Hi all ..
I'm quite new to Regex'es, so I was wondering if this is possible?
Take a string and check that all characters are A-Z or a-z.
My best guess so far is:
"^[A-Za-z]*$"
But it seems to have some trouble if a character in the middle of the string is not a valid character (fx. "aaa__aa"). The Regex.IsMatch returns true.. :(
[EDIT] A few comments on your answer rather than only a regex would be great :)
What you are currely saying is
The string is only valid if it contains the characters between 0 - 9 or nothing
To check if the characters are a-z or A-Z you need to used
^[A-Za-z]*$
Which says
The string is only valid if the characters are between a - z or A - Z (inclusive) or nothing
EDIT
The new regex you have edited the previous one to works fine, and doesn't match anything with a underscore in. You may have an issue in your code implementation.
Yes, this should work. You alternatively like to use something like:
^[A-Za-z]+$
to ensure that there is at least one alphabetic character. What language are you using? In python, this would be better achieved with the isalpha() function. There may be similar functions in your chosen language. Also, in a lot of implementations of regular expressions, you can simply do:
^\a+$
In some regular expression implementations (POSIX in particular), the + needs to be \+.
^[a-zA-Z]+$ should do the job. But when you want to catch sentence with spaces,
^[a-zA-Z\s]+$ will be better, where \s means space for this one. Or you may even extending it to catch punctuations character also.
"aaa_aaa" is still a match because it matches the first block of a's. By incorporating the '^' and'$' into your expression, you are indicating that the start of linemust first match, followed by a block of letters, followed by the end of line. This essentially means the whole string must match the expression.
using System;
using System.Text.RegularExpressions;
public class Test
{
public static void Main() {
if (Regex.IsMatch("aaa_aa", "^[a-zA-Z]*$"))
Console.WriteLine("Pigs can fly");
}
}