accessor

问题 I am working on a homework assignment. I am confused on how it should be done. The question is: Create a class called IDCard that contains a person\'s name, ID number, and the name of a file containing the person\'s photogrpah. Write accessor and mutator methods for each of these fields. Add the following two overloaded constructors to the class: public IDCard() public IDCard(String n, int ID, String filename) Test your program by creating different ojbects using these two constructors and

问题 I am trying to create a constructor that takes a field as a parameter, then puts it in a field that is stored in a superclass. Here is the code I am using public crisps(String flavour, int quantity) { this.flavour = super.getFlavour(); this.quantity = quantity; } In the superclass I have initialised the field with private String flavour; and I have an accessor method public String getFlavour() { return flavour; } I am getting an error \" flavour has private access in the superclass \", but I

问题 I read a csv file containing 150,000 lines into a pandas dataframe. This dataframe has a field, \'Date\', with the dates in yyyy-mm-dd format. I want to extract the month, day and year from it and copy into the dataframes\' columns, \'Month\', \'Day\' and \'Year\' respectively. For a few hundred records the below two methods work ok, but for 150,000 records both take a ridiculously long time to execute. Is there a faster way to do this for 100,000+ records? First method: df = pandas.read_csv

问题 I would like to be able to write a Java class in one package which can access non-public methods of a class in another package without having to make it a subclass of the other class. Is this possible? 回答1: Here is a small trick that I use in JAVA to replicate C++ friend mechanism. Lets say I have a class Romeo and another class Juliet . They are in different packages (family) for hatred reasons. Romeo wants to cuddle Juliet and Juliet wants to only let Romeo cuddle her. In C++, Juliet would

问题 This question already has answers here : Why use getters and setters/accessors? (38 answers) Closed 4 years ago . I\'m currently working on a simple game in Java with several different modes. I\'ve extended a main Game class to put the main logic within the other classes. Despite this, the main game class is still pretty hefty. After taking a quick look at my code the majority of it was Getters and Setters (60%) compared to the rest that is truly needed for the logic of the game. A couple of