关于 lua：如何将表转储到控制台？

How to dump a table to console?

我无法显示包含嵌套表(n-deep)的表的内容。我想通过 print 语句或快速而肮脏的东西将它转储到标准输出或控制台，但我不知道如何。我正在寻找使用 gdb 打印 NSDictionary 时得到的粗略等价物。

我发现这个很有用。因为如果递归它也可以打印嵌套表。它没有在输出中给出最漂亮的格式，但是对于这样一个简单的功能，它很难在调试时被击败。

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function dump(o)
if type(o) == 'table' then
local s = '{ '
for k,v in pairs(o) do
if type(k) ~= 'number' then k = '"'..k..'"' end
s = s .. '['..k..'] = ' .. dump(v) .. ','
end
return s .. '} '
else
return tostring(o)
end
end

例如

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local people = {
{
name ="Fred",
address ="16 Long Street",
phone ="123456"
},

{
name ="Wilma",
address ="16 Long Street",
phone ="123456"
},

{
name ="Barney",
address ="17 Long Street",
phone ="123457"
}

}

print("People:", dump(people))

产生以下输出：

People: { [1] = { ["address"] = 16 Long Street,["phone"] =
123456,["name"] = Fred,} ,[2] = { ["address"] = 16 Long
Street,["phone"] = 123456,["name"] = Wilma,} ,[3] = { ["address"] = 17
Long Street,["phone"] = 123457,["name"] = Barney,} ,}

相关讨论

我知道这个问题已经被标记为已回答，但让我在这里插入我自己的库。它叫做inspect.lua，你可以在这里找到它：

https://github.com/kikito/inspect.lua

它只是一个您可以从任何其他文件中获取的文件。它返回一个将任何 Lua 值转换为人类可读字符串的函数：

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local inspect = require('inspect')

print(inspect({1,2,3})) -- {1, 2, 3}
print(inspect({a=1,b=2})
-- {
-- a = 1
-- b = 2
-- }

它正确缩进子表，并正确处理"递归表"(包含对自身的引用的表)，因此它不会陷入无限循环。它以合理的方式对值进行排序。它还打印元表信息。

问候！

相关讨论

请随意浏览关于表序列化的 Lua Wiki。它列出了如何将表转储到控制台的几种方法。

您只需要选择最适合您的。有很多方法可以做到这一点，但我通常最终使用 Penlight 中的一种：

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> t = { a = { b = { c ="Hello world!", 1 }, 2, d = { 3 } } }
> require 'pl.pretty'.dump(t)
{
a = {
d = {
3
},
b = {
c ="Hello world!",
1
},
2
}
}

相关讨论

找到了这个：

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-- Print contents of `tbl`, with indentation.
-- `indent` sets the initial level of indentation.
function tprint (tbl, indent)
if not indent then indent = 0 end
for k, v in pairs(tbl) do
formatting = string.rep(" ", indent) .. k ..":"
if type(v) =="table" then
print(formatting)
tprint(v, indent+1)
elseif type(v) == 'boolean' then
print(formatting .. tostring(v))
else
print(formatting .. v)
end
end
end

从这里
https://gist.github.com/ripter/4270799

对我来说很好用……

我见过的大多数纯 lua 打印表函数都存在深度递归问题
并且在太深时往往会导致堆栈溢出。这个印刷品
我写的表函数没有这个问题。由于它处理连接的方式，它还应该能够处理非常大的表。在我个人对这个函数的使用中，它在大约一秒钟内输出了 63k 行到文件。

输出还保留了lua语法，脚本可以很容易地修改
如果修改为允许，则通过将输出写入文件来进行简单的持久存储
仅要格式化的数字、布尔值、字符串和表格数据类型。

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function print_table(node)
local cache, stack, output = {},{},{}
local depth = 1
local output_str ="{\
"

while true do
local size = 0
for k,v in pairs(node) do
size = size + 1
end

local cur_index = 1
for k,v in pairs(node) do
if (cache[node] == nil) or (cur_index >= cache[node]) then

if (string.find(output_str,"}",output_str:len())) then
output_str = output_str ..",\
"
elseif not (string.find(output_str,"\
",output_str:len())) then
output_str = output_str .."\
"
end

-- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
table.insert(output,output_str)
output_str =""

local key
if (type(k) =="number" or type(k) =="boolean") then
key ="["..tostring(k).."]"
else
key ="['"..tostring(k).."']"
end

if (type(v) =="number" or type(v) =="boolean") then
output_str = output_str .. string.rep('\\t',depth) .. key .." ="..tostring(v)
elseif (type(v) =="table") then
output_str = output_str .. string.rep('\\t',depth) .. key .." = {\
"
table.insert(stack,node)
table.insert(stack,v)
cache[node] = cur_index+1
break
else
output_str = output_str .. string.rep('\\t',depth) .. key .." = '"..tostring(v).."'"
end

if (cur_index == size) then
output_str = output_str .."\
" .. string.rep('\\t',depth-1) .."}"
else
output_str = output_str ..","
end
else
-- close the table
if (cur_index == size) then
output_str = output_str .."\
" .. string.rep('\\t',depth-1) .."}"
end
end

cur_index = cur_index + 1
end

if (size == 0) then
output_str = output_str .."\
" .. string.rep('\\t',depth-1) .."}"
end

if (#stack > 0) then
node = stack[#stack]
stack[#stack] = nil
depth = cache[node] == nil and depth + 1 or depth - 1
else
break
end
end

-- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
table.insert(output,output_str)
output_str = table.concat(output)

print(output_str)
end

这是一个例子：

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local t = {
["abe"] = {1,2,3,4,5},
"string1",
50,
["depth1"] = { ["depth2"] = { ["depth3"] = { ["depth4"] = { ["depth5"] = { ["depth6"] = { ["depth7"]= { ["depth8"] = { ["depth9"] = { ["depth10"] = {1000}, 900}, 800},700},600},500}, 400 }, 300}, 200}, 100},
["ted"] = {true,false,"some text"},
"string2",
[function() return end] = function() return end,
75
}

print_table(t)

输出：

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{
[1] = 'string1',
[2] = 50,
[3] = 'string2',
[4] = 75,
['abe'] = {
[1] = 1,
[2] = 2,
[3] = 3,
[4] = 4,
[5] = 5
},
['function: 06472B70'] = 'function: 06472A98',
['depth1'] = {
[1] = 100,
['depth2'] = {
[1] = 200,
['depth3'] = {
[1] = 300,
['depth4'] = {
[1] = 400,
['depth5'] = {
[1] = 500,
['depth6'] = {
[1] = 600,
['depth7'] = {
[1] = 700,
['depth8'] = {
[1] = 800,
['depth9'] = {
[1] = 900,
['depth10'] = {
[1] = 1000
}
}
}
}
}
}
}
}
}
},
['ted'] = {
[1] = true,
[2] = false,
[3] = 'some text'
}
}

相关讨论

如前所述，您必须编写它。
这是我的简陋版本：(超级基本的)

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function tprint (t, s)
for k, v in pairs(t) do
local kfmt = '["' .. tostring(k) ..'"]'
if type(k) ~= 'string' then
kfmt = '[' .. k .. ']'
end
local vfmt = '"'.. tostring(v) ..'"'
if type(v) == 'table' then
tprint(v, (s or '')..kfmt)
else
if type(v) ~= 'string' then
vfmt = tostring(v)
end
print(type(t)..(s or '')..kfmt..' = '..vfmt)
end
end
end

示例：

1 2	local mytbl = { ['1']="a", 2, 3, b="c", t={d=1} } tprint(mytbl)

输出(Lua 5.0)：

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table[1] = 2
table[2] = 3
table["1"] ="a"
table["t"]["d"] = 1
table["b"] ="c"

