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
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);
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://learn.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.
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
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 of foreach, 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)
This can be done with LINQ Zip():
var fullNames = firstNames.Zip(lastNames, (first, last) => $"{first} {last}")
Zip takes the two lists and runs through both of them simultaneously, applying the function to each pair.
You are running two for loops for no reason. Just run one single loop from i = 0 to i = 3(not included).Then you can pick the ith element from both the lists.
Example. for i = 0, firstNames[0] = "Peter" lastNames[0] = "Parker"
You can print
Console.WriteLine(firstNames[i] + " " + lastNames[i]);
Related
so bassicly I've got 2 different List
List<string> result = new List<string>;
List<string> outputs= new List<string>;
the outputs List getting filled in an loop and after the loop ends it will add the outputs list in the result list.
So that outputs will have this different values after the loop ends.
For example after the first loop ends the output list has data like:
exampleData1
exampleData2
exampleData3
and so on
so that the result List would now have this three example data.
Now the loop will hit again and will load different data like:
exampleData1.1
exampleData2.1
exampleData3.1
and now It should add this three example data to the result list:
so that now the result list should look like that:
exampleData1, exampleData1.1
exampleData2, exampleData2.1
exampleData3, exampleData3.1
and so should It go on after each loop after the output list changed it should be add side by side like one string.
I have tried things like that:
foreach (var (item1, item2) in output.Zip(output, (xo, y) => (xo, y)))
result.Add($" {item1}, {item2}");
but that's only adding the existing list side by side so that I have 2x the same value side by side.
I hope I have explained it understandable and if not, pls let me know.
Zip is good idea, but care. From the documentation :
If the sequences do not have the same number of elements, the method merges sequences until it reaches the end of one of them.
As result is empty, the end is reached before to start. The solution is to complete with the elements not iterated by Zip :
result = result.Zip(outputs, (r, o) => r + ", " + o)
.Union(result.Skip(outputs.Count)) // Add element from result not iterated by Zip
.Union(outputs.Skip(result.Count)) // Add element from outputs not iterated by Zip
.ToList();
Have look at this: https://learn.microsoft.com/en-us/dotnet/api/system.linq.enumerable.zip?view=net-7.0 I think you have a mistake in your code. You're "zipping" outputs with outputs (i.e. itself) you need to zip it with result.
var mergedLists = result.Zip(outputs, (first, second) => first + " " + second);
UPDATED
Here's a full console app solution:
List<string> result = new();
for (var i = 0; i < 3; i++)
{
List<string> outputs = new();
for (var j = 0; j < 3; j++)
{
outputs.Add($"TestData{i}.{j}");
}
if (!result.Any())
{
result = outputs.ToList();
}
else
{
result = result.Zip(outputs, (first, second) => first + " " + second).ToList();
}
}
Console.WriteLine(string.Join(Environment.NewLine, result));
Console.ReadLine();
I am trying unsuccessfully to change the following loop to a LINQ expression:
int index = 0;
IList<IWebElement> divNota = new List<IWebElement>();
foreach (IWebElement element in tablaNotas)
{
divNota.Add(element.FindElement(By.Id("accion-1-celda-0-" + index + "-0")));
index++;
}
I tried using
IList <IWebElement> divNota = tablaNotas.Select(element => element.FindElement(By.Id("accion-1-celda-0-"+ tablaNotas.IndexOf(element) + "-0"))).ToList();
But tablaNotas.IndexOf(element)always returns -1, meaning the element was not found inside tablaNotas.
The string "accion-1-celda-0-"+ tablaNotas.IndexOf(element) + "-0" is meant to change to
"accion-1-celda-0-"+ 1 + "-0"
"accion-1-celda-0-"+ 2 + "-0"
"accion-1-celda-0-"+ 3 + "-0"
...
"accion-1-celda-0-"+ n + "-0"
In accordance to element's index
Any help is appreciated
In Linq some reserved word like Where, FirstOrDefault create a condition for your query and the Select reserved word can create your object that you want the Select method applies a method to elements. It is an elegant way to modify the elements in a collection such as an array. This method receives as a parameter an anonymous function—typically specified as a lambda expression.
Example: Let's look at a program where the Select extension method is applied to a string array. A local variable of array type is allocated and three string literals are used. We use Select on this array reference.
The basic method are here:
public static System.Collections.Generic.IEnumerable<TResult> Select<TSource,TResult> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,int,TResult> selector);
Now! for this issue that you searched for that you can use of this code:
var divNotaResult = list
.Select((data, index) => data.FindElement(By.Id("accion-1-celda-0-" + index + "-0")))
.ToList();
In Select method do like foreach we have tow object in function data and index.
