Golang Determine if String contains a String (with wildcards) - string

Question

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

Answer 1

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
}
Run it on the Go PlayGround.

Answer 2

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 + "$"
}
var result strings.Builder
for i, literal := range components {
// Replace * with .*
if i > 0 {
result.WriteString(".*")
}
// Quote any regular expression meta characters in the
// literal text.
result.WriteString(regexp.QuoteMeta(literal))
}
return "^" + result.String() + "$"
}
Run it on the Go Playground