From eef092a02aa6518bb222ce022f9d9ed3d5c0fc61 Mon Sep 17 00:00:00 2001 From: talhafarooq68 Date: Mon, 10 Aug 2020 20:29:51 +0500 Subject: [PATCH] Update python.py --- Languages/python.py | 428 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 426 insertions(+), 2 deletions(-) diff --git a/Languages/python.py b/Languages/python.py index 43cbff9..1154b87 100644 --- a/Languages/python.py +++ b/Languages/python.py @@ -17,7 +17,431 @@ #************************************** -# Basic Commands +# Basic Commands & Examples #************************************** -Print("Hello World") \ No newline at end of file +#************************************** +# Python Variables +#************************************** + +# ->Creating Variable +# Variables are containers for storing data values. +# Unlike other programming languages, Python has no +# command for declaring a variable. +# A variable is created the moment you first assign +# a value to it. + + # ->Example + +x = 5 #x is of int +y = "John" #y is string +print(x) +print(y) + + # ->Output + # 5 + # John + +# Variables do not need to be declared with any particular +# type and can even change type after they have been set. + + # ->Example + +x = 4 # x is of type int +x = "Sally" # x is now of type str +print(x) + + # ->Output + # sally + +# String variables can be declared either by using single +# or double quotes: + + # ->Example +x = "John" +# is the same as +x = 'John' + + # ->Output + # John + + # Variable Names + # -> A variable can have a short name (like x and y) or a more + # descriptive name (age, carname, total_volume). Rules for Python variables: + # -> A variable name must start with a letter or the underscore character + # -> A variable name cannot start with a number + # -> A variable name can only contain alpha-numeric characters + # and underscores (A-z, 0-9, and _ ) + # -> Variable names are case-sensitive (age, Age and AGE are + # three different variables) + + # ->Example + #Legal variable names: + # myvar = "John" + # my_var = "John" + # _my_var = "John" + # myVar = "John" + # MYVAR = "John" + # myvar2 = "John" + + #Illegal variable names: + # 2myvar = "John" + # my-var = "John" + # my var = "John" + +# Assign Value to Multiple Variables +# Python allows you to assign values to multiple variables in one line: + + # ->Example + +x, y, z = "Orange", "Banana", "Cherry" +print(x) +print(y) +print(z) + + # ->Output + # Orange + # Banana + # Cherry + + # And you can assign the same value to multiple variables in one line: + + # ->Example +x = y = z = "Orange" +print(x) +print(y) +print(z) + + # ->Output + # Orange + + # You can also use the + character to add a variable to another variable: + + # ->Example + +x = "Python is " +y = "awesome" +z = x + y +print(z) + + # ->Output + # Python is awesome + + # If you try to combine a string and a number, Python will give you an error: + + # ->Example +x = 5 +y = "John" +print(x + y) + + # ->Output + # error + + # Global Variables + + # Variables that are created outside of a function are known as global variables. + # Global variables can be used by everyone, both inside of functions and outside. + + # Create a variable outside of a function, and use it inside the function + +x = "awesome" + +def myfunc(): + print("Python is " + x) + +myfunc() + + # ->Output + # Python is awesome + + # If you create a variable with the same name inside a function, this variable will + # be local, and can only be used inside the function. The global variable with the + # same name will remain as it was, global and with the original value. + + # ->Example + # Create a variable inside a function, with the same name as the global variable + +x = "awesome" + +def myfunc(): + x = "fantastic" +print("Python is " + x) + +myfunc() + +print("Python is " + x) + + # ->Output + # Python is fantastic + # Python is awesome + + # The global Keyword + + # Normally, when you create a variable inside a function, that variable is local, + # and can only be used inside that function. + # To create a global variable inside a function, you can use the global keyword. + + # ->Example + # If you use the global keyword, the variable belongs to the global scope: + +def myfunc(): + global x +x = "fantastic" + +myfunc() + +print("Python is " + x) + + # ->Output + # Python is fantastic + + # Also, use the global keyword if you want to change a global variable inside a + # function. + + # ->Example + # To change the value of a global variable inside a function, refer to the variable by using the global keyword: + +x = "awesome" + +def myfunc(): + global x +x = "fantastic" + +myfunc() + +print("Python is " + x) + + # ->Output + # Python is fantastic + + +#************************************** +# Python