The data have each data in loop, and the index have count of loop.
var result = tableNotas
.Select((element, index) => element.FindElement(By.Id("accion-1-celda-0-" + index + "-0")))
.ToList();
Use this:
var divNota =
tablaNotas.Select((element, index) =>
element.FindElement(By.Id($"accion-1-celda-0-{index}-0")))
.ToList();
I am new to Linq..
i have List<string> object in my code.. i wanted to make it comma separeted, so i written following syntax
string commaSepNames = string.Join(",",lstNames.select(s=>s+" Customer").ToList());
The above syntax will result in appends with "Customer" in the end of name
with comma separated...
but now i want to Append Number (from 1 to Number of item in List) at the end of "Customer" like following:
John Customer1,
Ghanshyam Customer2,
Ferry Customer3,
... and so on..
how can i achive it in one Syntax line ? without using "for loop" or "foreach loop" ??
Thanks....
Use the overload of Enumerable.Select that gives you the index:
var names = lstNames.Select((s, index) => string.Format("{0} Customer{1}", s, index + 1));
string commaSepNames = string.Join(",", names);
If you are not using .NET 4 you need an array:
string commaSepNames = string.Join(",", names.ToArray());
I'm after some help with how to query a list and return back the index, but not using Linq. I've seen many example where Linq is used, but the software I'm writing the query into doesn't support Linq. :(
So example to get us going:
List<string> location = new List<string>();
location.add(#"C:\test\numbers\FileName_IgnoreThis_1.jpg");
location.add(#"C:\test\numbers\FileName_IgnoreThis_2.jpg");
location.add(#"C:\test\numbers\FileName_ImAfterThis_3.jpg");
location.add(#"C:\test\numbers\FileName_IgnoreThis_4.jpg");
location.add(#"C:\test\numbers\FileName_ImAfterThis_5.jpg");
So this list will be populated with probably a few hundred records, what I need to do is query the list for the text "ImAfterThis" then return the index number location for this item into a string array but without using Linq.
The desired result would be 2 and 4 being added to the string array.
I was thinking of doing a for loop through the list, but is there a better way to achieve this?
List<int> results = new List<int>();
int i = 0;
foreach (string value in location)
{
if (value.Contains("IAfterThis"))
{
results.Add(i);
Console.WriteLine("Found in Index: " + i);
}
i++;
}
Console.ReadLine();
Thanks in advance.
If you want to get just the first occurrence you could simply use the IndexOf() method.
If you want all occurrences of string "whatever" then a for loop would certainly work for you. For the sake of argument here I've capture the indexes in another list:
string MyString = "whatever";
List<int> indexes = new List();
for (int i = 0; i < location.Count; i++)
{
if (location[i] == MyString)
{
indexes.Add(i);
}
}
I want to know the quickest and simplest way to sort the code shown below. Sorting from newRecord.AppCode would not be suitable as it will change the meaning of the output. So I need to sort every line from string outp. What would be the best way? Also I would like to make every row distinct. I beleive using LINQ would be very quick but I am not that great at it. Help appreciated. So close to getting it done! Note: Data is being pulled from a tsv. Using .net 3.5, visual studio 2008) Will mark answer as soon as I get progress. :)
while ((line = sr.ReadLine()) != null)
{
String[] splitted = line.Split('\t');
appcodes.Add(line);
Records newRecord = new Records();
newRecord.Server = splitted[0];
newRecord.Instance = splitted[1];
newRecord.AppCode = splitted[2];
newRecord.Database = splitted[3];
listrecords.Add(newRecord);
for (int i = 0; i < appcodes.Count(); i++)
{
if (newRecord.AppCode==appcodes[i].ToUpper())
{
String outp = newRecord.AppCode + " " + newRecord.Server + " " + newRecord.Instance + " " + newRecord.Database;
Console.WriteLine(outp);
}
}
}
have lists named Keepers and newkeepers. Was trying to do something like outp.sort() and outp.sort() but it doesnt work in strings. This is how I solved the problem.
Keepers.Add(outp);
Keepers.Sort();
newKeepers = Keepers.Distinct().ToList();
foreach (object o in newKeepers)
{
Console.WriteLine(o);
}
Console.ReadLine();
As you can see, newrecords contain different fields so I wrote a LINQ statement to solve the problem.
var sorted_list = (from r in newrecords
orderby r.AppCode, r.Server, r.Instance, r.Database
select r).Distinct().ToList();
var distinctSortedList = sorted_list.Distinct().ToList();