diff --git a/java.html.markdown b/java.html.markdown index e14f356d..f6890d9b 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -15,173 +15,173 @@ Read more here: https://en.wikipedia.org/wiki/Java_(programming_language) /////////////////////////////////////// // General /////////////////////////////////////// - // Single-line comments start with // - /* - Multi-line comments look like this. - */ - - // Import Packages - import java.util.ArrayList; - import package.path.here; - // Import all "sub-packages" - import java.lang.Math.*; - - // Your program's entry point is a function called main - public class Main - { - public static void main (String[] args) throws java.lang.Exception - { - //stuff here - } - } - - // Printing, and forcing a new line on next print = println() - System.out.println("Hello World"); - System.out.println("Integer: "+10+"Double: "+3.14+ "Boolean: "+true); - // Printing, without forcing a new line on next print = print() - System.out.print("Hello World"); - System.out.print("Integer: "+10+"Double: "+3.14+ "Boolean: "+true); +// Single-line comments start with // +/* +Multi-line comments look like this. +*/ + +// Import Packages +import java.util.ArrayList; +import package.path.here; +// Import all "sub-packages" +import java.lang.Math.*; + +// Your program's entry point is a function called main +public class Main +{ + public static void main (String[] args) throws java.lang.Exception + { + //stuff here + } +} + +// Printing, and forcing a new line on next print = println() +System.out.println("Hello World"); +System.out.println("Integer: "+10+"Double: "+3.14+ "Boolean: "+true); +// Printing, without forcing a new line on next print = print() +System.out.print("Hello World"); +System.out.print("Integer: "+10+"Double: "+3.14+ "Boolean: "+true); /////////////////////////////////////// // Types /////////////////////////////////////// - // Byte - 8-bit signed two's complement integer (-128 <= byte <= 127) - byte foo = 100; - - // Short - 16-bit signed two's complement integer (-32,768 <= short <= 32,767) - short bar = 10000; - - //Integer - 32-bit signed two's complement integer (-2,147,483,648 <= int <= 2,147,483,647) - int foo = 1; - - //Long - 64-bit signed two's complement integer (-9,223,372,036,854,775,808 <= long <= 9,223,372,036,854,775,807) - long bar = 100000L; - - //Float - Single-precision 32-bit IEEE 754 Floating Point - float foo = 234.5f; - - //Double - Double-precision 64-bit IEEE 754 Floating Point - double bar = 123.4; - - //Boolean - True & False - boolean foo = true; - boolean bar = false; - - //Char - A single 16-bit Unicode character - char foo = 'A'; - - //Make a variable a constant - final int HOURS_I_WORK_PER_WEEK = 9001; - - //Strings - String foo = "Hello World!"; - // \n is an escaped character that starts a new line - String foo = "Hello World!\nLine2!"; - System.out.println(foo); - //Hello World! - //Line2! - - //Arrays - //The array size must be decided upon declaration - //The format for declaring an array is follows: - // [] = new []; - int [] array = new int[10]; - String [] array = new String[1]; - boolean [] array = new boolean[100]; - - // Indexing an array - Accessing an element - array[0]; - - // Arrays are mutable; it's just memory! - array[1] = 1; - System.out.println(array[1]); // => 1 - array[1] = 2; - System.out.println(array[1]); // => 2 - - //Others to check out - //ArrayLists - Like arrays except more functionality is offered, and the size is mutable - //LinkedLists - //Maps - //HashMaps +// Byte - 8-bit signed two's complement integer (-128 <= byte <= 127) +byte foo = 100; + +// Short - 16-bit signed two's complement integer (-32,768 <= short <= 32,767) +short bar = 10000; + +//Integer - 32-bit signed two's complement integer (-2,147,483,648 <= int <= 2,147,483,647) +int foo = 1; + +//Long - 64-bit signed two's complement integer (-9,223,372,036,854,775,808 <= long <= 9,223,372,036,854,775,807) +long bar = 100000L; + +//Float - Single-precision 32-bit IEEE 754 Floating Point +float foo = 234.5f; + +//Double - Double-precision 64-bit IEEE 754 Floating Point +double bar = 123.4; + +//Boolean - True & False +boolean foo = true; +boolean bar = false; + +//Char - A single 16-bit Unicode character +char foo = 'A'; + +//Make a variable a constant +final int HOURS_I_WORK_PER_WEEK = 9001; + +//Strings +String foo = "Hello World!"; +// \n is an escaped character that starts a new line +String foo = "Hello World!