`স্ট্রিংস` এবং `strconv`

import "strings"

strings.ToUpper("ciao")              // "CIAO"
strings.ToLower("CIAO")              // "ciao"
strings.Contains("ciao mondo", "mo") // true
strings.HasPrefix("foo.txt", "foo")  // true
strings.HasSuffix("foo.txt", ".txt") // true
strings.Index("ciao", "a")           // 2 (or -1 if absent)
strings.Count("banana", "a")         // 3

strings.Split("a,b,c", ",")               // []string{"a","b","c"}
strings.SplitN("a,b,c,d", ",", 2)         // []string{"a","b,c,d"}
strings.Join([]string{"a","b"}, "-")     // "a-b"

strings.TrimSpace("  ciao\n")             // "ciao"
strings.Trim("__ciao__", "_")             // "ciao"
strings.ReplaceAll("aaa", "a", "b")       // "bbb"
strings.Replace("aaa", "a", "b", 2)       // "bba"  (limit 2)

key, val, ok := strings.Cut("name=Ada", "=")
// "name", "Ada", true

var b strings.Builder
for i := 0; i < 1000; i++ {
    b.WriteString("x")
}
out := b.String()

import "strconv"

n, err := strconv.Atoi("42")     // int   from decimal
s := strconv.Itoa(42)             // "42"
b, err := strconv.ParseBool("true")

// Generic versions with base and optional bit-size
i64, err := strconv.ParseInt("ff", 16, 64) // 255
u64, err := strconv.ParseUint("7", 10, 8)  // 7
f, err := strconv.ParseFloat("3.14", 64)   // 3.14

// Number → string
strconv.FormatInt(255, 16)                  // "ff"
strconv.FormatFloat(3.14, 'f', 2, 64)       // "3.14"
strconv.FormatBool(true)                    // "true"

n, err := strconv.Atoi(input)
switch {
case errors.Is(err, strconv.ErrSyntax):
    return fmt.Errorf("input non numerico: %q", input)
case errors.Is(err, strconv.ErrRange):
    return fmt.Errorf("numero fuori range: %q", input)
case err != nil:
    return err
}
_ = n