Strings in Go

Disclaimer: This article don’t pretend to teach you anything, it’s just part of my notes. If it could be helpful for somebody, great :)

Strings are sequences of bytes. And thouse bytes are counted from zero to the lenght of the string minus one.

var str string = "Notes about string in Golang"
var length int = len(str)

Index operations

We can get the byte in the string with a given index using this

var c byte = str[2]

Substrings

We can get a piece from the string

var c string = str[3:7]
fmt.Println(c)

Substring shortcuts, taking slices

If we want to get all bytes from zero until certain index

var c byte = str[:6]

If we want to get all bytes from certain index until the end of string

var c byte = str[6:]

After a backslash

\a   U+0007 alert or bell
\b   U+0008 backspace
\f   U+000C form feed
\n   U+000A line feed or newline
\r   U+000D carriage return
\t   U+0009 horizontal tab
\v   U+000b vertical tab
\\   U+005c backslash
\'   U+0027 single quote  
\"   U+0022 double quote  

Most Popular String Functions

1. Compare

fmt.Println(strings.Compare("A", "B"))  // A < B => -1
fmt.Println(strings.Compare("B", "A"))  // B > A  => 1
fmt.Println(strings.Compare("Japan", "Australia")) // J > A => 1

1. Contains

fmt.Println(strings.Contains("Australia", "Aus"))   // Any part of string => true
fmt.Println(strings.Contains("Japan", "JAP")) // Case sensitive => false

1. Count

fmt.Println(strings.Count("Australia", "a")) // => 2

1. EqualFold

fmt.Println(strings.EqualFold("Australia", "aUSTRALIA")) // true
fmt.Println(strings.EqualFold("Australia", "Australia")) // true
fmt.Println(strings.EqualFold("Australia", "Aus")) // true

1. Fields The Fields function breaks a string around each instance of one or more consecutive white space characters into an Array.

testString := "Australia is a country and continent surrounded by the Indian and Pacific oceans."
testArray := strings.Fields(testString)
for _, v := range testArray {    
    fmt.Println(v)
  } 

1. HasPrefix

fmt.Println(strings.HasPrefix("Australia", "Aus")) // => true
fmt.Println(strings.HasPrefix("Australia", "aus")) // => false

1. HasSuffix

fmt.Println(strings.HasSuffix("Australia", "lia")) // => true
fmt.Println(strings.HasSuffix("Australia", "A")) // => false

1. Index

The Index function enables searching particular text within a string.

fmt.Println(strings.Index("Australia", "Aus")) // => 0
fmt.Println(strings.Index("Australia", "aus")) // => -1

1. Join

The Join function return a string from the elements of an slice.

textString := []string{"Australia", "Japan", "Canada"}
fmt.Println(strings.Join(textString, "-")) // => Australia-Japan-Canada

Notes

• String are immutable: once created, it is impossible to change the contents of a string.
• Data type rune is equivalent to int32.
• String literals are enclosed by double quotes.

Resources

https://www.golangprograms.com/golang/string-functions/

https://golang.org/pkg/strings/

https://golang.org/doc/effective_go.html