed by numbers?

[jsven7]

Suppose I have a field like this: a1234

Is there a way to grab all the letters that are immediately followed by numbers? I know I can substr the first position but I want be able to work with this for example too: abc1234.

Ty in advance

[richgalloway · Accepted solution]

I'm not clear about what you want to accomplish, but I think the rex command will do what you want. This command will extract the letters from a field containing letters followed by numbers and put them in a field called 'letters'.

... | rex field=foo "(?<letters>[a-zA-Z]+)\d+" | ...

[jsven7]

Thank you for this. What if I want to specify letters or a combination of letters and numbers that follow numbers?

[richgalloway]

For letters that follow numbers:

"(?<foo>\d+)[a-zA-Z]+"

For letters and number following numbers:

"(?<foo>\d+)[a-zA-Z0-9]+"

regex101.com is a great site for experimenting with regular expressions.

[jsven7]

This is really helpful ty!

[acharlieh]

Then you modify the bracket expression: [a-zA-Z] which currently says "Match a single character that is either a to z, or A to Z" For example if you wanted only to match one of the lower case versions of the letters that Vanna White gives you for free in the bonus round: [rstlne] (The plus sign after this expression says instead of just one, I want one or more, as many times as I can up front)

There is a lot of nuances to crafting regular expressions for example, if a digit is one of the characters you want to match and also ensure is following... depending on requirements may not be possible, or may involve lookahead and lookbehind expressions, I would recommend taking some of your example data and playing with a online tester such as https://regex101.com/ or if you want some practice at building regular expressions play some regex golf: http://regex.alf.nu/