RegEx - use of carat

#1

Can someone confirm my understanding of the different uses for ^ please.

/[^aeiou]/

  • This checks if string contains anything EXCEPT a, e, i, o, u.

/^[aeiou]/

  • This checks if string contains anything EXCEPT “aeiou”.

/^aeiou/

  • This checks if string BEGINS with “aeiou”.

Thanks.

#2

Here’s a post taken from stackOverflow

^ only means “not the following” when inside and at the start of [], so [^...].

When it’s inside [] but not at the start, it means the actual ^ character.

When it’s escaped (\^), it also means the actual ^ character.

In all other cases it means start of the string / line (which one is language / setting dependent).

So in short:

[^abc] -> not a, b or c
[ab^cd] -> a, b, ^ (character), c or d
\^ -> a ^ character

Anywhere else -> start of string / line.
So ^[b-d]t$ means:

Start of line
b/c/d character
t character
End of line

#3