How to loop two c# List parallelly

Sujeet Raman

Hi,

I have two lists - list1 and list2. i want to concatinate list 1 item + list 2 item and save to txt file.below code is not working how we can loop parellely?

foreach (string code in List1)
{
    for (int i = 0; i < List2.Count; i++)
    {
        if (code != "")
        {
            string total = code + ", " + "'" + List2[i] + "')";
            fullcode.Add(total);
        }
    }
}

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Muhammad Imran Ansari4y ago
Accepted answer
Check the following code:
List<string> list1 = new List<string>() { "hello", "hai", "how", "hey" };
List<string> list2 = new List<string>() { "bro", "joy", "sam", "don" };

if (list1.Count == list2.Count)
{
    string data = "";
    for (int i = 0; i < list1.Count; i++)
    {
        data += list1[i] + " " + list2[i] + ",";
    }
    // To remove last ','
    data = data.Substring(0, data.Length - 1);
    // TODO Save data into file
}
else
{
    Console.WriteLine("Both lists have identical items.");
}
Sachin Singh4y ago
Use union
var finalList= List1.Union(List2).ToList();
var chunks=finalList.Select((x, i) => new { Index = i, Value = x })
        .GroupBy(x => x.Index / 2)
        .Select(x => x.Select(v => v.Value).ToList())
        .ToList();

foreach(var item in chunks)
{

foreach (var grp in item)
{
grp

}




}
Sujeet Raman4y ago
sorry i didnt get.. can u show me a sample
Nitin Sontakke4y ago
Okay. Got it. First make sure that both list have identical number of items.
If not then device and implement the error handling strategy.

Then have second list converted to an array.

Traverse the first list and pad corrosponding array location value created from second list.

Hope it clarifies.
Sujeet Raman4y ago
List1
........

hello
hai
how
hey

List1
........

bro
joy
sam
don

expecting-hello bro,hai joy
Nitin Sontakke4y ago
May be you should post some sample data and expected output.

Also considering sample data, what out put you are getting with above.

One suggestion. You can short circuit the foreach loop if code is empty. Check it immediately and continue the code if such is the case.