A string can be compared to a wild-card pattern with the wcmatch function.
This can be helpful when needing to build a dynamic selection set (in conjunction with ssget) or to retrieve extended entity data by application name (in conjunction with entget). The wcmatch function compares a single string to a pattern. The function returns T if the string matches the pattern, and nil if it does not. The wild-card patterns are similar to the regular expressions used by many system and application programs.
The following rules apply to wild-card patterns:
- Alphabetic characters and numerals are treated literally in the pattern.
- Brackets can be used to specify optional characters or a range of letters or digits.
- A question mark ( ? ) matches a single character.
- An asterisk ( * ) matches a sequence of characters; and, certain other special characters have special meanings within the pattern. When you use the * character at the beginning and end of the search pattern, you can locate the desired portion anywhere in the string.
In the following examples, a string variable called matchme has been declared and initialized:
(setq matchme "this is a string - test1 test2 the end") "this is a string - test1 test2 the end"
The following code checks whether or not matchme begins with the four characters "this":
(wcmatch matchme "this*") T
The following code illustrates the use of brackets in the pattern. In this case, wcmatch returns T if matchme contains "test4", "test5", "test6" (4-6), or "test9" (note the use of the * character):
(wcmatch matchme "*test[4-69]*") nil
In this case, wcmatch returns nil because matchme does not contain any of the strings indicated by the pattern. However, using the pattern "test[4-61]" does match the string because it contains “test1”.
(wcmatch matchme "*test[4-61]*") T
The pattern string can specify multiple patterns, separated by commas. The following code returns T if matchme equals "ABC", or if it begins with "XYZ", or if it ends with "end".
(wcmatch matchme "ABC,XYZ*,*end") T