With Go, how would you determine if a string contains a certain string that includes wildcards? Example:
We're looking for t*e*s*t (the *'s can be any characters and any length of characters.
Input True: ttttteeeeeeeesttttttt
Input False: tset
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3Use a Regex - but if you really want globbing-style wildcards use a glob library like this one: github.com/gobwas/globDai– Dai2020-10-24 02:57:50 +00:00Commented Oct 24, 2020 at 2:57
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Updated the formatting of the post.user3486527– user34865272020-10-24 17:30:42 +00:00Commented Oct 24, 2020 at 17:30
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2 Answers
Use the regexp package by converting the * in your pattern to the .* of regular expressions.
// wildCardToRegexp converts a wildcard pattern to a regular expression pattern.
func wildCardToRegexp(pattern string) string {
var result strings.Builder
for i, literal := range strings.Split(pattern, "*") {
// Replace * with .*
if i > 0 {
result.WriteString(".*")
}
// Quote any regular expression meta characters in the
// literal text.
result.WriteString(regexp.QuoteMeta(literal))
}
return result.String()
}
Use it like this:
func match(pattern string, value string) bool {
result, _ := regexp.MatchString(wildCardToRegexp(pattern), value)
return result
}
1 Comment
user3486527
Thank you. It appears that this does the trick: ` package main import ( "fmt" "regexp" ) func main() { matched, err := regexp.MatchString(
.*t.*e.*s.*t.*, "tttteeeessssstttttt") fmt.Println(matched, err) matched, err = regexp.MatchString(.*t.*e.*s.*t.*, "tset") fmt.Println(matched, err) }`Good piece of code. I would offer one minor change. It seems to me that if you're using wildcards, then the absence of wildcards should mean exact match. To accomplish this, I use an early return....
func wildCardToRegexp(pattern string) string {
components := strings.Split(pattern, "*")
if len(components) == 1 {
// if len is 1, there are no *'s, return exact match pattern
return "^" + pattern + "$"
}
var result strings.Builder
for i, literal := range components {
// Replace * with .*
if i > 0 {
result.WriteString(".*")
}
// Quote any regular expression meta characters in the
// literal text.
result.WriteString(regexp.QuoteMeta(literal))
}
return "^" + result.String() + "$"
}
3 Comments
Raphael Jenni
the end result should also contain the
"^" + ... + "$" pattern. Otherwise test* also matches 1test.
Robert Purdom
Good catch @RaphaelJenni I've updated the code and playground to include your feedback.
JUSHJUSH
f len(components) == 1 { check if there's any *, but ignores other expression characters. I think we have to escape it before retruning: return "^" + regexp.QuoteMeta(pattern) + "$"