\nLine2!"; +System.out.println(foo); +//Hello World! +//Line2! + +//Arrays +//The array size must be decided upon declaration +//The format for declaring an array is follows: +// [] = new []; +int [] array = new int[10]; +String [] array = new String[1]; +boolean [] array = new boolean[100]; + +// Indexing an array - Accessing an element +array[0]; + +// Arrays are mutable; it's just memory! +array[1] = 1; +System.out.println(array[1]); // => 1 +array[1] = 2; +System.out.println(array[1]); // => 2 + +//Others to check out +//ArrayLists - Like arrays except more functionality is offered, and the size is mutable +//LinkedLists +//Maps +//HashMaps /////////////////////////////////////// // Operators /////////////////////////////////////// - int i1 = 1, i2 = 2; // Shorthand for multiple declarations - - // Arithmetic is straightforward - i1 + i2; // => 3 - i2 - i1; // => 1 - i2 * i1; // => 2 - i1 / i2; // => 0 (0.5, but truncated towards 0) - - // Modulo - 11 % 3; // => 2 - - // Comparison operators - 3 == 2; // => 0 (false) - 3 != 2; // => 1 (true) - 3 > 2; // => 1 - 3 < 2; // => 0 - 2 <= 2; // => 1 - 2 >= 2; // => 1 - - // Bitwise operators! - ~ Unary bitwise complement - << Signed left shift - >> Signed right shift - >>> Unsigned right shift - & Bitwise AND - ^ Bitwise exclusive OR - | Bitwise inclusive OR - - // Incrementations - int i=0; - i++; //i = 1. Post-Incrementation - ++i; //i = 2. Pre-Incrementation - i--; //i = 1. Post-Decrementation - --i; //i = 0. Pre-Decrementation +int i1 = 1, i2 = 2; // Shorthand for multiple declarations + +// Arithmetic is straightforward +i1 + i2; // => 3 +i2 - i1; // => 1 +i2 * i1; // => 2 +i1 / i2; // => 0 (0.5, but truncated towards 0) + +// Modulo +11 % 3; // => 2 + +// Comparison operators +3 == 2; // => 0 (false) +3 != 2; // => 1 (true) +3 > 2; // => 1 +3 < 2; // => 0 +2 <= 2; // => 1 +2 >= 2; // => 1 + +// Bitwise operators! +~ Unary bitwise complement +<< Signed left shift +>> Signed right shift +>>> Unsigned right shift +& Bitwise AND +^ Bitwise exclusive OR +| Bitwise inclusive OR + +// Incrementations +int i=0; +i++; //i = 1. Post-Incrementation +++i; //i = 2. Pre-Incrementation +i--; //i = 1. Post-Decrementation +--i; //i = 0. Pre-Decrementation /////////////////////////////////////// // Control Structures /////////////////////////////////////// - if (false) { - System.out.println("I never run"); - } else if (false) { - System.out.println("I am also never run"); - } else { - System.out.println("I print"); - } - } +if (false) { + System.out.println("I never run"); + } else if (false) { + System.out.println("I am also never run"); + } else { + System.out.println("I print"); + } +} - // While loop - int i = 0; - while(i < 100){ - System.out.println(i); - //Increment the counter - i++; - } - - // Do While Loop - int i = 0; - do{ - System.out.println(i); - //Increment the counter - i++; - }while(i < 100); - - // For Loop - int i; - //for loop structure => for(;;) - for(i=0;i<100;i++){ - System.out.println(i); - } - - // Switch Case - int month = 8; +// While loop +int i = 0; +while(i < 100){ + System.out.println(i); + //Increment the counter + i++; +} + +// Do While Loop +int i = 0; +do{ + System.out.println(i); + //Increment the counter + i++; +}while(i < 100); + +// For Loop +int i; +//for loop structure => for(;;) +for(i=0;i<100;i++){ + System.out.println(i); +} + +// Switch Case +int month = 8; String monthString; switch (month) { case 1: monthString = "January"; @@ -217,88 +217,88 @@ Read more here: https://en.wikipedia.org/wiki/Java_(programming_language) // Typecasting /////////////////////////////////////// - // Converting data - - //Convert String To Integer - Integer.parseInt("123");//returns an integer version of "123" - - //Convert Integer To String - Integer.toString(123);//returns a string version of 123 - - //For other conversions check out the following classes: - //Double - //Long - //String - - // You can also cast java objects, there's a lot of details and - // deals with some more intermediate concepts. - // Feel free to check it out here: http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html - +// Converting data + +//Convert String To Integer +Integer.parseInt("123");//returns an integer version of "123" + +//Convert Integer To String +Integer.toString(123);//returns a string version of 123 + +//For other conversions check out the following classes: +//Double +//Long +//String + +// You can also cast java objects, there's a lot of details and +// deals with some more intermediate concepts. +// Feel free to check it out here: http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html + /////////////////////////////////////// // Classes And Functions /////////////////////////////////////// - // Classes Syntax shown below. - // Function declaration syntax: - // () - // Here is a quick rundown on access level modifiers (public, private, etcetc) http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html +// Classes Syntax shown below. +// Function declaration syntax: +// () +// Here