ligo/gitlab-pages/docs/reference/string.md

id	title	description	hide_table_of_contents
string-reference	String	Operations for strings.	true

import Syntax from '@theme/Syntax'; import SyntaxTitle from '@theme/SyntaxTitle';

function length : string -> nat val length : string -> nat let length: string => nat

Get the size of a string.

Michelson only supports ASCII strings so for now you can assume that each character takes one byte of storage.

function string_size (const s: string) : nat is String.length(s)

Note that size and String.size are deprecated.

let size_op (s: string) : nat = String.length s

Note that String.size is deprecated.

let size_op = (s: string): nat => String.length(s);

Note that String.size is deprecated.

function sub : nat -> nat -> string -> string val sub : nat -> nat -> string -> string let sub: (nat, nat, string) => string

Extract a substring from a string based on the given offset and length. For example the string "abcd" given to the function below would return "bc".

function slice_op (const s : string) : string is String.sub(1n , 2n , s)

Note that string_slice is deprecated.

let slice_op (s: string) : string = String.sub 1n 2n s

Note that String.slice is deprecated.

let slice_op = (s: string): string => String.sub(1n, 2n, s);

Note that String.slice is deprecated.

function concat : string -> string -> string val concat : string -> string -> string let concat: (string, string) => string

Concatenate two strings and return the result.

function concat_op (const s : string) : string is String.concat(s, "toto")

Alternatively:

function concat_op_alt (const s : string) : string is s ^ "toto"

let concat_syntax (s: string) = String.concat s "test_literal"

Alternatively:

let concat_syntax_alt (s: string) = s ^ "test_literal"

let concat_syntax = (s: string) => String.concat(s, "test_literal");

Alternatively:

let concat_syntax_alt = (s: string) => s ++ "test_literal";