Case insensitive string comparison in Go

Question

How do I compare strings in a case insensitive manner?

For example, "Go" and "go" should be considered equal.

Solution 1

https://golang.org/pkg/strings/#EqualFold is the function you are looking for. It is used like this (example from the linked documentation):

package main

import (
    "fmt"
    "strings"
)

func main() {
    fmt.Println(strings.EqualFold("Go", "go"))
}

Solution 2

method 1:

func CompareStringsInCrudeWay(stringA, stringB string) (bool, error) {
  if strings.ToLower(stringA) == strings.ToLower(stringB) {
      return true, nil
  } else {
      return false, nil
  }
}

method 2:

func Compare(stringA, stringB string) bool {
  for i := 0; i < len(stringA); i++ {
      if stringA[i] == stringB[i] {
          continue
      }
      if unicode.ToLower(stringA[i]) != unicode.ToLower(stringB[i]) {
          return false
      }
  }
  return true
}

method 3:

func CompareStringsInEfficientWay(stringA, stringB string) (bool, error) {
   if strings.EqualFold(stringA, stringB) {
      return true, nil
   } else {
      return false, nil
   }
}

method 3 is actually wrapping method 2, and both are efficient. You can check this blog for more explanation.

Comments

[lunicon]

EqualFold not compare :(

[lunicon]

Sorting can use strings.ToLower("Go") < strings.ToLower("go")

[KBN]

> EqualFold not compare @lunicon what do you mean?

[lunicon]

@KBN, compare operation can say "more, less or equals", EqualFold retrun boolean

[Vitaly Zdanevich]

Please paste code as code, not as images.