gsub 功能

不要与 string.sub 函数混淆，后者返回一个子字符串！

这个怎么运作

字符串参数

("hello world"):gsub("o", "0")
    --> returns "hell0 w0rld", 2
    -- the 2 means that 2 substrings have been replaced (the 2 Os)

("hello world, how are you?"):gsub("[^%s]+", "word")
    --> returns "word word, word word word?", 5

("hello world"):gsub("([^%s])([^%s]*)", "%2%1")
    --> returns "elloh orldw", 2

函数参数

local word = "[^%s]+"

function func(str)
    if str:sub(1,1):lower()=="h" then
        return str
    else
        return "no_h"
    end
end
("hello world"):gsub(word, func)
    --> returns "hello no_h", 2

表参数

local word = "[^%s]+"

sub = {}
sub["hello"] = "g'day"
sub["world"] = "m8"

("hello world"):gsub(word, sub)
    --> returns "g'day m8"

("hello world, how are you?"):gsub(word, sub)
    --> returns "g'day m8, how are you?"
    -- words that are not in the table are simply ignored