相关讨论

最简单的方法，循环引用处理等等：

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function dump(t, indent, done)
done = done or {}
indent = indent or 0

done[t] = true

for key, value in pairs(t) do
print(string.rep("\\t", indent))

if type(value) =="table" and not done[value] then
done[value] = true
print(key,":\
")

dump(value, indent + 2, done)
done[value] = nil
else
print(key,"\\t=\\t", value,"\
")
end
end
end

相关讨论

我使用自己的函数来打印表格的内容，但不确定它在您的环境中的转换效果如何：

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---A helper function to print a table's contents.
---@param tbl table @The table to print.
---@param depth number @The depth of sub-tables to traverse through and print.
---@param n number @Do NOT manually set this. This controls formatting through recursion.
function PrintTable(tbl, depth, n)
n = n or 0;
depth = depth or 5;

if (depth == 0) then
print(string.rep(' ', n).."...");
return;
end

if (n == 0) then
print("");
end

for key, value in pairs(tbl) do
if (key and type(key) =="number" or type(key) =="string") then
key = string.format("["%s"]", key);

if (type(value) =="table") then
if (next(value)) then
print(string.rep(' ', n)..key.." = {");
PrintTable(value, depth - 1, n + 4);
print(string.rep(' ', n).."},");
else
print(string.rep(' ', n)..key.." = {},");
end
else
if (type(value) =="string") then
value = string.format(""%s"", value);
else
value = tostring(value);
end

print(string.rep(' ', n)..key.." ="..value..",");
end
end
end

if (n == 0) then
print("");
end
end

格式为JSON(以后可以在IDE中"美化")：

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local function format_any_value(obj, buffer)
local _type = type(obj)
if _type =="table" then
buffer[#buffer + 1] = '{"'
for key, value in next, obj, nil do
buffer[#buffer + 1] = tostring(key) .. '":'
format_any_value(value, buffer)
buffer[#buffer + 1] = ',"'
end
buffer[#buffer] = '}' -- note the overwrite
elseif _type =="string" then
buffer[#buffer + 1] = '"' .. obj .. '"'
elseif _type =="boolean" or _type =="number" then
buffer[#buffer + 1] = tostring(obj)
else
buffer[#buffer + 1] = '"???' .. _type .. '???"'
end
end

用法：

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local function format_as_json(obj)
if obj == nil then return"null" else
local buffer = {}
format_any_value(obj, buffer)
return table.concat(buffer)
end
end

local function print_as_json(obj)
print(_format_as_json(obj))
end

print_as_json {1, 2, 3}
print_as_json(nil)
print_as_json("string")
print_as_json {[1] = 1, [2] = 2, three = { { true } }, four ="four"}

顺便说一句，我还写了其他几个解决方案：一个非常快的解决方案，一个带有特殊字符转义的解决方案：https://github.com/vn971/fast_json_encode

相关讨论

恐怕您必须自己编写代码。这是我写的，可能对你有用

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相关讨论

metalua的table.tostring方法其实很完善。它处理嵌套表，缩进级别是可变的，...
见 https://github.com/fab13n/metalua/blob/master/src/lib/metalua/table2.lua

相关讨论

这是我的版本，支持排除表和用户数据

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-- Lua Table View by Elertan
table.print = function(t, exclusions)
local nests = 0
if not exclusions then exclusions = {} end
local recurse = function(t, recurse, exclusions)
indent = function()
for i = 1, nests do
io.write(" ")
end
end
local excluded = function(key)
for k,v in pairs(exclusions) do
if v == key then
return true
end
end
return false
end
local isFirst = true
for k,v in pairs(t) do
if isFirst then
indent()
print("|")
isFirst = false
end
if type(v) =="table" and not excluded(k) then
indent()
print("|->"..k..":"..type(v))
nests = nests + 1
recurse(v, recurse, exclusions)
elseif excluded(k) then
indent()
print("|->"..k..":"..type(v))
elseif type(v) =="userdata" or type(v) =="function" then
indent()
print("|->"..k..":"..type(v))
elseif type(v) =="string" then
indent()
print("|->"..k..":".."""..v..""")
else
indent()
print("|->"..k..":"..v)
end
end
nests = nests - 1
end

