Differences between strings.Contains and strings.ContainsAny in Golang

Question

In the source code:

// Contains returns true if substr is within s.
func Contains(s, substr string) bool {
    return Index(s, substr) >= 0
}

// ContainsAny returns true if any Unicode code points in chars are within s.
func ContainsAny(s, chars string) bool {
    return IndexAny(s, chars) >= 0
}

the only difference seems to be substr and the Unicode code points in chars. I wrote some test to test both of them. Their behaviors seem to be identical. I don't understand when to use which.

Answer 1

I think two functions are totally different. Contains are used to detect if a string contains a substring. ContainsAny are used to detect if a string contains any chars in the provided string.