I am working on a project where i have to validate the BECS characters. Bulk Electronic Clearing System (BECS) only allowed the following characters.
BECS Character set
Type Description
Numeric 0 to 9
Alphabetic Uppercase A to Z and Lowercase a to z
+ Plus sign
- Minus sign or hyphen
@ At sign
SP Blank space
$ Dollar sign
! Exclamation mark
% Percentage sign
& Ampersand
( Left Parenthesis
) Right Parenthesis
* Asterik
. Period or decimal point
/ Solidus (slash)
# Number Sign (Pound or Hash)
= Equal Sign
: Colon
; Semicolon
? Question mark
, Comma
’ Apostrophe
[ Left square bracket
] Right square bracket
_ Low line (underscore)
^ Circumflex
I have tried the following but not working:
preg_match("/^[A-Za-z0-9^_[]',?;:=#/.*()&%!$ @+-]+$/", $string);
Inside character classes, you don't need to escape most of the metacharacters.
/^[A-Za-z0-9^_[\]',?;:=#\/.*()&%!$ @+-]+$/
] is escaped to prevent it from closing the character class/ needs to be escaped because we're using it as regex delimiter- doesn't need to be escaped because it's the last character in the class^ doesn't need to be escaped because it's not the first character in the classOr, if you want a shorter expression, the following regex covers the same range:
/^[ !#-;=?-[\]^_a-z]+$/
you have to escape most of the chars in your string as they have special meaning in regular expressions
(of course you were right not to escape the leading ^ and the trailing $ as they indicate that no other character can be in the line):
preg_match("/^[A-Za-z0-9\\^_\\[\\]',\\?;:=#/\\.\\*\\(\\)\\&\\%!\\$ @\\+\\-]+$/", $string);
For the record a list of the BECS allowed chars vs regular expression chars:
Type Description
Numeric 0 to 9
Alphabetic Uppercase A to Z and Lowercase a to z
+ Plus sign: means 1 or more
- Minus sign or hyphen: used for char range
$ Dollar sign: end of line
( Left Parenthesis: starts a group
) Right Parenthesis: ends a group
* Asterik: 0 or more
. Period or decimal point: any char (not in a range, would work)
? Question mark: 0 or 1
[ Left square bracket: starts a range
] Right square bracket: ends a range
^ Circumflex: not/line start
Instead of worrying about escaping manually use preg_quote
The code would then be preg_match("/^[A-Za-z0-9".preg_quote("^_[]',?;:=#/.*()&%!$ @+-", "/")."]+$/", $string);