Tutorial by Examples: e

A program unit which is not an internal subprogram may contain other program units, called internal subprograms. program prog implicit none contains function f() end function f subroutine g() end subroutine g end program Such an internal subprogram has a number of features: t...

From within a generator function, the control can be delegated to another generator function using yield*. function* g1() { yield 2; yield 3; yield 4; } function* g2() { yield 1; yield* g1(); yield 5; } var it = g2(); console.log(it.next()); // 1 console.log(it.next())...

The Observer pattern is used for event handling and delegation. A subject maintains a collection of observers. The subject then notifies these observers whenever an event occurs. If you've ever used addEventListener then you've utilized the Observer pattern. function Subject() { this.observers...

for a large number of files which may need to be operated on in a similar process and with well structured file names. firstly a vector of the file names to be accessed must be created, there are multiple options for this: Creating the vector manually with paste0() files <- paste0("f...

#include <stdio.h> #define ARRLEN (10) int main (void) { int n[ ARRLEN ]; /* n is an array of 10 integers */ size_t i, j; /* Use size_t to address memory, that is to index arrays, as its guaranteed to be wide enough to address all of the possible availab...

You should have Elm platform installed on your computer, the following tutorial is written with the assumption, that you are familiar with terminal. Initialization Create a folder and navigate to it with your terminal: $ mkdir elm-app $ cd elm-app/ Initialize Elm project and install core depe...

A distinctive syntactic peculiarity of C is that declarations mirror the use of the declared object as it would be in a normal expression. The following set of operators with identical precedence and associativity are reused in declarators, namely: the unary * "dereference" operator wh...

git diff HEAD^ HEAD This will show the changes between the previous commit and the current commit.

Freeing memory twice is undefined behavior, e.g. int * x = malloc(sizeof(int)); *x = 9; free(x); free(x); Quote from standard(7.20.3.2. The free function of C99 ): Otherwise, if the argument does not match a pointer earlier returned by the calloc, malloc, or realloc function, or if the sp...

Using an incorrect format specifier in the first argument to printf invokes undefined behavior. For example, the code below invokes undefined behavior: long z = 'B'; printf("%c\n", z); Here is another example printf("%f\n",0); Above line of code is undefined behavior. %...

These examples assume that you already know what Java 7's NIO is in general, and you are used to writing code using java.io.File. Use these examples as a means to quickly find more NIO-centric documentation for migrating. There is much more to Java 7's NIO such as memory-mapped files or opening a Z...

instance Monoid [a] where mempty = [] mappend = (++) Checking the Monoid laws for this instance: mempty `mappend` x = x <-> [] ++ xs = xs -- prepending an empty list is a no-op x `mappend` mempty = x <-> xs ++ [] = xs -- appending an empty list is a no-op x...

mconcat :: [a] -> a is another method of the Monoid typeclass: ghci> mconcat [Sum 1, Sum 2, Sum 3] Sum {getSum = 6} ghci> mconcat ["concat", "enate"] "concatenate" Its default definition is mconcat = foldr mappend mempty.

In the following examples, we'll be using the following samples: List<Product> Products = new List<Product>() { new Product() { ProductId = 1, Name = "Book nr 1", Price = 25 }, new Product() { ProductId = 2, Name = "Book nr 2&quot...

By default, user input history in IEx do not persist across different sessions. erlang-history adds history support to both the Erlang shell and IEx: git clone [email protected]:ferd/erlang-history.git cd erlang-history sudo make install You can now access your previous inputs using the up and d...

Numbers are monoidal in two ways: addition with 0 as the unit, and multiplication with 1 as the unit. Both are equally valid and useful in different circumstances. So rather than choose a preferred instance for numbers, there are two newtypes, Sum and Product to tag them for the different functional...

Wikipedia currently defines a pure function as follows: The function always evaluates the same result value given the same argument value(s). The function result value cannot depend on any hidden information or state that may change while program execution proceeds or between different executions...

Suppose we need to do the sum of each column in a dataset set.seed(20) df1 <- data.frame(ID = rep(c("A", "B", "C"), each = 3), V1 = rnorm(9), V2 = rnorm(9)) m1 <- as.matrix(df1[-1]) There are many ways to do this. Using base R, the best option would be col...

A common question is "I have a value of IO a, but I want to do something to that a value: how do I get access to it?" How can one operate on data that comes from the outside world (for example, incrementing a number typed by the user)? The point is that if you use a pure function on data ...

Suppose you have this type: data Person = Person { name :: String, age:: Int } deriving (Show, Eq) and two values: alex = Person { name = "Alex", age = 21 } jenny = Person { name = "Jenny", age = 36 } a new value of type Person can be created by copying from alex, specif...