To understand recursion you must first understand recursion.
I thought I understood recursion
11–20 of 124 posts
Re: I thought I understood recursion
#12Ooh, what's the time and space complexity of `primes`?
Primes is in p
Re: I thought I understood recursion
#13I do not get what this publication is trying to say. Is Haskell better than C#? are Haskell programs shorter than C#? is recursion difficult? is recursion difficult in C#? I don't get it.
Re: I thought I understood recursion
#14> My background is in OO programming, mostly using C#. C# being the versatile language it is, I have had the perception that whatever you do in other programming languages, you can with a little more code and hassle achieve in C# as well. If need be, I can program C# using a functional paradigm. And, of course I use recursion all the time. I know all there is to know about recursion. IME there are two kinds of progra…
So if you consider some stack to be inferior (maybe because its highly inconsistent in its design or it only runs on closed and locked down platforms or whatever) you still should just dismiss it as 'oh its just a tool' instead of accepting that it's shitty and makes you miserable when working with it? Why wouldn't I want to work with best thing ever if it helps me keep my sanity every day? Do you want to use somethi…
The argument is to use the right tool for the right job and not just the hammer that you’ve become an expert in.
If you know of a tool that is the wrong tool for every job, then yes, it’s still just a tool. Just use something else.
Re: I thought I understood recursion
#15> My background is in OO programming, mostly using C#. C# being the versatile language it is, I have had the perception that whatever you do in other programming languages, you can with a little more code and hassle achieve in C# as well. If need be, I can program C# using a functional paradigm. And, of course I use recursion all the time. I know all there is to know about recursion. IME there are two kinds of progra…
So if you consider some stack to be inferior (maybe because its highly inconsistent in its design or it only runs on closed and locked down platforms or whatever) you still should just dismiss it as 'oh its just a tool' instead of accepting that it's shitty and makes you miserable when working with it? Why wouldn't I want to work with best thing ever if it helps me keep my sanity every day? Do you want to use somethi…
Maybe you should look within yourself and fix up whatever part of your personality is making you miserable? I'm not being flippant. Programming languages don't make people miserable.
There isn't really an argument, just an observation that the most efficient way of thinking about programming is in data structures and algorithms which are mostly language independent. Nobody should be spending most of their time leveraging language features, so it isn't critical to use any particular language.
I have a large range of pens of different quality. I have a favourite pen. But I'm willing to use any pen if I need to write something down. My focus is on composing a message, not on worrying about the quality of my calligraphy or the occasional scratchy mark. If 'm going to be writing all day I'd rather have my favourite pen but any one will do.
Re: I thought I understood recursion
#16> My background is in OO programming, mostly using C#. C# being the versatile language it is, I have had the perception that whatever you do in other programming languages, you can with a little more code and hassle achieve in C# as well. If need be, I can program C# using a functional paradigm. And, of course I use recursion all the time. I know all there is to know about recursion. IME there are two kinds of progra…
So if you consider some stack to be inferior (maybe because its highly inconsistent in its design or it only runs on closed and locked down platforms or whatever) you still should just dismiss it as 'oh its just a tool' instead of accepting that it's shitty and makes you miserable when working with it? Why wouldn't I want to work with best thing ever if it helps me keep my sanity every day? Do you want to use somethi…
Vast majority of the time, I pick up a project half-way with an existing codebase rather than start from scratch, and it's natural to just keep using what's there unless there's a showstopper, in which case I make the bare minimum addition so I could keep going.
So yeah, just a tool.
Re: I thought I understood recursion
#17> My background is in OO programming, mostly using C#. C# being the versatile language it is, I have had the perception that whatever you do in other programming languages, you can with a little more code and hassle achieve in C# as well. If need be, I can program C# using a functional paradigm. And, of course I use recursion all the time. I know all there is to know about recursion. IME there are two kinds of progra…
So if you consider some stack to be inferior (maybe because its highly inconsistent in its design or it only runs on closed and locked down platforms or whatever) you still should just dismiss it as 'oh its just a tool' instead of accepting that it's shitty and makes you miserable when working with it? Why wouldn't I want to work with best thing ever if it helps me keep my sanity every day? Do you want to use somethi…
I think an analogy would be the following:
You need to hammer a nail in a piece of wood. You could do this with a screwdriver but hammer is better suited for the job. However, a hammer made out of glass is less useful than the screwdriver.
In other words, some kinds of tools are better suited for a problem than others, but there exist tools that inferior even though they were designed to solve your original problem.
You should pick the best tool for the job. It might be unclear what that tool is and some tools are better than others at solving the same problem, even if they are designed to solve the same problem.
Re: I thought I understood recursion
#18Ooh, what's the time and space complexity of `primes`?
Clearly much worse than the original solution. Basically, a nested sequence of filters is built, one to filter out multiples of each prime number. One way in which the complexity of this is bad is that if you want prime numbers These kind of functional solutions are very cute mathematically, but...
I once wrote this way of generating an infinite list of primes in unlambda. That was kind of interesting to do.
Re: I thought I understood recursion
#19Ooh, what's the time and space complexity of `primes`?
I'd say O(n) for both. The generated list only contains primes, so that's straightforward linear. Then there is the recursive sieving, which adds an additional pass over the sieve list for every prime we've found so far, we need keep the computation of each pass in memory, so that's some additional memory that's also linear.
The time complexity is less obvious, each prime adds an additional pass to evaluate, so that seems linear, but each new pass only applies to a list that already had all the previous passes filtered out, so that's not technically linear, but I find it hard to determine how much it actually is.
Re: I thought I understood recursion
#20The Haskell code can be slightly simplified to
nth :: Integral a => Int -> Maybe a
nth n | n [a]
primes = sieve [2..]
where sieve (p:xs) = p : sieve [x | x