strings package essentials

package main

import (
    "fmt"
    "strings"
)

func main() {
    s := "  Hello, World! Hello, Go!  "

    fmt.Println(strings.TrimSpace(s))             // "Hello, World! Hello, Go!"
    fmt.Println(strings.ToLower(s))               // ... lowercased
    fmt.Println(strings.Contains(s, "World"))     // true
    fmt.Println(strings.HasPrefix(strings.TrimSpace(s), "Hello"))  // true

    // Counting
    fmt.Println(strings.Count(s, "Hello"))        // 2

    // Split / Join
    parts := strings.Split("a,b,c,d", ",")
    fmt.Println(parts)                            // [a b c d]
    fmt.Println(strings.Join(parts, "|"))         // a|b|c|d

    // Replace — N=-1 means replace all
    fmt.Println(strings.Replace(s, "Hello", "Hi", -1))
    // Or use the dedicated ReplaceAll:
    fmt.Println(strings.ReplaceAll(s, "Hello", "Hi"))

    // Fields — split on ANY whitespace, drop empty entries
    fmt.Println(strings.Fields("  foo  bar\tbaz\n"))   // [foo bar baz]
}