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Confused about a few lines code in a scala official document page


Confused about a few lines code in a scala official document page

By : user2955995
Date : November 22 2020, 10:48 AM
like below fixes the issue from and to are methods in class EdgeImpl. They both have zero parameters and a return type of Node. from isn't "assigned" the value of origin per-se. It's just a method that always returns origin.
Without reading too much into it, it can probably have just been made a val, but a method that returns a constant value is completely valid.
code :


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Samples of Scala and Java code where Scala code looks simpler/has fewer lines?

Samples of Scala and Java code where Scala code looks simpler/has fewer lines?


By : bierfout
Date : March 29 2020, 07:55 AM
I hope this helps . Let's improve stacker's example and use Scala's case classes:
code :
case class Person(firstName: String, lastName: String)
public class Person implements Serializable {
    private final String firstName;
    private final String lastName;

    public Person(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public Person withFirstName(String firstName) {
        return new Person(firstName, lastName);
    }

    public Person withLastName(String lastName) {
        return new Person(firstName, lastName);
    }

    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Person person = (Person) o;
        if (firstName != null ? !firstName.equals(person.firstName) : person.firstName != null) {
            return false;
        }
        if (lastName != null ? !lastName.equals(person.lastName) : person.lastName != null) {
            return false;
        }
        return true;
    }

    public int hashCode() {
        int result = firstName != null ? firstName.hashCode() : 0;
        result = 31 * result + (lastName != null ? lastName.hashCode() : 0);
        return result;
    }

    public String toString() {
        return "Person(" + firstName + "," + lastName + ")";
    }
}
Person mr = new Person("Bob", "Dobbelina");
Person miss = new Person("Roberta", "MacSweeney");
Person mrs = miss.withLastName(mr.getLastName());
val mr = Person("Bob", "Dobbelina")
val miss = Person("Roberta", "MacSweeney")
val mrs = miss copy (lastName = mr.lastName)
Code used in Ruby on rails official API document incorrect?

Code used in Ruby on rails official API document incorrect?


By : amber
Date : March 29 2020, 07:55 AM
seems to work fine Yes, this is wrong due to a bug in the RDoc parser that Rails uses. See here for more information: http://groups.google.com/group/rubyonrails-docs/browse_thread/thread/bc1ae76aa8179406.
Scala official documentation Variances example code

Scala official documentation Variances example code


By : user3822131
Date : March 29 2020, 07:55 AM
Hope that helps A is covariant so a Stack[C] is a subtype of Stack[B] since C is a subtype of B. The signature of push means that if you push a supertype of A, you will receive a Stack[Supertype]. This means pushing a B onto a Stack[C] will return a Stack[B]:
code :
val s = Stack[C]()
val bs: Stack[B] = s.push(new B(1))
val as: Stack[Any] = s.push(1)
how does this sentence(yield "lines", 1) work in mrjob's Official document

how does this sentence(yield "lines", 1) work in mrjob's Official document


By : Tharindu Wickcramara
Date : March 29 2020, 07:55 AM
Hope that helps This code returns a tuple: ("lines", 1). Parentheses can be omitted for tuples in situations like this. Each yield returns some aspect of the input, as well as the aspect's value. The number of lines is 1.
The line could have been written like this:
code :
yield ("lines", 1)
Function-type Variable declaration - typo on official golang document page

Function-type Variable declaration - typo on official golang document page


By : Jesper
Date : March 29 2020, 07:55 AM
may help you . At golang.org blog here we have the syntax to declare a function-type variable , Both are correct.
This:
code :
f func(func(int,int) int, int) func(int, int) int
f func(func(int,int) int, int) func(int, int)
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