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C# Split text array into sub array

I can't seem to find much on this online :(
For my course I have to get text from a grocery.txt file and output an invoice.
The text file looks like this:
regular,bread,2.00,2
regular,milk,2.00,3
regular,cereal,4.00,1
fresh,rump steak,11.99,0.8
fresh,apple,4.60,1.00
fresh,cucumber,2.20,0.936
regular,cream,2.20,1
regular,mustard,3.30,1
fresh,carrots,1.79,1.5
regular,tomato sauce,2.95,1
regular,salt,2.80,1
fresh,bananas,4.00,1.2
Currently I use this method to get the text:
string[] groceryItemsArray = System.IO.File.ReadAllLines(#"C:\C\groceries.txt");
What I get is an array that in stores the entire line (for example "fresh,bananas,4.00,1.2").
I have no idea how to split the array into sub arrays or even whats the best way to go about this. Unfortunately this course task are way too advanced for the little material we have been taught and time we have for this. I have already spend around 6 hours watching videos and getting not very far in learning the advanced stuff.
This is what I am trying to accomplish.
A. Class named grocerrItem. This class has properties:
name and price
this class must have 2 constructors
A. subclass of this is a purchasedItem.
this class has an integer property 'quantity'
one of its methods findCost, calculates the cost of the item, including 10% GST.
the formula for this is price * quantity * 1.1
C. A subclass of this class (purchasedItem), freshItem has
a property weight, a double type.
The findCost method here, uses the formula:wieght * price, as it is not subject to GST.
Groceries.txt contains information as follows:
type(regular or fresh), name, price, quantity/weight - depending on being regular or fresh.
** An invoice should be represented as a collection of grocery items (parent class). This can be done using any container structure i.e. array, list or collection. you will then use iteration

You can just use String.Split which returns you the sub array that you want.
public static void Main()
{
string[] groceryItemsArray = System.IO.File.ReadAllLines(#"C:\C\groceries.txt");
// now split each line content with comma. It'll return you an array (sub-array)
foreach (var line in groceryItemsArray)
{
string[] itemsInLine = line.Split(',');
// Do whatevery you want to do with this.
// e.g. for 1st line itemsInLine array will contains 4 items
// "regular","bread","2.00", "2"
}
}

You can use this code (I'm not sure what exactly you looking for):
/// It's return all text as a single list
var groceryItemsArray = System.IO.File.ReadAllLines(#"C:\C\groceries.txt")
.SelectMany(x => x.Split(new char[]{','} , StringSplitOptions.RemoveEmptyEntries)).ToList() ;
Or if want to return as Child List can use this code:
var groceryItemsArray = System.IO.File.ReadAllLines(#"C:\C\groceries.txt").Select(x =>
new { Child = x.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries) }).ToList();

I didn't really understand what are you trying to output, but here's some basic things I did understand on your question:
(code not tested)
I created a parent class:
class GroceryItem
{
public string ItemName {get;set;}
public decimal Price {get;set;}
public GroceryItem() { }
}
And creates a child class:
class PurchasedItem : GroceryItem
{
public int Quantity { get;set; }
public decimal Cost { get;set; }
public PurchasedItem(string[] item)
{
ItemName = item[1];
Price = decimal.Parse(item[2]);
Quantity = int.Parse(item[3]);
FindCost();
}
private void FindCost()
{
Cost = Price * Quantity * 1.1;
}
}
Using your input to get all groceryItems, you can iterate using foreach loop and collect a list of purchasedItems.
Main()
{
string[] groceryItems = System.IO.File.ReadAllLines(#"C:\C\groceries.txt");
var purchasedItems = new List<PurchasedItem>();
foreach (var item in groceryItems)
{
string[] line = item.Split(',');
purchasedItems.Add(new PurchasedItem(line));
}
}
Well if you didn't understand this basic concept of programming, you better start on this link.

How to implement a SearchByID?

