Here's code that works, but is there a LINQ way to turn 2 line items into N based on quantity?
var list = new List<LineItem>{
new LineItem { Info = "two of these", Quantity = 2 },
new LineItem { Info = "one of these", Quantity = 1 }
};
// prints two lines
// 2x - two of these
// 1x - one of these
foreach( var entry in list) Console.WriteLine(entry);
Console.WriteLine("now I want three lines printed as for the shopping bag");
// prints threes lines quantity driving that
// 2x - two of these
// 2x - two of these
// 1x - one of these
// this works, but is there a clean LINQy way?
var bag = new List<LineItem>();
foreach( var item in list)
{
if ( item.Quantity == 1 )
bag.Add(item);
else
for ( var count = 0 ; count < item.Quantity ; ++ count)
bag.Add(item);
}
foreach( var entry in bag) Console.WriteLine(entry);
You can use a combination of SelectMany() and Enumerable.Repeat() to achieve what you want here. For example:
var list2 = list.SelectMany(x => Enumerable.Repeat(x, x.Quantity));
SelectMany() selects an element from each element x of the input. If any of these elements are sequences themselves, they are all flattened out into a single sequence (rather than say ending up with a list of lists)Enumerable.Repeat() creates a new enumerable based on each item, containing item x repeated x.Quantity times.Full listing as tested on .NetFiddle: https://dotnetfiddle.net/wpOafs
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public class LineItem
{
public string Info {get;set;}
public int Quantity {get;set;}
}
public static void Main()
{
var list = new List<LineItem>{
new LineItem { Info = "two of these", Quantity = 2 },
new LineItem { Info = "one of these", Quantity = 1 }
};
var list2 = list.SelectMany(x => Enumerable.Repeat(x, x.Quantity));
foreach(var item in list2)
{
Console.WriteLine(item.Info + item.Quantity);
}
Console.WriteLine("Hello World");
}
}