Lua:仅在表中未添加或删除重复项时才添加到表的最聪明方法 [英] Lua: Smartest way to add to table only if not already in table, or remove duplicates

问题描述

我有一个字符串表.我想要一种简单的方法来删除表格的所有重复项.

I have a table of strings. I'd like an easy way to remove all of the duplicates of the table.

所以如果表是 {a, b, c, c, d, e, e} ，在这个操作之后它会是 {a, b, c, d, e}

So if the table is {a, b, c, c, d, e, e} , after this operation it would be {a, b, c, d, e}

或者，可能最好是有一种方法可以将元素添加到表格中，但前提是该元素尚未包含在表格中.

Alternatively, and probably preferably, is there a way to add an element to a table, but only if it is not already contained within the table.

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推荐答案

我通常为此做的是在字符串上索引表格，例如

What I normally do for this is index the table on the string so for example

tbl[mystring1] = 1
tbl[mystring2] = 1

等

当您添加字符串时，您只需使用上面的行，重复项将被处理.然后您可以使用 for ... 对 do 循环来读取数据.

When you add a string you simply use the lines above and duplicates will be taken care of. You can then use a for ... pairs do loop to read the data.

如果你想统计出现的次数

If you want to count the number of occurrences

使用类似

if tbl[mystring1] == nil then
  tbl[mystring1] = 1
else
  tbl[mystring1] = tbl[mystring1] + 1
end

作为加法循环的结束，如果你需要扭转局面，你可以简单地使用类似的东西

As the end of the addition cycle if you need to turn the table around you can simply use something like

newtbl = {}
for s,c in pairs(tbl) do
  table.insert(newtbl,s)
end

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