nests = 0
print("### START TABLE ###")
for k,v in pairs(t) do
print("root")
if type(v) =="table" then
print("|->"..k..":"..type(v))
nests = nests + 1
recurse(v, recurse, exclusions)
elseif type(v) =="userdata" or type(v) =="function" then
print("|->"..k..":"..type(v))
elseif type(v) =="string" then
print("|->"..k..":".."""..v..""")
else
print("|->"..k..":"..v)
end
end
print("### END TABLE ###")
end

这是一个例子

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t = {
location = {
x = 10,
y = 20
},
size = {
width = 100000000,
height = 1000,
},
name ="Sidney",
test = {
hi ="lol",
},
anotherone = {
1,
2,
3
}
}

table.print(t, {"test" })

打印：

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请注意，根目录不会删除排除项

添加另一个版本。这个也尝试迭代用户数据。

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function inspect(o,indent)
if indent == nil then indent = 0 end
local indent_str = string.rep(" ", indent)
local output_it = function(str)
print(indent_str..str)
end

local length = 0

local fu = function(k, v)
length = length + 1
if type(v) =="userdata" or type(v) == 'table' then
output_it(indent_str.."["..k.."]")
inspect(v, indent+1)
else
output_it(indent_str.."["..k.."]"..tostring(v))
end
end

local loop_pairs = function()
for k,v in pairs(o) do fu(k,v) end
end

local loop_metatable_pairs = function()
for k,v in pairs(getmetatable(o)) do fu(k,v) end
end

if not pcall(loop_pairs) and not pcall(loop_metatable_pairs) then
output_it(indent_str.."[[??]]")
else
if length == 0 then
output_it(indent_str.."{}")
end
end
end

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--~ print a table
function printTable(list, i)

local listString = ''
--~ begin of the list so write the {
if not i then
listString = listString .. '{'
end

i = i or 1
local element = list[i]

--~ it may be the end of the list
if not element then
return listString .. '}'
end
--~ if the element is a list too call it recursively
if(type(element) == 'table') then
listString = listString .. printTable(element)
else
listString = listString .. element
end

return listString .. ', ' .. printTable(list, i + 1)

end

local table = {1, 2, 3, 4, 5, {'a', 'b'}, {'G', 'F'}}
print(printTable(table))

嗨，伙计，我用纯 Lua 编写了一个简单的代码，它有一个错误(在列表的最后一个元素之后写一个逗号)但是我如何快速将它作为原型编写，我会让它适应你它满足您的需求。

转成json再打印。

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local json = require('cjson')
json_string = json.encode(this_table)
print (json_string)

在 lua 中转储表的简单示例

我建议使用 serpent.lua

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local function parser(value, indent, subcategory)
local indent = indent or 2
local response = '(\
'
local subcategory = type(subcategory) == 'number' and subcategory or indent
for key, value in pairs(value) do
if type(value) == 'table' then
value = parser(value, indent, subcategory + indent)

elseif type(value) == 'string' then
value = '\''.. value .. '\''

elseif type(value) ~= 'number' then
value = tostring(value)
end

if type(tonumber(key)) == 'number' then
key = '[' .. key .. ']'
elseif not key:match('^([A-Za-z_][A-Za-z0-9_]*)$') then
key = '[\'' .. key .. '\']'
end
response = response .. string.rep(' ', subcategory) .. key .. ' = ' .. value .. ',\
'
end
return response .. string.rep(' ', subcategory - indent) .. ')'

end

示例

1 2	response = parser{1,2,3, {ok = 10, {}}} print(response)

结果

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(
[1] = 1,
[2] = 2,
[3] = 3,
[4] = (
[1] = (),
ok = 10
)
)

