util.string.insert

local result = util.string.insert(
    input,
    position = nil,
    substring
)

Type	Name	Description
`string`	input	String to insert into
`int`	position	Character position to insert at - negative counts from end - when omitted, substring is appended
`string`	substring	String to insert

Type	Name	Description
`string`	result	String with substring inserted

Append to the end of a string

local result = util.string.insert("hello", "!")

core.engine.print("info", result) -- 'hello!'

Insert at a specific character position

local result = util.string.insert("hello", 1, "X")

core.engine.print("info", result) -- 'Xhello'

Insert in the middle of a string

local result = util.string.insert("hllo", 2, "e")

core.engine.print("info", result) -- 'hello'

Use a negative position to insert from the end

local result = util.string.insert("hello", -1, "p")

core.engine.print("info", result) -- 'hellpo'