Go 字符串比较的实现示例

目录

• compare 和 equalfold 区别
• 忽略大小写比较

#### 代码示例
```go
fmt.println("go"=="go")
fmt.println("go"=="go")

fmt.println(strings.compare("go","go"))
fmt.println(strings.compare("go","go"))

fmt.println(strings.equalfold("go","go"))

// equalfold reports whether s and t, interpreted as utf-8 strings,
// are equal under unicode case-folding, which is a more general
// form of case-insensitivity.
func equalfold(s, t string) bool {
    for s != "" && t != "" {
        // extract first rune from each string.
        var sr, tr rune
        if s[0] < utf8.runeself {
            sr, s = rune(s[0]), s[1:]
        } else {
            r, size := utf8.decoderuneinstring(s)
            sr, s = r, s[size:]
        }
        if t[0] < utf8.runeself {
            tr, t = rune(t[0]), t[1:]
        } else {
            r, size := utf8.decoderuneinstring(t)
            tr, t = r, t[size:]
        }

        // if they match, keep going; if not, return false.

        // easy case.
        if tr == sr {
            continue
        }

        // make sr < tr to simplify what follows.
        if tr < sr {
            tr, sr = sr, tr
        }
        // fast check for ascii.
        if tr < utf8.runeself {
            // ascii only, sr/tr must be upper/lower case
            if 'a' <= sr && sr <= 'z' && tr == sr+'a'-'a' {
                continue
            }
            return false
        }

        // general case. simplefold(x) returns the next equivalent rune > x
        // or wraps around to smaller values.
        r := unicode.simplefold(sr)
        for r != sr && r < tr {
            r = unicode.simplefold(r)
        }
        if r == tr {
            continue
        }
        return false
    }

    // one string is empty. are both?
    return s == t
}

// golang program to illustrate the
// strings.equalfold() function
package main

// importing fmt and strings
import (
    "fmt"
    "strings"
)

// calling main method
func main() {
    // case insensitive comparing and returns true.
    fmt.println(strings.equalfold("geeks", "geeks"))

    // case insensitive comparing and returns true.
    fmt.println(strings.equalfold("computerscience", "computerscience"))
}