CODEWITHSUNDEEP
luagsubopenrestylua-patterns
SweetNGX
SweetNGX

Reputation: 163

LUA delete 2 different characters with gsub

I want to delete two different characters at the beginning and end of my_string with gsub.. But I managed to delete only one..

    local my_string  = "[I wish you a happy birthday]"
    local new_string = bouquet:gsub('%]', '')
    print(new_string)

How can I create the right gsub pattern?

Upvotes: 1

Views: 556

Answers (4)

koyaanisqatsi
koyaanisqatsi

Reputation: 2793

So...

do
local my_string="[I wish you a happy birthday]"
local new_string=my_string:gsub('[%[%]]','',2)
print(new_string)
end

...leads to the desired output. The % escapes the [ and ] - Like in other languages the \ do.

Upvotes: 0

Renshaw
Renshaw

Reputation: 1155

Since you know the basic pattern for gsub, I suggest a easy way to solve you problem.

local new_string = my_string:gsub('%]',''):gsub('%[','')

Upvotes: 0

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626926

You can use

local new_string = my_string:gsub('^%[(.*)]$', '%1')

See this Lua demo. The ^%[(.*)]$ pattern matches

  • ^ - start of string
  • %[ - a literal [ char
  • (.*) - captures any zero or more chars into Group 1 (%1 refers to this value from the replacement pattern)
  • ] - a ] char
  • $ - end of string.

Alternatively, you can use

local new_string = string.gsub(my_string:gsub('^%[', ''), ']$', '')

See this Lua demo online.

The ^%[ pattern matches a [ at the start of the string and ]$ matches the ] char at the end of the string.

If there is no need to check if [ and ] positions, just use

local new_string = my_string:gsub('[][]', '')

See the Lua demo.

The [][] pattern matches either a ] char or a [ char.

Upvotes: 1

DarkWiiPlayer
DarkWiiPlayer

Reputation: 7066

you can do something like this:

local new_string = my_string:match("^%[(.*)]$")

explanation: Match a string that starts with [ and ends with ] and return just what's between the two. For any other strings, it will just return them as is.

Upvotes: 2

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