Lua常用自定义函数

去除字符串首尾的空格

function trim(s)
  return (string.gsub(s, "^%s*(.-)%s*$", "%1")) 
end
string1 = "   RUNOOB        "
string2 = trim(string1)
print(string2)

打印table

function print_r ( t )  
    local print_r_cache={}
    local function sub_print_r(t,indent)
        if (print_r_cache[tostring(t)]) then
            print(indent.."*"..tostring(t))
        else
            print_r_cache[tostring(t)]=true
            if (type(t)=="table") then
                for pos,val in pairs(t) do
                    if (type(val)=="table") then
                        print(indent.."["..pos.."] => "..tostring(t).." {")
                        sub_print_r(val,indent..string.rep(" ",string.len(pos)+8))
                        print(indent..string.rep(" ",string.len(pos)+6).."}")
                    elseif (type(val)=="string") then
                        print(indent.."["..pos..'] => "'..val..'"')
                    else
                        print(indent.."["..pos.."] => "..tostring(val))
                    end
                end
            else
                print(indent..tostring(t))
            end
        end
    end
    if (type(t)=="table") then
        print(tostring(t).." {")
        sub_print_r(t,"  ")
        print("}")
    else
        sub_print_r(t,"  ")
    end
    print()
end

table去重

table = {1 , 2 , 3 , 4 , 20 , 6 , 7 , 7 , 15 , 28};
function table_unique(t) 
    local check = {};
    local n = {};
    for key , value in pairs(t) do
        if not check[value] then
            n[key] = value
            check[value] = value
        end
    end
    return n
end 

for key , value in pairs(table_unique(table)) do
    print('value is ' , value)
end

table的长度

当我们获取 table 的长度的时候无论是使用 # 还是 table.getn 其都会在索引中断的地方停止计数，而导致无法正确取得 table 的长度。

可以使用以下方法来代替：

function table_leng(t)
  local leng=0
  for k, v in pairs(t) do
    leng=leng+1
  end
  return leng;
end

table最大值

table.maxn 在 Lua5.2 之后该方法已经不存在了，我们定义了 table_maxn 方法来实现。

function table_maxn(t)
  local mn=nil;
  for k, v in pairs(t) do
    if(mn==nil) then
      mn=v
    end
    if mn < v then
      mn = v
    end
  end
  return mn
end
tbl = {[1] = 2, [2] = 6, [3] = 34, [26] =5}
print("tbl 最大值：", table_maxn(tbl))
print("tbl 长度 ", #tbl)

将阿拉伯数字转换为语文汉字数字

local function NumToCN(num)
    local size = #tostring(num)
    local CN = ""
    local StrCN = {"一","二","三","四","五","六","七","八","九"}
    for i = 1 , size do
        CN = CN .. StrCN[tonumber(string.sub(tostring(num), i , i))]
    end
    return CN
end
print(NumToCN(56665))