is a quick rundown on access level modifiers (public, private, etcetc) http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html - - public class Bicycle { - - // Bicycle's Fields/Variables - public int cadence; - public int gear; - public int speed; - - // Constructors are a way of creating classes - // This is a default constructor - public Bicycle(){ - gear = 1; - cadence = 50; - startGear = 1; - } - // This is a specified constructor (it contains arguments) - public Bicycle(int startCadence, int startSpeed, int startGear) { - gear = startGear; - cadence = startCadence; - speed = startSpeed; - } - - // the Bicycle class has - // four methods - public void setCadence(int newValue) { - cadence = newValue; - } - - public void setGear(int newValue) { - gear = newValue; - } - - public void applyBrake(int decrement) { - speed -= decrement; - } - - public void speedUp(int increment) { - speed += increment; - } - - } - - //Now..Later in the main / driver of your java program - public class Main - { - public static void main (String[] args) throws java.lang.Exception - { - //Call bicycle's constructor - Bicycle trek = new Bicycle(); - //Manipulate your object - trek.speedUp(3); - trek.setCadence(100); - } - } +public class Bicycle { + + // Bicycle's Fields/Variables + public int cadence; + public int gear; + public int speed; + + // Constructors are a way of creating classes + // This is a default constructor + public Bicycle(){ + gear = 1; + cadence = 50; + startGear = 1; + } + + // This is a specified constructor (it contains arguments) + public Bicycle(int startCadence, int startSpeed, int startGear) { + gear = startGear; + cadence = startCadence; + speed = startSpeed; + } + + // the Bicycle class has + // four methods + public void setCadence(int newValue) { + cadence = newValue; + } + + public void setGear(int newValue) { + gear = newValue; + } + + public void applyBrake(int decrement) { + speed -= decrement; + } + + public void speedUp(int increment) { + speed += increment; + } + +} + +//Now..Later in the main / driver of your java program +public class Main +{ + public static void main (String[] args) throws java.lang.Exception + { + //Call bicycle's constructor + Bicycle trek = new Bicycle(); + //Manipulate your object + trek.speedUp(3); + trek.setCadence(100); + } +} ``` @@ -306,14 +306,14 @@ Read more here: https://en.wikipedia.org/wiki/Java_(programming_language) Other Topics To Research: - * Inheritance (http://en.wikipedia.org/wiki/Inheritance_(object-oriented_programming)) - - * Abstraction (http://en.wikipedia.org/wiki/Abstraction_(computer_science)) - - * Exceptions (http://en.wikipedia.org/wiki/Exception_handling) - - * Interfaces (http://en.wikipedia.org/wiki/Interfaces_(computer_science)) - - * Generics (http://en.wikipedia.org/wiki/Generics_in_Java) - - * The links provided are just to get an understanding of the topic, feel free to google and find specific examples +* Inheritance (http://en.wikipedia.org/wiki/Inheritance_(object-oriented_programming)) + +* Abstraction (http://en.wikipedia.org/wiki/Abstraction_(computer_science)) + +* Exceptions (http://en.wikipedia.org/wiki/Exception_handling) + +* Interfaces (http://en.wikipedia.org/wiki/Interfaces_(computer_science)) + +* Generics (http://en.wikipedia.org/wiki/Generics_in_Java) + +* The links provided are just to get an understanding of the topic, feel free to google and find specific examples diff --git a/python.html.markdown b/python.html.markdown index d1152b82..467a179e 100644 --- a/python.html.markdown +++ b/python.html.markdown @@ -111,7 +111,7 @@ except NameError: print "Raises a name error" # if can be used as an expression -some_var = a if a > b else b +some_var = 1 if 1 > 2 else 2 # => 2 # If a is greater than b, then a is assigned to some_var. # Otherwise b is assigned to some_var. @@ -207,8 +207,11 @@ filled_dict.values() #=> [3, 2, 1] "one" in filled_dict #=> True 1 in filled_dict #=> False -# Trying to look up a non-existing key will raise a KeyError -filled_dict["four"] #=> KeyError +try: + # Trying to look up a non-existing key will raise a KeyError + filled_dict["four"] #=> KeyError +except KeyError: + pass # Use get method to avoid the KeyError filled_dict.get("one") #=> 1 @@ -235,7 +238,7 @@ filled_set = {1, 2, 2, 3, 4} # => {1 2 3 4} filled_set.add(5) # filled_set is now {1, 2, 3, 4, 5} # Do set intersection with & -other_set = set{3, 4, 5, 6} +other_set = {3, 4, 5, 6} filled_set & other_set #=> {3, 4, 5} # Do set union with | @@ -337,7 +340,7 @@ def keyword_args(**kwargs): keyword_args(big="foot", loch="ness") #=> {"big": "foot", "loch": "ness"} # You can do both at once, if you like -def all_the_args(*args, **kwargs): +def foo(*args, **kwargs): print args print kwargs """