What's the RegEx to make sure that delimiters are escaped?

Posted by Kuyenda on Stack Overflow See other posts from Stack Overflow or by Kuyenda
Published on 2012-12-02T05:02:01Z Indexed on 2012/12/02 5:03 UTC
Read the original article Hit count: 202

Filed under:

regex

I'm looking for a regular expression that will check whether or not delimiters in a string are escaped with a backward slash.

The delimiters I am concerned about are comma (\,), colon (\:), semicolon (\;) and of course the backward slash itself has to be escaped (\).

For example, the string "test" should return a match because there are no delimiters in it, and no escaping is necessary. The string "te\;st" would return a match because the semicolon delimiter is escaped. "te;st" and "t\;s:t" would both fail because the both contain at least one delimiter that is not escaped.

I know that I need a conditional and a positive look behind, and this is what I have so far, but it is not giving me the expected answer.

^(?<delimiter>[:;,\\])?(?(delimiter)\(?<=(?:\\\\)*\\)k<delimiter>|.)$

Any suggestions on how I can make this work?

Thanks.

Related posts about regex

Find multiple regex in each line and skip result if one of the regex doesn't match

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a list of variables: variables = ['VariableA', 'VariableB','VariableC'] which I'm going to search for, line by line ifile = open("temp.txt",'r') d = {} match = zeros(len(variables)) for line in ifile: emptyCells=0 for i in range(len(variables)): regex = r'('+variables[i]+r')[:|=|\(](-… >>> More
OWASP Regex Repository: Is this regex correct?

as seen on Stack Overflow - Search for 'Stack Overflow'
I was looking at the regular expression for validating various data types from the (OWASP Regex Repository). One of the regular expressions in there is called safetext and looks like: ^[a-zA-Z0-9\s.\-]+$ My first question is: Is this regular expression correct? complementary question If this… >>> More
Make a Perl-style regex interpreter behave like a basic or extended regex interpreter

as seen on Stack Overflow - Search for 'Stack Overflow'
I am writing a tool to help students learn regular expressions. I will probably be writing it in Java. The idea is this: the student types in a regular expression and the tool shows which parts of a text will get matched by the regex. Simple enough. But I want to support several different regex… >>> More
JS regex isn't matching, even thought it works with a regex tester

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm writing a piece of client-side javascript code that takes a function and finds the derivative of it, however, the regex that's supposed to match with the power rule fails to work in the context of the javascript program, even though it sucessfully matches when it's used with an independent regex… >>> More
c# RegEx with "|"

as seen on Stack Overflow - Search for 'Stack Overflow'
I need to be able to check for a pattern with | in them. For example an expression like d*|*t should return true for a string like "dtest|test". I'm no regex hero so I just tried a couple of things, like: Regex Pattern = new Regex("s*\|*d"); //unable to build because of single backslash Regex Pattern… >>> More

Developer IT