What exactly is a Monad?

Posted by WeNeedAnswers on Stack Overflow See other posts from Stack Overflow or by WeNeedAnswers
Published on 2010-03-23T15:38:56Z Indexed on 2010/03/23 15:43 UTC
Read the original article Hit count: 284

Filed under:

haskell

|

python

|

monads

Can someone please explain to me what a Monad is. I think I grasp Monoids and I grasp that they basically control the input of state into a system.

I just look at the text in Haskell and glaze over. A simple example in python would be great.

My current understanding is that a Monoid is a procedural piece of code that needs to be read from top to bottom in sequence with the output being the input for the function.

I think that I may even got that wrong, but hey I am here to learn.

© Stack Overflow or respective owner

Related posts about haskell

Learning Haskell: How to remove an item from a List in Haskell

as seen on Stack Overflow - Search for 'Stack Overflow'
Trying to learn Haskell. I am trying to write a simple function to remove a number from a list without using built-in function (delete...I think). For the sake of simplicity, let's assume that the input parameter is an Integer and the list is an Integer list. Here is the code I have, Please tell me… >>> More
Using Data.Heap in Haskell, or reading Haskell docs for a beginner

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to use Haskells Data.Heap module, but I'm incapable of even using it with integers. The only heap I've been capable of using is "empty", which does not take any arguments. Later on I'll figure out how to instance for my needs, but for now I'd be glad if I was even able to test it with… >>> More
What kind of things are easy in Haskell and hard in Scala, and vice versa?

as seen on Programmers - Search for 'Programmers'
There has been some intermingling of Scala and Haskell communities, and I have noticed now and then people commenting on stuff that's supposed to be easy in Haskell and hard and Scala. Less often (maybe because I read Scala questions, not Haskell ones), I see someone mentioning that something in Scala… >>> More
Haskell's cabal dependency problem with happy

as seen on Programmers - Search for 'Programmers'
I have problems installing ghc-mod on my linux machine. cabal worries about "happy" not being available in versione = 1.17: $ cabal install ghc-mod Resolving dependencies... [1 of 1] Compiling Main ( /tmp/haskell-src-exts-1.14.0-1357/haskell-src-exts-1.14.0/Setup.hs, /tmp/haskell-src-exts-1… >>> More
Understanding Haskell's fibonacci

as seen on Stack Overflow - Search for 'Stack Overflow'
fibs :: [Int] fibs = 0 : 1 : [ a + b | (a, b) <- zip fibs (tail fibs)] This generates the Fibonacci sequence. I understand the behaviour of the guards, of :, zip and tail, but I don't understand <-. What is it doing here? >>> More

Related posts about python

unmet dependencies in Ubuntu 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried today to install a dvb-card on my Ubuntu 12.04 (Linux blauhai-linux 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux ). The installation failed with an error. After that, i tried to install python (it was already installed but i got this error): linux:~$… >>> More
How can I get sikuli-ide to work?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I installed sikuli-ide with sudo apt-get install sikuli-ide Everything was fine until I tried to start it from the terminal. I typed sikuli-ide But the only response I got was [info] locale: en_US The application was not started, furthermore there is no desktop file and sikuli-ide does not… >>> More
Getting PATH right for python after MacPorts install

as seen on Super User - Search for 'Super User'
I can't import some python libraries (PIL, psycopg2) that I just installed with MacPorts. I looked through these forums, and tried to adjust my PATH variable in $HOME/.bash_profile in order to fix this but it did not work. I added the location of PIL and psycopg2 to PATH. I know that Terminal is… >>> More
call python with system() in R to run a python script emulating the python console

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to pass a chunk of Python code to Python in R with something like system('python ...'), and I'm wondering if there is an easy way to emulate the python console in this case. For example, suppose the code is "print 'hello world'", how can I get the output like this in R? >>> print… >>> More
Python - Calling a non python program from python?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am currently struggling to call a non python program from a python script. I have a ~1000 files that when passed through this C++ program will generate ~1000 outputs. Each output file must have a distinct name. The command I wish to run is of the form: program_name -input -output -o1 -o2… >>> More