Good afternoon all!
As a part of getting a better grip on some of the most aspects of object based programming, I've started to attempt something far larger than I have done in the past. Hereby I'm trying to learn about inheritance, code reuse, using classes far more extensively, and so on.
For this purpose I am trying to piece together all the parts required for a basic RPG/dungeon crawler.
I know this has been done a billion times before, but I find that actually trying to code something like it takes you through a lot more problems than you might think, which is a great way to learn (I think).
For now I have only loaded up a WPF application, since my interest is 95% on being able to piece together the working classes, routines, functions, etc. And not so much interested in how it will look. I am actually reading up on XNA, but since I am mostly trying to get a grip on the basic workings, I don't want to complicate those aspects with the graphical side of things just yet.
The problem I am now facing is that when I would a character to attack or defend, it should know from which other character it came, or to which one it should be pointed. I figured I could either use a GUID, or a manually appointed ID. But the problem is that I don't really know how I can implement such a thing.
The thing that I figured was that I could maybe add a reference to an array (Character[]), and have a SearchByID function loop through them to find the right one, and return it. Like so:
internal Character SearchByID(string _ID)
{
foreach(Character charToFind in Character[])
{
if(charToFind.ID == _ID)
return charToFind;
}
}
This of course has to be altered a bit due to the return at the moment, but just to give you an idea.
What I am stuck on is how to create the appropriate array outside of the "Character"-class? I can fill it up just fine, but how do I go about having it added above class level?
The way the "Character"-class is built up is that every new character instantiates from the Character class. The constructor then loads the appropriate values. But other than this, I see no possibility to initialize an array outside of this.
If it is preferable to post the entire code that I have, that will be no problem at all!
Thanks for any insights you may provide me with.

I think you can just use the Character-class and pass other Characters to it, for example:
public class Character
{
public string Name { get; private set; }
public int HitPoints { get; private set; }
public int Offense { get; private set; }
public int Defense { get; private set; }
public Character(string name, int hitPoints, int offense, int defense)
{
Name = name;
HitPoints = hitPoints;
Offense = offense;
Defense = defense;
}
public void Defend(Character source)
{
HitPoints = HitPoints - (source.Offense - Defense);
if (HitPoints <= 0)
{
Console.WriteLine("{0} died", Name);
}
}
public void Attack(Character target)
{
// Here you can call the other character's defend with this char as an attacker
target.Defend(this);
if (target.HitPoints <= 0)
{
Console.WriteLine("{0} killed {1}", Name, target.Name);
}
}
}
The thing with object oriented programming is that you have to start thinking in objects. Objects are like boxes when they're concrete. You can make new ones and give them some properties, like a name, height, width, hitpoints, whatever. You can also let these objects perform actions. Now a simple box won't do much itself, but a character can do various things, so it makes sense to put these actions in the Character-class.
Besides having Characters, you might have a Game-class which manages the game-state, characters, monsters, treasure chests etc...
Now this simple example may cause you to gain HitPoints when your defense is higher than the attacker's offense, but that's details, I'll leave the exact implementation up to you.

I guess you want a way to insert characters in an array when they are instantiated..
You can make a static array or list
So,your class in my opinion should be
class Character
{
static List<Character> characterList=new List<Character>();//all characters are here
public Character(string id,...)
{
//initialize your object
characterList.Add(this);//store them in the list as and when created
}
internal Character SearchByID(string _ID)
{
foreach(Character charToFind in characterList)
{
if(charToFind.ID == _ID)
return charToFind;
}
}
}
As you may be knowing static members are associated with the class not with the object.So,when you create a new character object it would be automatically added to the characterList

Unless you are dealing with seperate processes, e.g. client-server, you probably don't want to use "Id"s at all.
Whereever you are passing string _ID around, pass the actual Character instead. This saves you looking up in an array or whatever.
Post more code, and I can show you what I mean.

You could use a dictionary, instantiated in your controller class:
Dictionary<Guid, Character> _characterList = new Dictionary<Guid, Character>();
Initialise:
var someCharacter = new Character() { stats = something };
var otherCharacter = new Character() { stats = anotherThing };
var char1Id = Guid.NewGuid();
var char2Id = Guid.NewGuid();
_characterList.Add(char1Id, someCharacter);
_characterList.Add(char2Id, otherCharacter);
then, to access characters:
var charToFind = _characterList[char1Id];
or
var charToFind = _characterList.Single(c => c.Name = "Fred The Killer");
or whatever else...

Check out keyed collection
KeyedCollection
It is like a dictionary where the key is a property of class.
You will be able to reference a Character with
Characters[id]
Syntax
On your Character class overrite GetHashCode and Equals for performance.
If you use Int32 for the ID then you will get a perfect hash.
Very fast and O(1).

