Wednesday, December 11, 2013

F# - even the longest journey begins with a single step. And there may be bumps along the way

Don't take me wrong. I have just started familiarizing myself with F# - a fairly new functional programming language developed with heavy involvement of Microsoft.

My intention has been to examine, whether F# can be used for various tasks I usually perform with R (

As for now, F# looks pretty strange.

It is different in many ways from standard programming languages like C/C+. It is also different from R.

Learning it seems like solving a series of logic puzzles, at this stage.

My (very early) F# code is definitely not optimal, but it may give a hint of what may come later.

Take for example a simple function for calculating return on investment in a bond, used in my previous post.

In R, the function looks like that:

  1. # expected (discounted) return
  2. pv <- function(fa,n,cr,rf) {
  3.   -fa+sum(sapply(1:n, function(i) (fa*cr)/(1+rf)^i))+fa/(1+rf)^n
  4. }

You can see the code in context here:

Meanwhile, my F# equivalent is:

At least both functions return the same result :)

The nice thing about F# is that, although Microsoft did not include it in the free Visual Studio Express 2013, there is an online version of the F# available. You can write and test your F# code there.

OK, why F# may look strange? Just a couple of observations:
  • calculating power for floats and integers is handled differently - pown for integers and ** for floats
  • once a function is used with one type of argument - say int - you cannot use it again with any other type - say float
  • separate operations for adding a single element at the beginning of a list (::) and for joining the lists (@)
  • some symbol combinations (example: !!!), while it is possible to define the operations they perform, cannot be used between arguments, i.e. !!! 2 3 is fine, while 2 !!! 3 is not
I would like to stress again, that I am at the very beginning of my journey with F#. 

The peculiarities of F# have not discouraged me so far. I'd say, it is quite the opposite. They have increased my hunger for learning fore about this bizarre creature ;)

1 comment:

Shanejo said...

It's very useful blog post with informative and insightful content and i had good experience with this information.I have gone through CRS Info Solutions Home which really nice. Learn more details About Us of CRS info solutions. Here you can see the Courses CRS Info Solutions full list. Find Student Registration page and register now. Go through Blog post of crs info solutions. I just read these Reviews of crs really great. You can now Contact Us of crs info solutions. You enroll for Pega Training at crs info solutions.