Strings

String "interpolations"

Doc with replacements %d %s, etc
https://pkg.go.dev/fmt#hdr-Printing

str := fmt.Sprintf("the number is: %d", 1)
str1 := fmt.Sprintf("the number is: %s", "one")
fmt.Println("interpolated: ", str, str1)

The rune and byte types

this is a rune
With rune is possible to store utf8 characters in a single value
rune is int32

var fullChar rune
// can only be one character, just like char in other languages
fullChar = 'é'
fmt.Println("full char: ", fullChar) // -> 233

byte is uint8
in go string is a sequence of bytes readonly, in that way is note possible to acess [0] [1] of a string
A more deep detail is that it is not called a cast it is called a convertion and the value is copied in memory from string to bytes
original string keeps intact
it returns two bytes because é is no ascii(using 7 bits, from 0 to 127)

var notFull []byte
notFull = []byte("é")
fmt.Println("not full char: ", notFull) // -> [195, 169]

Strings in a loop

chars := "é😍😋...😋.😋.😅"
// in loop string is interated as runes
for idx, char := range chars {
	// char is type rune
	fmt.Println(idx, char)
}

Replace

It is possible to get strings by range
get from 3 until end of string

newString := "  testando"
fmt.Println("new String: ", newString[3:])

replace string

fmt.Println("string replaced: ", strings.ReplaceAll("valter", "v", "w"))

Or using regex

using regex, the (?im) is to change mode of regex, in that case is using case insensitive and multiline regex

reg1 := regexp.MustCompile(`(?im)V`)
fmt.Println("string replaced2: ", reg1.ReplaceAllString("valter", "w"))