Naming a variable from a text file

I'm making a program in C# that uses mathematical sets of numbers. I've defined the class Conjunto (which means "set" in spanish). Conjunto has an ArrayList that contains all the numbers of the set. It also has a string called "ID" which is pretty much what it sounds; the name of an instance of Conjunto.
The program have methods that applies the operations of union, intersection, etc, between the sets.
Everything was fine, but now i've a text file with sentences like:
A={1,2,3}
B={2,4,5}
A intersection B
B union A
And so on. The thing is, i don't know how many sets the text file contains, and i don't know how to name the variables after those sentences. For example, name an instance of Conjunto A, and name another instance B.
Sorry for the grammar, english is not my native language.
Thanks!

It's pretty complicated to create varaibles dynamically, and pretty useless unless you have some already existing code that expects certain variables.
Use a Dictionary<string, Conjunto> to hold your instances of the class. That way you can access them by name.

First off, If you don't target lower version than .Net 2.0 use List instead of ArrayList. If I were you I wouldn't reinvent the wheel. Use HashSet or SortedSet to store the numbers and then you can use defined union and intersection.
Secondly, what is your goal? Do want to have just the output set after all operations? Do you want to read and store all actions and them process it on some event?

First of all, your program is taken from bad side. I would advice to start making new one. One of ways to name "variables" dynamicaly is by making class objects and editing their properties.
This is what I made as a starting platform:
First af all I have crated a class called set
class set
{
public string ID { get; set; }
public List<int> numbers { get; set; }
}
Then I have made the code to sort whole textfile into list of those classes:
List<set> Sets = new List<set>();
string textfile = "your text file";
char[] spliter = new char[] { ',' }; //switch that , to whatever you want but this will split whole textfile into fragments of sets
List<string> files = textfile.Split(spliter).ToList<string>();
int i = 1;
foreach (string file in files)
{
set set = new set();
set.ID = i.ToString();
char[] secondspliter = new char[] { ',' }; //switch that , to whatever you want but this will split one set into lone numbers
List<string> data = textfile.Split(secondspliter).ToList<string>();
foreach (string number in data)
{
bool success = Int32.TryParse(number, out int outcome);
if (success)
{
set.numbers.Add(outcome);
}
}
i++;
Sets.Add(set);
}
Hope it helps someone.

c# Memory performance and speedup

i have a situation, i need to process an jagged array of 20k registers every time a user press a key. I have a grid and while the user is typing the system shows a filtered result in a grid. so. So i have a jagged array filled with all 20k registers. and the i have a list (global to the control) and it´s cleaned up every time the user press a key and filled up with just the filtered registers and then show then in the grid.
Here is the code
the model
public struct PlayerLookUpAdapter
{
[Browsable(false)]
public decimal Id { get; set; }
[DisplayName("Número")]
public String Number { get; set; }
[DisplayName("Nombre")]
public String Name { get; set; }
[DisplayName("Apellido")]
public String Surname { get; set; }
[DisplayName("DNI")]
public String Document { get; set; }
[DisplayName("Estado")]
public String Status { get; set; }
}
private PlayerLookUpAdapter[] _source; // here are the 20k registers
List<PlayerLookUpAdapter> filteredOut = new List<PlayerLookUpAdapter>(); // here the filtered ones
// this code is executed every time the user press a key
private void tb_nro_KeyUp(object sender, KeyEventArgs e)
{
if (!(e.KeyCode.Equals(Keys.Enter) || e.KeyCode.Equals(Keys.Down)) && _source!=null)
{
String text = tb_nro.Text.ToUpper();
if (String.IsNullOrEmpty(text))
{
fg.DataSource = _source;
fg.Refresh();
return;
}
fg.DataSource = null;
filteredOut.Clear();
int length = _source.Length;
for (int i = 0; i < length; i++)
{
PlayerLookUpAdapter cur = _source[i];
if (cur.Number.ToUpper().StartsWith(text) || cur.Surname.ToUpper().StartsWith(text) || cur.Name.ToUpper().StartsWith(text))
filteredOut.Add(cur);
}
fg.DataSource = filteredOut;
SetGridColumnsProperties();
fg.Refresh();
}
else
{
fg.Focus();
}
}
is it a good solution in terms of memory usage and performance? have you got any advice? How can i gain more speed. It works realy good, but what about if i got 100k registers instead of 20k?
Thanks in advance.

