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
print_r函数可以完整的打印table，并且可以清晰的打印table中嵌套table的内容。对于调试和检查程序都有很大的好处。
另外，直接使用print_r不太符合直觉，可以把函数放如table的名字空间里，如下：
table.print = print_r
这样就可以自然的使用这个函数：
table.print( myTable )
打印的结果，类似下面内容：
local myTable = { firstName = "Fred", lastName = "Bob", phoneNumber = "(555) 555-1212", age = 30, favoriteSports = { "Baseball", "Hockey", "Soccer" }, favoriteTeams = { "Cowboys", "Panthers", "Reds" } } table.print_r(myTable)
table: 0x7fa832d012e0 {
[firstName] => "Fred"
[favoriteSports] => table: 0x7fa832d012e0 {
[1] => "Baseball"
[2] => "Hockey"
[3] => "Soccer"
}
[phoneNumber] => "(555) 555-1212"
[favoriteTeams] => table: 0x7fa832d012e0 {
[1] => "Cowboys"
[2] => "Panthers"
[3] => "Reds"
}
[lastName] => "Bob"
[age] => 30
}原文：http://www.cnblogs.com/leezj/p/4230271.html