Better ways to convert tuple list to string

Question

I have a List in below structure:

Tuple<string, string>

like this:

And I would like to join the list to form a string like below:

['A', '1'],['B', '2'], ['C', '3']...

And I am now using below code to do:

string result = "";
for (int i = 0; i < list.Count; i++)
{
      result += "[ '" + list[i].Item1 + "', '" + list[i].Item2 + "'],";
}

The code works OK, but would like to ask if there're any better ways to do that?

Depends what you mean by "better". Certainly nothing that performs significantly better, unless you have millions of rows and decide to change to `StringBuilder`. — D Stanley, Jan 22 '16 at 04:22
Oh, I mean easier to read.. or this is already the simplest way to write..? — User2012384, Jan 22 '16 at 04:23
You could use `string.Format` and/or Linq, but neither of those are _huge_ improvements in my opinion. — D Stanley, Jan 22 '16 at 04:25
"Easier to read" is completely opinion based... Mine would be to use `String.Join(list, x=> String.Format("['{0}','{1}']", x.Item1, x.Item2)` to represent your exact code. But since I'm known string *escape* master :) I'd just use JSON serializer to avoid all "what if there is quote in one of the elements" issues. — Alexei Levenkov, Jan 22 '16 at 04:27
@AlexeiLevenkov I also want to use JSON serializer if possible... but unfortunately it isn't a json string — User2012384, Jan 22 '16 at 04:28

D Stanley · Accepted Answer · 2017-08-18T13:20:35.973

20

You can make it more compact by using Linq, string.Join and string.Format:

result = string.Join(",", list.Select(t => string.Format("[ '{0}', '{1}']", t.Item1, t.Item2)));

edited Aug 18 '17 at 13:20

answered Jan 22 '16 at 04:28

D Stanley

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Mine is better because 'x' > 't' :) – Alexei Levenkov Jan 22 '16 at 04:30
`t` as in `tuple` :) – D Stanley Jan 22 '16 at 13:42
Isn't there a typo inside the string.Format, currently the first parameter is t and it doesn't make sense – Franck Mesirard May 04 '17 at 07:30
Yes this is not correct. The is no string.Format(Tuple,string,int,int) method available.. – jimmious Aug 18 '17 at 08:20
@FranckMesirard Thanks, fixed. – D Stanley Aug 18 '17 at 13:20

score 9 · Answer 2 · answered Jan 22 '16 at 04:29

9

You can do it using linq and string interpolation like this:

string.Join(", ", list.Select(t => $"['{t.Item1}', '{t.Item2}']"));

answered Jan 22 '16 at 04:29

Arin Ghazarian

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score 2 · Answer 3 · edited May 23 '17 at 12:15

There are some benchmarking (note: each word contains one link, but one of the best reference I think is this.) on how to join the string.

Quote from the reference:

Rico Mariani, the .NET Performance guru, had an article on this very subject. It's not as simple as one might suspect.

You could take a look on string.Concat and string.Builder in particular, they are usually faster than + operator.

Here I use string.Concat:

string str = string.Concat(new string[] { "[ '", list[i].Item1, "', '", list[i].Item2, "']," });

score 2 · Answer 4 · answered Jan 22 '16 at 04:57

This might also do the trick for you

var input = new List<Tuple<string, string>> 
                { 
                    Tuple.Create("A", "1"), 
                    Tuple.Create("B", "2"), 
                    Tuple.Create("C", "3") 
                };
string tpljoined = string.Join(", ", 
                        input.Select(x => "['" + x.Item1 + "','" + x.Item2 + "']"));

score 1 · Answer 5 · answered Jan 22 '16 at 04:29

1

You can also use LINQ:

var input = new List<Tuple<string, string>> { Tuple.Create("A", "1"), Tuple.Create("B", "2") };
var result = String.Join(",", input.Select(elem => "[ '" + elem.Item1 + "', '" + elem.Item2 + "']"));
Console.WriteLine(result);

answered Jan 22 '16 at 04:29

w.b

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Better ways to convert tuple list to string

5 Answers5