IT Sky Consulting GmbH
We often encounter nested loops, like for (i = 0; i < n; i++) { for (j = 0; j < m; j++) { doSomething(i, j); } } This can be nested to a few more levels without too much pain, as long as we observe that the number of iterations for each level need …
„Loops with unknown nesting depth“ weiterlesen
There are many interesting languages that have their sweet spots and of course a larger set of languages than just two should be considered for new projects. But Ruby and Scala are both very interesting languages that did not just pick up and sell concepts that were already known, but brought them to a new …
„When to use Scala and Ruby“ weiterlesen
The idea is, that we have data that is obtained or calculated to give us on demand as much of it as we request. But it is not necessarily initially present. This concept is quite common in the functional world, where we in a way hide the deprecated concept of state in such structures, by …
„Lazy Collections, Strings or Numbers“ weiterlesen
It is a more and more common task that we need to have a date or maybe date with time as String. There are two reasonable ways to do this: * We may want the date formatted in the users Locale, whatever that is. * We want to use a generic date format, that is …
„How to create ISO Date String“ weiterlesen
When using integers in C, Java or Scala, we often use what is called int. It is presented to us as the default. And it is extremely fast. Ruby uses by default arbitrary length integers. But what do +, – and * mean? We can rebuild them, in Ruby, kind of artificially restrict the integers …
„What do +, – and * with Integer do?“ weiterlesen
Images are usually some obscure binary files. Their most common formats, PNG, SVG, JPEG and GIF are well documented and supported by many software tools. Libraries and APIs exist for accessing these formats, but also a phantastic free interactive software like Gimp. The compression rate that can reasonably be achieved when using these format is …
„Conversion of ASCII-graphics to PNG or JPG“ weiterlesen
In Facebook, Xing, Google+, Vk.com, Linkedin and other of these social media networks we are often encountered with a trivial question like this: 1->2 2->8 3->18 4->32 5->50 6->72 7->? There are some easy patterns. Either it is some polynomial formula or some trick with the digits. But the point is, that any such sequence …
„Find the next entry in a sequence“ weiterlesen
It is very important to write good unit tests for software that is non-trivial and that is relied on by other pieces of software. Often the logic of the software can easily be covered by the native testing facilities of the programming language, like JUnit for Java or, much less well known but available, CUnit …
„Testing Java- and C-programs with Ruby and Perl“ weiterlesen
Some years ago Ruby in conjunction with rails was an absolute hype. In the Rails User Group in Zürich we had meetups with 30 people every two weeks. The meetings every two weeks have been retained, but often we are just five to ten people now. Is the great time of Ruby over or is …
„Why I still like Ruby“ weiterlesen
Monads? Easy! A Monad over X simply is a Monoid in the Category of Endofunctors of X. Monads? Really! Monads are a concept in mathematics Algebra is an area of mathematics Category theory is an abstraction of algebra. Monads are defined in category theory Remember: in category theory we talk about infinity beyond cardinality of …