![]() ![]() Irb > my_own_block ( p 5 ) 5 Traceback ( most recent call last ): 6 : from /home/ agnieszka /. A common block in Ruby is for example each: In Ruby blocks are higher-order functions. There can be only one block put as an argument in Ruby method. ![]() We can put it as last argument into function. Blocks in Rubyīlock it is nameless function in Ruby. We can start going into Ruby functional programming. Now we know a little bit about functional programming concepts. Lazy evaluation (non-strict evaluation) - It does not evaluate function arguments unless their values are needed for evaluation of the function itself.Recursion - It is invoking the function by themselves and letting an operation be repeated until it reaches the stop condition or base case.We can say that this is a function generator in some sense. Currying - Transforming a function that takes multiple arguments into a function that takes one argument and return function.Higher-order functions - Functions which can get function as argument or return function as a result.This is also a side effect of referential transparency. Idempotence - You will get the same results no matter how many times you will call a function.It can seed up computations by saving the results of previous calls. Memoization - It is a side effect of referential transparency.Referential transparency - this is combining pure function and immutability.Instead of changing state or value, you create a new one. Immutability - After the state/value is created, you cannot change it.This is how the function works in the mathematical world. Pure functions (no side-effects) - Function always returns the same result for the same arguments and function can never cause any observable side effects.OK, so what are the features of functional programming language? That means it is a way to classify programming languages based on their features. What is functional programming? You can find out, that functional programming is a programming paradigm. Let’s focus on functional programming its self. Because of this different inspirations we can find in Ruby not only object oriented concepts, but also a little bit of functional programming.īefore we start going deep in functional programming in Ruby. When you take a look closer to the history of the Ruby language, you can find out, that Ruby was influenced by other languages like Perl, Smalltalk, Eiffel, Ada, Basic or Lisp. That doesn’t mean we cannot do some functional programming in Ruby. If you have any questions, I’d be glad to hear them in the comments.Ruby is an object oriented language. Fixing invalid UTF-8 in Ruby, revisited.Ruby 1.9: invalid byte sequence in UTF-8.Otherwise if the source string is already encoded in UTF-8, then just calling encode('UTF-8') is a no-op, and no checks are run. In this case, force_encoding forces an encoding conversion (and with it the check for invalid characters). The double encoding trick is necessary, as I was reading ISO 8859-1 encoded files as UTF-8. directory? ( path ) ? build_tree ( path ) : change_text_file ( path ) end end build_tree ( start_path ) join ( start_path, file_name ) next if /^\./ =~ file_name next if not /.htm/. print inhalt end end def build_tree ( start_path ) Dir. sub ( "whatever", "new whatever" ) end file_contents += line end end File. open ( path, 'r' ) do | file | while line = file. #encoding: UTF-8 start_path = "/path/to/parent/directory/" def change_text_file ( path ) file_contents = "" File. ![]()
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