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Both List and Tuple are called as sequence data types of Python. Objects of both types are comma separated collection of items not necessarily of same type.SimilaritiesConcatenation, repetition, indexing and slicing can be done on objects of both types>>> #list operations >>> L1=[1, 2, 3] >>> L2=[4, 5, 6] >>> #concatenation >>> L3=L1+L2 >>> L3 [1, 2, 3, 4, 5, 6] >>> #repetition >>> L1*3 [1, 2, 3, 1, 2, 3, 1, 2, 3] >>> #indexing >>> L3[4] 5 >>> #slicing >>> L3[2:4] [3, 4]>>> #tuple operations >>> T1=(1, 2, 3) >>> T2=(4, 5, 6) >>> #concatenation >>> T3=T1+T2 >>> ... Read More
Python sequence, including list object allows indexing. Any element in list can be accessed using zero based index. If index is a negative number, count of index starts from end. As we want second to last element in list, use -2 as index.>>> L1=[1,2,3,4,5] >>> print (L1[-2]) 4
The getattr() methodThe getattr() method returns the value of the named attribute of an object. If not found, it returns the default value provided to the function.SyntaxThe syntax of getattr() method is −getattr(object, name[, default])The getattr() method can take multiple parameters −The getattr() method returns −value of the named attribute of the given objectdefault, if no named attribute is foundAttributeError exception, if named attribute is not found and default is not definedThe setattr() methodThe setattr() method sets the value of given attribute of an object.SyntaxThe syntax of setattr() method is −setattr(object, name, value)The setattr() method takes three parameters −The setattr() ... Read More
Python delattr()The delattr() deletes an attribute from the object if the object allows it.SyntaxThe syntax of delattr() is −delattr(object, name)The delattr() method takes two parameters −The delattr() doesn't return any value (returns None). It only removes an attribute (if object allows it).Exampleclass Coordinate: x = 12 y = -7 z = 0 point1 = Coordinate() print('x = ', point1.x) print('y = ', point1.y) print('z = ', point1.z) delattr(Coordinate, 'z') print('--After deleting z attribute--') print('x = ', point1.x) print('y = ', point1.y) # Raises Error ... Read More
The setattr() methodThe setattr() method sets the value of given attribute of an object.SyntaxThe syntax of setattr() method is −setattr(object, name, value)The setattr() method takes three parameters −The setattr() method returns None.Exampleclass Male: name = 'Abel' x = Male() print('Before modification:', x.name) # setting name to 'Jason' setattr(x, 'name', 'Jason') print('After modification:', x.name)OutputThis gives the output('Before modification:', 'Abel') ('After modification:', 'Jason')
Class variables are variables that are declared outside the__init__method. These are static elements, meaning, they belong to the class rather than to the class instances. These class variables are shared by all instances of that class. Example code for class variables Exampleclass MyClass: __item1 = 123 __item2 = "abc" def __init__(self): #pass or something elseYou'll understand more clearly with more code −class MyClass: stat_elem = 456 def __init__(self): self.object_elem = 789 c1 = MyClass() c2 = MyClass() # Initial values of both elements >>> print c1.stat_elem, c1.object_elem 456 ... Read More
Attributes of a classEverything, almost everything in Python is an object. Every object has attributes and methods. Thus attributes are very fundamental in Python. A class is a construct which is a collection of similar objects. A class also has attributes. There will be a difference between the class attributes and instance attributes. The class attributes are shared by the instances of the class but it not true vice versa.ExampleWe can get a list of the attributes of an object using the built-in “dir” function. For example −>>> s = 'abc' >>> len(dir(s)) 71 >>> dir(s)[:5] ['__add__', '__class__', '__contains__', '__delattr__', ... Read More
Cast operator in java is used to convert one data type to other.Examplepublic class Sample { public static void main(String args[]) { double d = 20.3; int i = (int)d; System.out.println(i); } }Output20
The instanceof operator is used only for object reference variables. The operator checks whether the object is of a particular type (class type or interface type).Examplepublic class Test { public static void main(String args[]) { String name = "James"; boolean result = name instanceof String; System.out.println(result); } }Outputtrue
The conditional operator is also known as the ternary operator. This operator consists of three operands and is used to evaluate Boolean expressions. The goal of the operator is to decide; which value should be assigned to the variable. The operator is written as:variable x = (expression)? value if true: value if falseExamplepublic class Test { public static void main(String args[]) { int a, b; a = 10; b = (a == 1) ? 20: 30; System.out.println("Value of b is: " + b); b = (a == 10) ? 20: 30; System.out.println(“Value of b is: " + b); } }OutputValue of b is: 30 Value of b is: 20