How to use regex command to match a certain amount of characters in a field?

[showard22]

I want to use Splunk to match on a field name for accounts with exactly 4 characters, all numbers and letters.

I keep trying:

index=corp sourcetype=importantlogs | fields Account EventType | regex Account="[a-zA-Z0-9]{4}"

I feel like I'm overlooking something super simple and I've been stuck on this for a few hours. Any outsider thoughts?

[DalJeanis]

woodcock has a good answer, once you change the period to a more limited character class (\w is the simplest) For the same effect of keeping only accounts that are exactly 4 "word" characters, you could also use...

| where like(Account, "^\w{4}$"

[woodcock]

You did not anchor it; try this:

index=corp sourcetype=importantlogs | fields Account EventType | regex Account="^.{4}$"

[DalJeanis]

Need a smaller character class, only letters and numbers.

[woodcock]

A simpler match character is more efficient and worth the infinitesimally small risk of a false positive.