Tutorial by Examples: num

You can enumerate through a Dictionary in one of 3 ways: Using KeyValue pairs Dictionary<int, string> dict = new Dictionary<int, string>(); foreach(KeyValuePair<int, string> kvp in dict) { Console.WriteLine("Key : " + kvp.Key.ToString() + ", Value : " +...

The enum keyword tells the compiler that this class inherits from the abstract class Enum, without the programmer having to explicitly inherit it. Enum is a descendant of ValueType, which is intended for use with distinct set of named constants. public enum DaysOfWeek { Monday, Tuesday, ...

An enum is a special type of class. The enum keyword tells the compiler that this class inherits from the abstract System.Enum class. Enums are used for distinct lists of items. public enum MyEnum { Monday = 1, Tuesday, Wednesday, //... } You can think of an enum as a conve...

NumberFormatInfo can be used for formatting both integer and float numbers. // invariantResult is "1,234,567.89" var invarianResult = string.Format(CultureInfo.InvariantCulture, "{0:#,###,##}", 1234567.89); // NumberFormatInfo is one of classes that implement IFormatProvider...

In the ActionListener attached to a javax.swing.Timer, you can keep track of the number of times the Timer executed the ActionListener. Once the required number of times is reached, you can use the Timer#stop() method to stop the Timer. Timer timer = new Timer( delay, new ActionListener() { priv...

OptionalDouble, OptionalInt and OptionalLong work like Optional, but are specifically designed to wrap primitive types: OptionalInt presentInt = OptionalInt.of(value); OptionalInt absentInt = OptionalInt.empty(); Because numeric types do have a value, there is no special handling for null. Empt...

Enum can be considered to be syntax sugar for a sealed class that is instantiated only a number of times known at compile-time to define a set of constants. A simple enum to list the different seasons would be declared as follows: public enum Season { WINTER, SPRING, SUMMER, FA...

An enum cannot have a public constructor; however, private constructors are acceptable (constructors for enums are package-private by default): public enum Coin { PENNY(1), NICKEL(5), DIME(10), QUARTER(25); // usual names for US coins // note that the above parentheses and the constructor...

An enum provides a set of related values: enum Direction { case up case down case left case right } enum Direction { case up, down, left, right } Enum values can be used by their fully-qualified name, but you can omit the type name when it can be inferred: let dir = Dire...

Enum cases can contain one or more payloads (associated values): enum Action { case jump case kick case move(distance: Float) // The "move" case has an associated distance } The payload must be provided when instantiating the enum value: performAction(.jump) performA...

Setting a specific Seed will create a fixed random-number series: random.seed(5) # Create a fixed state print(random.randrange(0, 10)) # Get a random integer between 0 and 9 # Out: 9 print(random.randrange(0, 10)) # Out: 4 Resetting the seed will create the same &qu...

Arbitrary number of positional arguments: Defining a function capable of taking an arbitrary number of arguments can be done by prefixing one of the arguments with a * def func(*args): # args will be a tuple containing all values that are passed in for i in args: print(i) fun...

def input_number(msg, err_msg=None): while True: try: return float(raw_input(msg)) except ValueError: if err_msg is not None: print(err_msg) def input_number(msg, err_msg=None): while True: try: return ...

A practical use case of a generator is to iterate through values of an infinite series. Here's an example of finding the first ten terms of the Fibonacci Sequence. def fib(a=0, b=1): """Generator that yields Fibonacci numbers. `a` and `b` are the seed values""" ...

One method is available for counting the number of occurrences of a sub-string in another string, str.count. str.count(sub[, start[, end]]) str.count returns an int indicating the number of non-overlapping occurrences of the sub-string sub in another string. The optional arguments start and end ...

The type of the literal Prelude> :t 1 1 :: Num a => a choosing a concrete type with annotations You can specify the type as long as the target type is Num with an annotation: Prelude> 1 :: Int 1 it :: Int Prelude> 1 :: Double 1.0 it :: Double Prelude> 1 :: Word 1 it :: ...

The type of the literal Prelude> :t 1.0 1.0 :: Fractional a => a Choosing a concrete type with annotations You can specify the type with a type annotation. The only requirement is that the type must have a Fractional instance. Prelude> 1.0 :: Double 1.0 it :: Double Prelude> 1....

The function rand() can be used to generate a pseudo-random integer value between 0 and RAND_MAX (0 and RAND_MAX included). srand(int) is used to seed the pseudo-random number generator. Each time rand() is seeded wih the same seed, it must produce the same sequence of values. It should only be see...

#! /bin/bash for i in {1..10}; do # {1..10} expands to "1 2 3 4 5 6 7 8 9 10" echo $i done This outputs the following: 1 2 3 4 5 6 7 8 8 10

Use the --number flag to print line numbers before each line. Alternatively, -n does the same thing. $ cat --number file 1 line 1 2 line 2 3 4 line 4 5 line 5 To skip empty lines when counting lines, use the --number-nonblank, or simply -b. $ cat -b file 1 line 1 2 line ...