我需要修復格式不正確的錯誤

Question

我想用$替換％符號。我嘗試做一個轉義字符（），但沒有奏效。我正在使用lua 5.1，並且出現格式錯誤。 （以'％'結尾）這使我煩惱，因爲我不知道如何解決它。

io.write("Search: ") search = io.read() 
local query = search:gsub("%", "%25") -- Where I put the % sign. 
query = query:gsub("+", "%2B") 
query = query:gsub(" ","+") 
query = query:gsub("/", "%2F") 
query = query:gsub("#", "%23") 
query = query:gsub("$", "%24") 
query = query:gsub("@", "%40") 
query = query:gsub("?", "%3F") 
query = query:gsub("{", "%7B") 
query = query:gsub("}","%7D") 
query = query:gsub("[","%5B") 
query = query:gsub("]","%5D") 
query = query:gsub(">", "%3E") 
query = query:gsub("<", "%3C") 
local url = "https://www.google.com/#q=" .. query 
print(url) 

輸出寫着：

malformed pattern (ends with '%') 

Answer 1

你需要逃避%寫%%。

在Lua怎樣做到這一點的習慣是給一個表來gsub：

local reserved="%+/#$@?{}[]><" 
local escape={} 
for c in reserved:gmatch(".") do 
    escape[c]=string.format("%%%02X",c:byte()) 
end 
escape[" "]="+" 

query = search:gsub(".", escape)