Tomas Petricek's blog

Writing about practical F# coding and programming language research

Visualizing interesting world facts with FsLab

In case you missed my recent official FsLab announcement, FsLab is a data-science package for .NET built around F# that makes it easy to get data using type providers, analyze them interactively (with great R integration) and visualize the results. You can find more on on, which also has links to some videos and download page with templates and other instructions.

Last time, I mentioned that we are working on integrating FsLab with the XPlot charting library. XPlot is a wonderful F# library built by Taha Hachana that wraps two powerful HTML5 visualization libraries - Google Charts and

I thought I'd see what interesting visualizations I can built with XPlot, so I opened the World Bank type provider to get some data about the world and Euro area, to make the blog post relevant to what is happening in the world today.

Published: Tuesday, 30 June 2015, 4:07 PM
Tags: f#, fslab, data science
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Recent articles from my blog

Against the definition of types

Thursday, 14 May 2015, 3:46 PM

What is the definition of type? Having a clear and precise answer to this question would avoid many misunderstandings but it would hurt science, 'hamper the growth of knowledge' and 'deflect the course of investigation into narrow channels of things already understood'.

Announcing FsLab: Data science package for Mono and .NET

Tuesday, 5 May 2015, 3:55 PM

After over a year of working on FsLab and talking about it at conferences, it is finally time for an official announcement. So, today, I'm excited to announce FsLab a cross-platform package for doing data science with .NET and Mono.

Comparing date range handling in C# and F#

Wednesday, 22 April 2015, 4:55 PM

I was recently working on some code for handling data ranges and I wrote initial version in C#. Later, I realized that I needed an F# version, so I went through the process of rewriting a simple function from C# to F#. This blog post compares the two versions.

Writing custom F# LINQ query builder

Tuesday, 7 April 2015, 1:41 PM

F# 3.0 provides full support for writing LINQ-style queries and the syntax can be used with SQL databases and many other standard data sources. But you can also write your own querying computation. This blog post shows a minimal example that shows how to parse F# queries and translate them to other querying language (like SQL).

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I'm an open-source developer and computer scientist who enjoys combining theory and practice. On the practical side, I write about F#, run trainings and provide consulting via fsharpWorks. On the theory side, I work on various programming language topics.

Trainings and consulting

I'm a frequent speaker at F# and .NET events, founding member of the F# Foundation author of C# and F# book and a StackOverflow fanatic. I have been Microsoft C# MVP since 2004 and used F# since early Microsoft Research versions.

Have you seen the F# testimonials and are you thinking how your company can also benefit from the safety, correctness, efficiency and faster time-to-market provided by F#?

Research & teaching

I'm interested in a wide range of topics in programming languages, ranging from category theory, comonads, reactive and distributed programming to scientific computing and working with data.

I like working on topics inspired by practical problems. I created a web framework for F# that inspired commercial projects like WebSharper and my experimental F# extensions can be tested live on

When the time permits, I enjoy traveling. The calendar shows a new picture each month. See 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 and the first photos of 2015.