我们如何更改打印显示表格的方式 [英] How do we change the way print displays a table

问题描述

假设我有一段代码，如下所示

Assuming I have a piece of code such as the following

aTable = {aValue=1}
aTable_mt = {}
print(aTable)  

我该怎么做才能使Lua打印类似aTable current aValue = 1而不是table: 0x01ab1d2的内容.

What must I do to make Lua print something like aTable current aValue = 1 as opposed to table: 0x01ab1d2.

到目前为止，我已经尝试设置__tostring元方法，但是print似乎并未调用该方法.是否有我缺少的元方法，或者答案与元方法无关?

So far I've tried setting the __tostring metamethod but that doesn't seem to be invoked by print. Is there some metamethod I've been missing or does the answer have nothing to do with metamethods?

推荐答案

__tostring可行:

aTable = {aValue=1}
local mt = {__tostring = function(t) 
                           local result = ''
                           for k, v in pairs(t) do
                             result = result .. tostring(k) .. ' ' .. tostring(v) .. ''
                           end
                           return result
                         end}      

setmetatable(aTable, mt)    

print(aTable) 

这将打印aValue 1(带有一个额外的空格，请以真实代码将其删除). aTable部分不可用，因为aTable是引用表的变量，而不是表本身的内容.

This prints aValue 1 (with one extra whitespace, remove it in real code). The aTable part is not available, because aTable is a variable that references the table, not the content of the table itself.

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