LINQ表达式而不是嵌套的foreach循环

Question

So i have List whose each element is a string array

List<string[]> TokenList = new List<string[]>();

I want to display each element in the array for every array in the list. and for that i use a nested foreach loop.

foreach (var temp in pro.TokenList)
        {
            foreach (var s in temp)
            {
                Console.WriteLine(s);
            }
        }

Now i am trying to use LINQ in my programs and i was wondering what kind of LINQ query would be used to achieve the same desired result.

Answer 1

I'd rather keep it simple:

// select all sub-strings of each TokenList into 1 big IEnumerable.
var query = pro.TokenList.SelectMany(item => item);

// display all strings while iterating the query.
foreach(var s in query)
    Console.WriteLine(s);

It's funny that people combine many statements, but it will be less readable.

Answer 2

Console.WriteLine(String.Join(Environment.NewLine, 
    pro.TokenList.SelectMany(s => s)
));

Or,

Console.WriteLine(String.Join(Environment.NewLine, 
    from arr in pro.TokenList
    from s in arr
    select s
));

Answer 3

Try to do this:

Console.WriteLine(String.Join(Environment.NewLine, 
    pro.TokenList.SelectMany(s => s)
));

This should work. If it doesn't add a comment :)

Answer 4

pro.TokenList.ForEach(temp => Array.ForEach(temp, Console.WriteLine));  

但是，这里的LINQ并不多；），如注释中所述，只是更加简洁：)另外，正如Servy在另一个答案下指出的那样-这也具有不将所有字符串再次存储在内存中的优点。