I think this should be a prime example for using a tree.
If you lay your Data down in a Tree (i actually don't know if C#/.Net supports a Tree Data-Structure, or you have get your own hands dirty).
The Speed you search in a Tree will increase in comparison for searching in an Array (because a Tree gots a search-speed of somehting like O(n)=n*log(n))
The Theory is easy: if a User Types in a Literal, the Tree goes to the Node starting with this Literal, on this nodes are all possible other nodes and so on. For example: The User types in an "t" you go to the "t" Node, then he types in an "e" you go to the subnode "te", there are some other subnodes like "test" and the system will propose the User these subnodes.

firts of all you could improve a bit your code: the StartWith method has an overload who takes the string comparison as well. you could set it as "OrdinalIgnoreCase" to avoid to upper all the strings but I don't think you will gain a lot.
The only way you have to speed up you search is go for a Search engine as Lucene.net.
http://www.codeproject.com/KB/library/IntroducingLucene.aspx

You want a prefix tree for this.
Here is one implementation:
A Reusable Prefix Tree using Generics in C# 2.0

You could probably use the StringComparison.OrdinalIgnoreCase option on your string comparisons and avoid having to call ToUpper on all your strings 20k times.
Ideally, first you need to decide how slow is too slow based on your best estimates for typical usage of your program. After all premature optimisation is the root of all evil.

Precalculate the ToUpper() call so you dont have to do it every time. You could maintain a second list where all the strings are stored uppercase.
Secondly you should search the filtered list (instead of the whole list) in case a key is added to the search string. The new (longer) string can never be outside of the filtered results.

Replacement of enum that requires translation and enumeration

We have some stuff that may be exported into various formats. Currently we have these formats represented by an enum like this:
[Flags]
public enum ExportFormat
{
None = 0x0,
Csv = 0x1,
Tsv = 0x2,
Excel = 0x4,
All = Excel | Csv | Tsv
}
Problem is that these must be enumerated and they also need a translation or description in the ui. Currently I solved this by creating two extension methods. They work, but I don't really like them or the solution at all... they feel kind of smelly. Problem is I don't really know how I could do this better. Does anyone have any good alternatives? These are the two methods:
public static IEnumerable<ExportFormat> Formats(this ExportFormat exportFormats)
{
foreach (ExportFormat e in Enum.GetValues(typeof (ExportFormat)))
{
if (e == ExportFormat.None || e == ExportFormat.All)
continue;
if ((exportFormats & e) == e)
yield return e;
}
}
public static string Describe(this ExportFormat e)
{
var r = new List<string>();
if ((e & ExportFormat.Csv) == ExportFormat.Csv)
r.Add("Comma Separated Values");
if ((e & ExportFormat.Tsv) == ExportFormat.Tsv)
r.Add("Tab Separated Values");
if ((e & ExportFormat.Excel) == ExportFormat.Excel)
r.Add("Microsoft Excel 2007");
return r.Join(", ");
}
Maybe this is the way to do this, but I have a feeling there must be better ways to do it. How could I refactor this?

You could use the Formats method inside Describe to avoid doing all the bit operations at multiple places, like this:
private static Dictionary<ExportFormat, string> FormatDescriptions =
new Dictionary<ExportFormat,string>()
{
{ ExportFormat.Csv, "Comma Separated Values" },
{ ExportFormat.Tsv, "Tab Separated Values" },
{ ExportFormat.Excel, "Microsoft Excel 2007" },
};
public static string Describe(this ExportFormat e)
{
var formats = e.Formats();
var descriptions = formats.Select(fmt => FormatDescriptions[fmt]);
return string.Join(", ", descriptions.ToArray());
}
This way, it is easy to incorporate the string descriptions from an external source or localization, as hinted above.

The only other way comes to my mind is the usage of the System.Attribute class.
public class FormatDescription : Attribute
{
public string Description { get; private set; }
public FormatDescription(string description)
{
Description = description;
}
}
And then use Reflection with in your Describe function.
The only benefit of this method would be to have definition and the description at one place.

Dupe: How do I have an enum bound combobox with custom string formatting for enum values?
You could write an TypeConverter that reads specified attributes to look them up in your resources. Thus you would get multi-language support for display names without much hastle.
Look into the TypeConverter's ConvertFrom/ConvertTo methods, and use reflection to read attributes on your enum fields.
Addition:
Scroll down in the linked post for a implementation of a TypeConverter that does part of what is required for full support.
This would support an application where you have several languages at the same time, not only code name -> english name.
Remember that this is only the display name, never the stored value. You should always store the code name, or the integer value, to support users with different locales using the same data.