我已经谦虚地修改了一点 Alundaio 代码：

-- by Alundaio
-- KK modified 11/28/2019

function dump_table_to_string(node, tree, indentation)
local cache, stack, output = {},{},{}
local depth = 1

if type(node) ~="table" then
return"only table type is supported, got" .. type(node)
end

if nil == indentation then indentation = 1 end

local NEW_LINE ="\
"
local TAB_CHAR =""

if nil == tree then
NEW_LINE ="\
"
elseif not tree then
NEW_LINE =""
TAB_CHAR =""
end

local output_str ="{" .. NEW_LINE

while true do
local size = 0
for k,v in pairs(node) do
size = size + 1
end

local cur_index = 1
for k,v in pairs(node) do
if (cache[node] == nil) or (cur_index >= cache[node]) then

if (string.find(output_str,"}",output_str:len())) then
output_str = output_str .."," .. NEW_LINE
elseif not (string.find(output_str,NEW_LINE,output_str:len())) then
output_str = output_str .. NEW_LINE
end

-- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
table.insert(output,output_str)
output_str =""

local key
if (type(k) =="number" or type(k) =="boolean") then
key ="["..tostring(k).."]"
else
key ="['"..tostring(k).."']"
end

if (type(v) =="number" or type(v) =="boolean") then
output_str = output_str .. string.rep(TAB_CHAR,depth*indentation) .. key .." ="..tostring(v)
elseif (type(v) =="table") then
output_str = output_str .. string.rep(TAB_CHAR,depth*indentation) .. key .." = {" .. NEW_LINE
table.insert(stack,node)
table.insert(stack,v)
cache[node] = cur_index+1
break
else
output_str = output_str .. string.rep(TAB_CHAR,depth*indentation) .. key .." = '"..tostring(v).."'"
end

if (cur_index == size) then
output_str = output_str .. NEW_LINE .. string.rep(TAB_CHAR,(depth-1)*indentation) .."}"
else
output_str = output_str ..","
end
else
-- close the table
if (cur_index == size) then
output_str = output_str .. NEW_LINE .. string.rep(TAB_CHAR,(depth-1)*indentation) .."}"
end
end

cur_index = cur_index + 1
end

if (size == 0) then
output_str = output_str .. NEW_LINE .. string.rep(TAB_CHAR,(depth-1)*indentation) .."}"
end

if (#stack > 0) then
node = stack[#stack]
stack[#stack] = nil
depth = cache[node] == nil and depth + 1 or depth - 1
else
break
end
end

-- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
table.insert(output,output_str)
output_str = table.concat(output)

return output_str

end

然后：

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print(dump_table_to_string("AA", true,3))

print(dump_table_to_string({"AA","BB"}, true,3))

print(dump_table_to_string({"AA","BB"}))

print(dump_table_to_string({"AA","BB"},false))

print(dump_table_to_string({"AA","BB",{22,33}},true,2))

给予：

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only table type is supported, got string

{
[1] = 'AA',
[2] = 'BB'
}

{
[1] = 'AA',
[2] = 'BB'
}

{[1] = 'AA',[2] = 'BB'}

{
[1] = 'AA',
[2] = 'BB',
[3] = {
[1] = 22,
[2] = 33
}
}

现在函数 print 可以打印(平面)表格了！

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oprint = print -- origin print
print = function (...)
if type(...) =="table" then
local str = ''
local amount = 0
for i,v in pairs(...) do
amount=amount+1
local pre = type(i) =="string" and i.."=" or""
str = str .. pre..tostring(v) .."\\t"
end
oprint('#'..amount..':', str)
else
oprint(...)
end
end

例如：

1	print ({x=7, y=9, w=11, h="height", 7, 8, 9})

打印：

#7: 7 8 9 y=9 x=7 h=height w=11

同样的方法可以只是新函数tostring:

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otostring = tostring -- origin tostring
tostring = function (...)
if type(...) =="table" then
local str = '{'
for i,v in pairs(...) do
local pre = type(i) =="string" and i.."=" or""
str = str .. pre..tostring(v) ..","
end
str = str:sub(1, -3)
return str..'}'
else
return otostring(...)
end
end