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wcmatch - AutoCAD AutoLISP function

wcmatch is an AutoLISP function that performs a wild-card pattern match on a string.

Syntax: (wcmatch string pattern)

Where the arguments are string an pattern:
string
A string to be compared. The comparison is case-sensitive, so uppercase and lowercase characters must match.
pattern
A string containing the pattern to match against string. The pattern can contain the wild-card pattern-matching characters shown in the table Wild-card characters. You can use commas in a pattern to enter more than one pattern condition. Only the first 500 characters (approximately) of the string and pattern are compared; anything beyond that is ignored.

Both arguments can be either a quoted string or a string variable. It is valid to use variables and values returned from AutoLISP functions for string and pattern values.

Return Values
If string and pattern match, wcmatch returns T; otherwise, wcmatch returns nil.

Wild-card characters
Character Definition
# (pound) Matches any single numeric digit.
@ (at) Matches any single alphabetic character.
. (period) Matches any single nonalphanumeric character.
* (asterisk) Matches any character sequence, including an empty one, and it can be used anywhere in the search pattern: at the beginning, middle, or end.
? (question mark) Matches any single character.
~ (tilde) If it is the first character in the pattern, it matches anything except the pattern.
[...] Matches any one of the characters enclosed.
[~...] Matches any single character not enclosed.
- (hyphen) Used inside brackets to specify a range for a single character.
, (comma) Separates two patterns.
` (reverse quote) Escapes special characters (reads next character literally).

Examples
The following command tests a string to see if it begins with the character N:
Command: (wcmatch "Name" "N*")
T

The following example performs three comparisons. If any of the three pattern conditions is met, wcmatch returns T. The tests are:
Does the string contain three characters?
Does the string not contain an m?
Does the string begin with the letter “N”?

If any of the three pattern conditions is met, wcmatch returns T:
Command: (wcmatch "Name" "???,~*m*,N*")
T

In this example, the last condition was met, so wcmatch returned T.

Using Escape Characters with wcmatch
To test for a wild-card character in a string, you can use the single reverse-quote character (`) to escape the character. Escape means that the character following the single reverse quote is not read as a wild-card character; it is compared at its face value. For example, to search for a comma anywhere in the string “Name”, enter the following:
Command: (wcmatch "Name" "*`,*")
nil

Both the C and AutoLISP programming languages use the backslash (\) as an escape character, so you need two backslashes (\\) to produce one backslash in a string. To test for a backslash character anywhere in “Name”, use the following function call:
Command: (wcmatch "Name" "*`\\*")
nil

All characters enclosed in brackets ([ . . . ]) are read literally, so there is no need to escape them, with the following exceptions: the tilde character (~) is read literally only when it is not the first bracketed character (as in "[A~BC]"); otherwise, it is read as the negation character, meaning that wcmatch should match all characters except those following the tilde (as in "[~ABC]"). The dash character (-) is read literally only when it is the first or last bracketed character (as in "[-ABC]" or "[ABC-]") or when it follows a leading tilde (as in "[~-ABC]"). Otherwise, the dash character (-) is used within brackets to specify a range of values for a specific character. The range works only for single characters, so "STR[1-38]" matches STR1, STR2, STR3, and STR8, and "[A-Z]" matches any single uppercase letter.
The closing bracket character (]) is also read literally if it is the first bracketed character or if it follows a leading tilde (as in "[ ]ABC]" or "[~]ABC]").

Note! Because additional wild-card characters might be added in future releases of AutoLISP, it is a good idea to escape all nonalphanumeric characters in your pattern to ensure upward compatibility.

 

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