golang--判断字符串是否相等

大小写敏感的比较

在对字符串进行大小写敏感的比较时，最基本的字符串比较操作符比使用 strings 包进行比较要快。

大小写不敏感的比较

对于大小写不敏感的比较，EqualFold（Strings 包）比较快。
使用 EqualFold 时先进行字符数量对比，速度会更快。

比较速度

strings.Compare < 运算符 “==” < strings.EqualFold

原因：

1. 都解析了整个字符串。
2. strings.Compare源码使用的也是运算符比较
3. Equalfold 也会逐个字符进行解析，但是当它解析到两个字符串中不同的字符时，就会提前结束。

参考文章

测试方法

compare.go

func compareOperators(a string, b string) bool {
    
    if a == b {
    
        return true
    } else {
    
        return false
    }
}
// strings compare
func compareString(a string, b string) bool {
    
    if strings.Compare(a, b) == 0 {
    
        return true
    }
    return false
}

compare_test.go

import (
    "testing"
)

func BenchmarkCompareOperators(b *testing.B) {
    
    for n := 0; n < b.N; n++ {
    
        compareOperators("This is a string", "This is a strinG")
    }
}

func BenchmarkCompareString(b *testing.B) {
    
    for n := 0; n < b.N; n++ {
    
        compareString("This is a string", "This is a strinG")
    }
}

20 万行的列表文件==>这个文件包含大量的字符串

compareTxt.go

// operator compare
func compareOperatorsTxt(a string) bool {
    
  file, err := os.Open("names.txt")
  result := false;
  if err != nil {
    
    log.Fatalf("failed opening file: %s", err)
  }
  scanner := bufio.NewScanner(file)
  scanner.Split(bufio.ScanLines)
  for scanner.Scan() {
    
    if strings.ToLower(a) == strings.ToLower(scanner.Text()) {
    
      result = true
    }else {
    
      result = false
    }
  }
  file.Close()
  return result
}
// strings compare
func compareStringTxt(a string) bool {
    
  file, err := os.Open("names.txt")
  result := false;
  if err != nil {
    
    log.Fatalf("failed opening file: %s", err)
  }
  scanner := bufio.NewScanner(file)
  scanner.Split(bufio.ScanLines)
  for scanner.Scan() {
    
    if strings.Compare(strings.ToLower(a), strings.ToLower(scanner.Text())) == 0 {
    
      result = true
    }else {
    
      result = false
    }
  }
  file.Close()
  return result
}
// EqualFold compare
func compareEFTxt(a string) bool {
    
  file, err := os.Open("names.txt")
  result := false;
  if err != nil {
    
    log.Fatalf("failed opening file: %s", err)
  }
  scanner := bufio.NewScanner(file)
  scanner.Split(bufio.ScanLines)
  for scanner.Scan() {
    
    if strings.EqualFold(a, scanner.Text()) {
    
      result = true
    }else {
    
      result = false
    }
  }
  file.Close()
  return result
}
//字符串长度相同而字符不同
func compareByCountTxt(a string) bool {
    
    file, err := os.Open("names.txt")
    result := false;
     if err != nil {
    
        log.Fatalf("failed opening file: %s", err)
    }
     scanner := bufio.NewScanner(file)
    scanner.Split(bufio.ScanLines)
     for scanner.Scan() {
    
        if len(a) == len(scanner.Text()) &&  strings.EqualFold(a, scanner.Text()){
    
            result = true
        }else {
    
            result = false
        }
    }
    file.Close()
    return result
}

compareTxt_test.go

func BenchmarkCompareOperatorsTxt(b *testing.B) {
    
    for n := 0; n < b.N; n++ {
    
        compareOperatorsTxt("Immanuel1234")
    }
}
func BenchmarkCompareStringTxt(b *testing.B) {
    
    for n := 0; n < b.N; n++ {
    
        compareStringTxt("Immanuel1234")
    }
}
func BenchmarkEqualFoldTxt(b *testing.B) {
    
    for n := 0; n < b.N; n++ {
    
        compareEFTxt("Immanuel1234")
    }
}
func BenchmarkCompareByCountTxt(b *testing.B){
    
    for n := 0; n < b.N; n++ {
    
        compareByCountTxt("Immanuel1234")
    }
}