program needs to process data with spaces and strings and need to add underscore in strings-CodePudding

Kinda confuse how to solve this one. Like each inversion between letters will be added a pause using the character "_", but this does not apply if there are spaces. There is a ReverseString function with a str parameter of type string which will be the input character data to be reversed.

package main

import "fmt"

func ReverseString(str string) string {
    r := ""
    for i := len(str) - 1; i >= 0; i-- {
        if str[i] >= 0 && string(str[i]) != " " {
            r  = string(str[i])   "_"
        }
    }
    return string(r)
}

func main() {
    fmt.Println(ReverseString("hello world"))
    fmt.Println(ReverseString("i am a student"))
}

var _ = Describe("ReverseString", func() {
    When("input str contains 'Hello World'", func() {
        It("should return 'd_l_r_o_W o_l_l_e_H'", func() {
            Expect(main.ReverseString("Hello World")).To(Equal("d_l_r_o_W o_l_l_e_H"))
        })
    })

CodePudding user response：

Here is one option

func ReverseString(s string) string {
    // split string into array
    sarr := strings.Split(s, "")
    
    // reverse the string array
    for i, j := 0, len(sarr)-1; i < j; i, j = i 1, j-1 {
        sarr[i], sarr[j] = sarr[j], sarr[i]
    }
    // join with underscore
    nstr := strings.Join(sarr, "_")
    // remove the space
    return strings.ReplaceAll(nstr, "_ _", " ") 
}

CodePudding user response：

You are assuming that the string only contains ASCII characters. A Go string typically contains UTF-8 encoded characters (Unicode code points).

package main

import "fmt"

func ReverseString(s string) string {
    us := []rune(s)
    rs := make([]rune, 2*len(us))
    j := len(rs)
    for i, r := range us {
        j--
        rs[j] = r
        if r != ' ' {
            if i 1 < len(us) && us[i 1] != ' ' {
                j--
                rs[j] = '_'
            }
        }
    }
    return string(rs[j:])
}

func main() {
    hello := "hello world"
    fmt.Printf("%q\n", hello)
    fmt.Printf("%q\n", ReverseString(hello))
    student := "i am a student"
    fmt.Printf("%q\n", student)
    fmt.Printf("%q\n", ReverseString(student))
}

https://go.dev/play/p/2ZpYsBQkiiA

"hello world"
"d_l_r_o_w o_l_l_e_h"
"i am a student"
"t_n_e_d_u_t_s a m_a i"