Combining contents of 2 lists in C#
I just started learning C#. I want to combine 2 lists and return the output. For example:
List 1 = Peter, Tony, Steve
List 2 = Parker, Stark, Rogers
Final List/Output:
Peter Parker
Tony Stark
Steve Rogers
Here is my codes:
using System;
using System.Collections.Generic;
using System.Linq;
namespace HelloWorld
{
class Program
{
static void Main(string[] args)
{
var projectTeam = "Group Avengers";
Console.WriteLine("Avengers Assemble");
string[] firstNames = {"Peter", "Tony", "Steve"};
string[] lastNames = {"Parker", "Stark", "Rogers"};
IList<string> combinedNames = new List<string>();
foreach (string firstName in firstNames)
{
foreach (string lastName in lastNames)
{
Console.WriteLine(firstName + lastName);
}
}
}
}
}
Actual Output:
Avengers Assemble
PeterParker
PeterStark
PeterRogers
TonyParker
TonyStark
TonyRogers
SteveParker
SteveStark
SteveRogers
Expected Output:
Avengers Assemble
Peter Parker
Tony Stark
Steve Rogers
Solution 1:
You could use a for
-loop and access the lists via index:
for(int i = 0; i < Math.Min(firstNames.Length, lastNames.Length); i++)
{
Console.WriteLine(firstNames[i] + lastNames[i]);
}
better would it be to store the two related information in a common class, for example Avenger
with properties FirstName
and LastName
.
Another way to link two related lists is LINQ's Zip
:
var zippedAvengers = firstNames.Zip(lastNames, (f,l) => f + " " + l);
foreach(string name in zippedAvengers)
Console.WriteLine(name);
Solution 2:
In your code you need only one loop and it should be for
, not foreach
for (var i = 0; i< firstNames.Length; i++)
{
string firstName = firstNames[i];
string lastName = lastNames[i];
Console.WriteLine(firstName + lastName);
}
You can also replace this with IEnumerable.Zip
(https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.zip?view=net-6.0)
firstNames
.Zip(lastNames, (first, last) => first + last)
.ToList()
.ForEach(x=>Console.WriteLine(x));
Please note that both approaches assumes that both firstNames
and lastNames
has the same number of elements.
Solution 3:
If you alter the loop:
for (int i=0; i < firstNames.Count; i++)
{
Console.WriteLine(firstNames[i] + " " + lastNames[i]);
}
It'll work.
As a side note - in newer versions on .NET you can simplify the concatenation with $"{firstNames[i]} {lastNames[i]}"
Plus, the .Zip solution (as proposed by Serg):
firstNames
.Zip(lastNames, (first, last) => first + " " + last)
.ToList()
.ForEach(x=>Console.WriteLine(x));
Would be more efficient
Solution 4:
What you are doing is you're matching every element of the first list with every element of the second list. But what you wanna do, if I get you right, is to match the first element of the first list with the first element of the second list.
In order to do that, I won't give you the code so you can learn but I can show you where to go :
- Make sure your lists are both the same size, otherwise you will get an exception trying to access an inexisting index
- Use
for
loop instead offoreach
, they are less instinctive but more useful in this situation. For each index of the two lists, make the same index of the third list (the result) correspond to the concatenation of the two, for example :
result[0] = firstList[0] + secondList[0];
(In order to have a space between the two, you must add a space between the first and the second list item)