RegEx for matching "A-Z, a-z, 0-9, _" and "."

Question

I need a regex which will allow only A-Z, a-z, 0-9, the _ character, and dot (.) in the input.

I tried:

[A-Za-z0-9_.] 

But, it did not work. How can I fix it?

question from:https://stackoverflow.com/questions/1721602/regex-for-matching-a-z-a-z-0-9-and

Answer 1

^[A-Za-z0-9_.]+$

From beginning until the end of the string, match one or more of these characters.

Edit:

Note that ^ and $ match the beginning and the end of a line. When multiline is enabled, this can mean that one line matches, but not the complete string.

Use A for the beginning of the string, and z for the end.

See for example: http://msdn.microsoft.com/en-us/library/h5181w5w(v=vs.110).aspx