Class (static) Variables and Methods
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Python |
Java |
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Class variables name
data that are shared by all instances of a class. A class variable is
introduced by a simple assignment statement within a class. Class variable
references are always prefixed with the name of the class. Class variables are
spelled in uppercase by convention. Example: class Student: NUM_GRADES = 5 def __init__(self, name):
self.name = name
self.grades = []
for i in range(Student.NUM_GRADES):
self.grades.append(0) Other usage: print
Student.NUM_GRADES Class methods are methods that know nothing about instances of
a class, but can access class variables and call other class methods for
various purposes. For example, a
method to convert a numeric grade to a letter grade might be defined as a
class method in the Student class. Class method calls are
always prefixed with the name of the class. Example: class Student: # Instance method
definitions @classmethod def getLetterGrade(cls,
grade):
if grade > 89:
return 'A'
elif grade > 79:
return 'B'
else:
return 'F' Usage: s = Student() for i in
range(1, Student.NUM_GRADES + 1): print Student.getLetterGrade(s.getGrade(i)) |
Class variables name
data that are shared by all instances of a class. A class variable
declaration is qualified by the reserved word static. Outside of the class
definition, class variable references are prefixed with the name of the
class. Class variables are
spelled in uppercase by convention. Example: public class
Student{ public static final int
NUM_GRADES = 5; private String name; private int[] grades; public Student(String
name){
this.name = name;
this.grades = new int[NUM_GRADES]; } } Other usage: System.out.println(Student.NUM_GRADES); Class methods are methods that know nothing about instances of
a class, but can access class variables and call other class methods for
various purposes. For example, a
method to convert a numeric grade to a letter grade might be defined as a
class method in the Student class. A class method header is
qualified by the reserved word static. Outside of the class
definition, class method calls are prefixed with the name of the class. Example: public class
Student{ // Instance method
definitions and variable declarations public static char
getLetterGrade(int grade){
if (grade > 89)
return 'A';
else if (grade > 79)
return 'B';
else
return 'F'; Usage: s = new
Student(); for (int i = 1;
i <= Student.NUM_GRADES; i++)
System.out.println(Student.getLetterGrade(s.getGrade(i)); |