What are ^.* and .*$ in regular expressions?

Question

Can someone explain the meaning of these characters. I've looked them up but I don't seem to get it.

The whole regular expression is:

/^.*(?=.{8,})(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]).*$/ 

So basicly the start of the regex and the end characters.

Answer 1

• . means "any character".
• * means "any number of this".
• .* therefore means an arbitrary string of arbitrary length.
• ^ indicates the beginning of the string.
• $ indicates the end of the string.

The regular expression says: There may be any number of characters between the expression (?=.{8,})(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]) and the beginning and end of the string that is searched.

Answer 2

^.* //Start of string followed by zero or more of any character (except line break)  .*$ //Zero or more of any character (except line break) followed by end of string 

So when you see this...

(?=.*[@#$%^&+=]).*$ 

It allows any character (except line break) to come between (?=.*[@#$%^&+=]) and the end of the string.

To show that . doesn't match any character, try this:

/./.test('\n');  is false 

To actually match any character you need something more like [\s\S].

/[\s\S]/.test('\n') is true