EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

Regular Expressions

A "search string" below is the string containing the pattern, a "target string" is the string being searched for a possible match with the pattern.

• "^" at the start of the search string: Match following search string at the start of the target string; otherwise the search string can start anywhere in the target string. To search for a genuine "^" anywhere, use "\^".
• "$" at the end of the search string: Match preceding search string at the end of the target string; otherwise the search string can end anywhere in the target string. To search for a genuine "$" anywhere, use "\$".
• ".": Stands for an arbitrary character; to search for a genuine ".", use "\."
• "[xyz]": Stands for one character belonging to the string contained in brackets (example: "[abc]" means one of a, b, c).
• "[a-ex-z]": Stands for ranges of characters (example: "[a-zA-Z]" means any letter).
• "[^xyz]" (i.e. a "^" as first character in a square bracket): Stands for exclusion of all characters in the list, i.e. "[^a-z]" means "any character but a lower case letter".
• "*": Allows zero or more repetitions of the preceding character, either specified directly, or from a list. (examples: "a*" means zero or more occurrences of "a", "[A-Z]*" means zero or more upper-case letters).
• "backslash-c" (e.g. "\."): Removes the special meaning of character c.

select,flag=twiss,pattern="^d..$" ;
select,flag=twiss,pattern="^k.*qd.*\.r1$" ;