Lua: string.rep nested inside string.gsub?

Question

I would like to be able to take a string and repeat every substring following a number that amount of times while removing the number. For example "5 north, 3 west" --> "north north north north north, west west west". This is what I tried:

test = "5 north, 3 west"
test = test:gsub("(%d) (%w+)", string.rep("%2 ", tonumber("%1")) )
Note(test)

But I just get an error like "number expected got Nil."

Answer 1

You need to use a function as the second parameter to gsub:

test = "5 north, 3 west"
test = test:gsub("(%d) (%w+)",
  function(s1, s2) return string.rep(s2.." ", tonumber(s1)) end)
print(test)

This prints north north north north north , west west west.