// Compare is included only for symmetry with package bytes. // It is usually clearer and always faster to use the built-in // string comparison operators ==, <, >, and so on. func Compare(a, b string) int

忽略大小寫(xiě)比較

有時(shí)候要忽略大小寫(xiě)比較, 可以使用strings.EqualFold 字符串比較是否相等
源碼實(shí)現(xiàn)

// 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
}

通過(guò)源碼可看到 if 'A' <= sr && sr <= 'Z' && tr == sr+'a'-'A' 可以看到不區(qū)分大小寫(xiě)的實(shí)現(xiàn)。
看個(gè)完整測(cè)試代碼：

// 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"))
}