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I have one question related with regular expression. In my case, I have to make sure that first letter is alphabet, second onwards it can be any alphanumeric + some special characters.
Regards, Anto
395
An alphanumeric example are the characters a, H, 0, 5 and k. These characters are contrasted to non-alphanumeric ones, which are anything other than letters and numbers. Examples of non-alphanumeric numbers include &, $, @, -, %, *, and empty space.
Special Regex Characters: These characters have special meaning in regex (to be discussed below): . , + , * , ? , ^ , $ , ( , ) , [ , ] , { , } , | , \ . Escape Sequences (\char): To match a character having special meaning in regex, you need to use a escape sequence prefix with a backslash ( \ ). E.g., \. matches "."
Basically (0+1)* mathes any sequence of ones and zeroes. So, in your example (0+1)*1(0+1)* should match any sequence that has 1. It would not match 000 , but it would match 010 , 1 , 111 etc. (0+1) means 0 OR 1.
Try something like this:
^[a-zA-Z][a-zA-Z0-9.,$;]+$
Explanation:
^ Start of line/string. [a-zA-Z] Character is in a-z or A-Z. [a-zA-Z0-9.,$;] Alphanumeric or `.` or `,` or `$` or `;`. + One or more of the previous token (change to * for zero or more). $ End of line/string.
The special characters I have chosen are just an example. Add your own special characters as appropriate for your needs. Note that a few characters need escaping inside a character class otherwise they have a special meaning in the regular expression.
I am assuming that by "alphabet" you mean A-Z. Note that in some other countries there are also other characters that are considered letters.
More information
151
Try this :
/^[a-zA-Z]/
where
^ -> Starts with
[a-zA-Z] -> characters to match
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