Download a CSV of the constituents of the FTSE-100 from Yahoo Finance

http://uk.old.finance.yahoo.com/d/quotes.csv?s=@%5EFTSE&f=s&e=.csv

which(is.na(t.zoo[,2]))

which row has an NA value in the second column of variable t.zoo

Remove NA values

A<-na.omit(A)

Conditional array indexing in R

ts1[ts1[,6]>0,]

selects all rows of matrix “ts1″ that in column 6 have a value greater than zero. Don’t forget the very last comma!

Creating a generic container, and inner type, using Reflection

Type t = Type.GetType(outer_type);
if (t == null)
{
srt.LogClient.Log(Tools.LogLevel.Error, "Failed to instantiate type {0}", outer_type);
return;
}
if (t.IsGenericType == true)
{
Type[] innerTArr = t.GetGenericArguments();
if (innerTArr == null || innerTArr.Length == 0)
{
Log("inner Type was not found. Cannot instantiate a generic class");
return;
}

Type innerT = innerTArr[0];
Type genericType = t.GetGenericTypeDefinition();

Type[] typeArgs = { innerT };
Type constructed = genericType.MakeGenericType(typeArgs);
object o = Activator.CreateInstance(constructed);
mac = o as IMac;
}

Installing Windows Deployment Services on Server 2008 R2 for PXE Boot

Personal notes for performing this to install Windows 7 on a Toshiba R100, which has no DVD drive nor the ability to boot from USB.  These notes apply ONLY to Server 2008 R2, I believe some extra steps are required for 2008 R1 (which I haven’t tried, sorry)

1. Install WDS on a machine that is NOT hosting  DHCP server.  I used the DHCP on my router, which worked fine.
2. Download and install Windows Automated Install Toolkit (Windows AIK) ISO
3. Create a WinPE image using “copype x86 <dir>” for 32-bit, or “copype x64 <dir>” for 64-bit
4. Install the resulting boot image in the WDS install.
5. Boot your target machine, ensuring that it’s set to boot from PXE
6. Should now boot in to Windows PE – from here you can map a drive to a copy of the Windows 7 ISO/DVD, shared on another machine:
   net use Y: \\machine\share
7. CD to the Y: drive and run setup.exe

Group by date LINQ example

 var q = from t in _Trades
         let dt = t.TradeTime
         group t by new DateTime(dt.Year, dt.Month, dt.Day) into g
         select g;

         var dictionary = q.ToDictionary(result => result.Key, result => result.ToList());
			

Reflection snippet:

Type t = Type.GetType(kid.Attributes["type"].Value);
...
object o = t.Assembly.CreateInstance(t.FullName);


How to convert a string in ISO date format to a C# DateTime:

DateTime dt = DateTime.ParseExact(dateString, “yyyyMMdd”, CultureInfo.InvariantCulture);

Convert an integer in ISO format to a C# date

Yet another DateTime conversion routine, this time using DateTime.ParseExact()

int integerDate = "20081113";

DateTime date = DateTime.ParseExact(integerDate.ToString(), "yyyyMMdd", System.Globalization.CultureInfo.CurrentCulture);

A lovely piece of code for dealing with parameters in C#

I can’t claim credit for this, as I saw it yesterday whilst receiving a demo of a (very good) messaging architecture written by another developer.  It’s only a little scrap of code, but that makes it even better: its beauty is its simplicity.  So, to get parameters out of some parameter holding class, but to not have to (a) make everything the same type or; (b) have N methods for retrieving N types, you can do this:

    public class Params
    {
        Dictionary _values = new Dictionary();

        public Params()
        {
        }

        public T GetParam(string name, T defaultValue)
        {
            if (_values.ContainsKey(name) == false)
            {
                return defaultValue;
            }
            return (T)_values[name];
        }
     }

Which you then call like this:

            Params p = new Params();
            int key1 = p.GetParam("key1", 39);
            string key2 = p.GetParam("key2", "defaultValue");
            double key3 = p.GetParam("key3", 44.2);