Dexterity: Checking for Special Characters in a String

David Meego - Click for blog homepageToday, I responded on a Partner Forum thread about evaluating the contents of a string field. The question was:

Is there a function that evaluates a string field to determine if it contains any special characters?

I have written similar code in the past and decided to quickly create a function to perform two functions:

  1. Return a Boolean to indicate if a special character has been found
  2. Pass out a string containing only the normal (non-special) characters

This function identifies alphabetic (optionally including space) and numeric characters as normal and anything else as “special”.

Global Function: IsSpecial

function returns boolean OUT_Special;
in string IN_String;
in boolean IN_SpaceAllowed;
out string OUT_Stripped;

local string l_char;
local string l_string;
local integer i;

OUT_Special = false;

clear l_string;
for i = 1 to length(IN_String) do
	l_char = substring(IN_String, i, 1);
	if isalpha(l_char, IN_SpaceAllowed) or (l_char >= str(0) and l_char <= str(9)) then
		l_string = l_string + l_char;
		OUT_Special = true;
	end if;
end for;

OUT_Stripped = l_string;

The function uses the Dexterity isalpha() function as this will handle the extra extended alphabetic characters beyond the normal A to Z and a to z ranges such as é è ë ö ÿ etc.

I have also provided the option to decide whether spaces are to be included as alphabetic.

Hope you find this helpful.


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