Lua gsub second instance

Question

I'm using

local mystring = 'Thats a really nice house.'
string.gsub(mystring,"% ", "/",1)

to replace the first white space character with an slash.

But how to replace only the second occurrence of the white space?

score 5 · Answer 1 · answered Nov 14 '14 at 16:04

You can use a function as replacement value in string.gsub and count the matches yourself:

local mystring = "Thats a really nice house."
local cnt = 0
print( string.gsub( mystring, " ", function( m )
  cnt = cnt + 1
  if cnt == 2 then
    return "/"
  end
end ) )

score 5 · Answer 2 · answered Nov 14 '14 at 16:30

5

Try string.gsub(mystring,"(.- .-) ", "%1/",1).

answered Nov 14 '14 at 16:30

lhf

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@hjpotter92, that is better, yes. – lhf Nov 15 '14 at 02:02

score 3 · Accepted Answer · answered Nov 14 '14 at 15:46

You can replace the first instance with something else (assuming the replacement is not present in the string itself, which you can check), then replace it back:

print(mystring:gsub("% ", "\1",1):gsub("% ", "/",1):gsub("\1","% ", 1))

This prints: Thats a/really nice house.. Also, you don't need to escape spaces with %.

Lua gsub second instance

3 Answers3