Programming Blog

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

progblog — Mon, 09 Aug 2010 10:04:31 +0000

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

progblog — Fri, 23 Jul 2010 10:56:55 +0000

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

progblog — Fri, 23 Jul 2010 09:07:36 +0000

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

progblog — Wed, 26 May 2010 14:57:26 +0000

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

progblog — Sun, 23 May 2010 16:11:15 +0000

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)

Install WDS on a machine that is NOT hosting DHCP server. I used the DHCP on my router, which worked fine.
Download and install Windows Automated Install Toolkit (Windows AIK) ISO
Create a WinPE image using “copype x86 ” for 32-bit, or “copype x64 ” for 64-bit
Install the resulting boot image in the WDS install.
Boot your target machine, ensuring that it’s set to boot from PXE
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
CD to the Y: drive and run setup.exe

Group by date LINQ example

progblog — Wed, 28 Apr 2010 12:52:30 +0000

 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());

progblog — Wed, 04 Feb 2009 17:21:19 +0000

Reflection snippet:

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

progblog — Thu, 08 Jan 2009 18:09:27 +0000

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

progblog — Wed, 19 Nov 2008 12:02:44 +0000

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#

progblog — Tue, 07 Oct 2008 08:33:42 +0000

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);