Data Types +#************************************** + +# Built-in Data Types + + # In programming, data type is an important concept. + # Variables can store data of different types, and different types can do different things. + # Python has the following data types built-in by default, in these + # categories: + + # -> Text Type: str + # -> Numeric Types: int, float, complex + # -> Sequence Types: list, tuple, range + # -> Mapping Type: dict + # -> Set Types: set, frozenset + # -> Boolean Type: bool + # -> Binary Types: bytes, bytearray, memoryview + + + # Getting the Data Type + + # You can get the data type of any object by using the type() function: + + # ->Example + # Print the data type of the variable x: + +x = 5 +print(type(x)) + + # # ->Output + # # + + + # Setting the Data Type + + # In Python, the data type is set when you assign a value to a variable: + + # ->Example Data Type + + +x = "Hello World" #str +x = 20 #int +x = 20.5 #float +x = 1j #complex +x = ["apple", "banana", "cherry"] #list +x = ("apple", "banana", "cherry") #tuple +x = range(6) #range +x = {"name" : "John", "age" : 36} #dict +x = {"apple", "banana", "cherry"} #set +x = frozenset({"apple", "banana", "cherry"}) #frozenset +x = True #bool +x = b"Hello" #bytes +x = bytearray(5) #bytearray +x = memoryview(bytes(5)) #memoryview + + # Setting the Specific Data Type + + # If you want to specify the data type, you can use the following constructor functions: + + # ->Example Data Type + + +x = str("Hello World") #str +x = int(20) #int +x = float(20.5) #float +x = complex(1j) #complex +x = list(("apple", "banana", "cherry")) #list +x = tuple(("apple", "banana", "cherry")) #tuple +x = range(6) #range +x = dict(name="John", age=36) #dict +x = set("apple", "banana", "cherry") #set +x = frozenset(("apple", "banana", "cherry")) #frozenset +x = bool(5) #bool +x = bytes(5) #bytes +x = bytearray(5) #bytearray +x = memoryview(bytes(5)) #memoryview + + +#************************************** +# Python Numbers: +#************************************** + +# There are three numeric types in Python: + + # -> int + # -> float + # -> complex + + # Variables of numeric types are created when you assign a value to them: + + # -> Example +x = 1 # int +y = 2.8 # float +z = 1j # complex + + # To verify the type of any object in Python, use the type() function: + + # -> Example + +print(type(x)) +print(type(y)) +print(type(z)) + + # -> Output + # + # + # + + + # Integers: + + # Int, or integer, is a whole number, positive or negative, without decimals, of unlimited length. + + # -> Example + + +x = 1 +y = 35656222554887711 +z = -3255522 + +print(type(x)) +print(type(y)) +print(type(z)) + + # -> Output + # + # + # + + # Floats: + + # Float, or "floating point number" is a number, positive or negative, containing one or more decimals. + + # -> Example + +x = 1.10 +y = 1.0 +z = -35.59 + +print(type(x)) +print(type(y)) +print(type(z)) + + # -> Output + # + # + # + + # Float can also be scientific numbers with an "e" to indicate the power of 10. + + # -> Example + +x = 35e3 +y = 12E4 +z = -87.7e100 + +print(type(x)) +print(type(y)) +print(type(z)) + + # -> Output + # + # + # + + + # Complex: + + # Complex numbers are written with a "j" as the imaginary part: + + # -> Example + +x = 3+5j +y = 5j +z = -5j + +print(type(x)) +print(type(y)) +print(type(z)) + + # -> Output + # + # + # + + + +#************************************** +# # Python Casting: +# #************************************** + +# Specify a Variable Type + +# There may be times when you want to specify a type on to a variable. This can be done with casting. Python is an object-orientated language, and as such it uses classes to define data types, including its primitive types. + +# Casting in python is therefore done using constructor functions: + +# -> int() - constructs an integer number from an integer literal, a float literal (by rounding down to the previous whole number), or a string literal (providing the string represents a whole number) +# -> float() - constructs a float number from an integer literal, a float literal or a string literal (providing the string represents a float or an integer) +# -> str() - constructs a string from a wide variety of data types, including strings, integer literals and float literals + +# -> Example +# Integers: + +x = int(1) +y = int(2.8) +z = int("3") + + # -> Output + # 1 + # 2 + # 3 + + + # -> Example + # Floats: + +x = float(1) # x will be 1.0 +y = float(2.8) # y will be 2.8 +z = float("3") # z will be 3.0 +w = float("4.2") # w will be 4.2 + + + # -> Example + # Strings: + +x = str("s1") # x will be 's1' +y = str(2) # y will be '2' +z = str(3.0) # z will be '3.0' \ No newline at end of file