Linq with jagged arrays

Question

User-382098719 posted

I am trying to understand a piece of code but I am not sure I do. I will be very grateful if someone could explain to me what happens here:

foreach (var row in jaggedArray.Skip(1).OrderBy(r => r[headerIndex]))
{
    Console.WriteLine(string.Join(" | ", row));
}

I suggest that .Skip(1) misses the first row, but after that, I did not understand anything. I will give you an example of what this code does:

4
name, age, grade
Peter, 25, 5.00
George, 34, 6.00
Marry, 28, 5.49
sort name

This is an example input. Our jagged array has 4 rows and 3 columns. We have to sort the name header so in this case, the header index is equal to 0. Thank you advance!

Answer 1

User753101303 posted

Hi,

String.Join is to concatenate all values taken from an array with the given separator..It should output something such as :

Peter | 25 | 5.00
George | 34 | 6.00
Marry | 28 | 5.49

(seems easy to create a console app to test that with the exact input parameters you want). Edit: forgot the sort, the ordering is likely George, Marry, and Peter...

Edit2: while I'm at it you could just test yourself what yoou get with a test console app such as :

using System;
using System.Linq;
namespace ConsoleDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            string[][] jaggedArray = {
                new string[]{"name", "age", "grade"},
                new string[] { "Peter", "25", "5.00" },
                new string[] { "George", "34", "6.00" },
                new string[]{"Marry", "28", "5.49"} };
            const int headerIndex = 0;
            foreach (var row in jaggedArray.Skip(1).OrderBy(r => r[headerIndex]))
            {
                Console.WriteLine(string.Join(" | ", row));
            }
        }
    }
}

Answer 2

User-1764593085 posted

Hi kaloyan,

Since it is jaggedArray, then `row` is a string[] variable in the foreach loop which corresponds to each row of the jaggedArray.

Use OrderBy(r=>r[columnIndex]) to sort the specific column, refer to here.In the case, it will sort name column by initials.

Use String.Join(String separator, params String[] value); to concatenates the elements of a string array, using the specified separator between each element, refer to here. In the case, it return the  Peter | 25 | 5.00