Strings

A Go string is an immutable sequence of UTF-8 encoded bytes. Once created, a string cannot be modified — operations that appear to change a string always produce a new one.

Declaring Strings

var s1 string = "Hello, World!"
s2 := "Go is awesome" // type inferred as string

Output:

s1: Hello, World! | type: string
s2: Go is awesome | type: string

String Length

len() returns the number of bytes, not characters. For ASCII strings these are the same, but a multi-byte Unicode character counts as more than one byte.

fmt.Println("Length of s1:", len("Hello, World!")) // 13

Concatenation

Use + to join strings:

s3 := "Hello, World!" + " " + "Go is awesome"
fmt.Println(s3) // Hello, World! Go is awesome

Raw String Literals

Backtick strings are raw — backslash sequences are not processed, and the string can span multiple lines:

s4 := `This is a
multi-line
string`
fmt.Println(s4)

Output:

This is a
multi-line
string

Byte Indexing

s[i] returns the byte at index i as a uint8 value:

fmt.Println("First byte of s1:", "Hello, World!"[0])      // 72
fmt.Printf("First character of s1: %c\n", "Hello, World!"[0]) // H

For Unicode-safe character iteration, use range — see Loops.

Key Takeaways

• Immutable: strings cannot be modified after creation — operations produce new strings
• UTF-8 encoded: Go source files and strings are UTF-8 by default
• len() counts bytes: not characters — a multi-byte Unicode character counts as more than 1
• Raw literals: backtick strings preserve backslashes literally and support multiple lines
• Byte indexing: s[i] returns a uint8 — use range for Unicode-safe character access

Related Topics

• Bytes — byte (uint8), the unit that strings are made of
• Runes — Unicode-aware character type for iterating strings
• Strings and Formatting — escape characters, fmt.Printf verbs, and more
• Go Types — other built-in types