Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings

Commit 2c2571b

Browse files
author
Rajeev Kumar Singh
committed
Initial Commit
0 parents commit 2c2571b

File tree

50 files changed

+1383
-0
lines changed

Some content is hidden

Large Commits have some content hidden by default. Use the searchbox below for content that may be hidden.

50 files changed

+1383
-0
lines changed

‎.DS_Store

6 KB
Binary file not shown.

‎.gitignore

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
.idea
2+
*.class
3+
*.iml

‎Readme.md

Whitespace-only changes.

‎java-arraylist-examples/.gitignore

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
.idea
2+
*.class
3+
*.iml

‎java-arraylist-examples/Readme.md

Whitespace-only changes.
Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,34 @@
1+
import java.util.ArrayList;
2+
import java.util.List;
3+
4+
public class AccessElementsFromArrayListExample {
5+
public static void main(String[] args) {
6+
List<String> topCompanies = new ArrayList<>();
7+
8+
// Check if an ArrayList is empty
9+
System.out.println("Is the topCompanies list empty? : " + topCompanies.isEmpty());
10+
11+
topCompanies.add("Google");
12+
topCompanies.add("Apple");
13+
topCompanies.add("Microsoft");
14+
topCompanies.add("Amazon");
15+
topCompanies.add("Facebook");
16+
17+
// Find the size of an ArrayList
18+
System.out.println("Here are the top " + topCompanies.size() + " companies in the world");
19+
System.out.println(topCompanies);
20+
21+
// Retrieve the element at a given index
22+
String bestCompany = topCompanies.get(0);
23+
String secondBestCompany = topCompanies.get(1);
24+
String lastCompany = topCompanies.get(topCompanies.size() - 1);
25+
26+
System.out.println("Best Company: " + bestCompany);
27+
System.out.println("Second Best Company: " + secondBestCompany);
28+
System.out.println("Last Company in the list: " + lastCompany);
29+
30+
// Modify the element at a given index
31+
topCompanies.set(4, "Walmart");
32+
System.out.println("Modified top companies list: " + topCompanies);
33+
}
34+
}
Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
1+
import java.util.ArrayList;
2+
import java.util.Collections;
3+
import java.util.List;
4+
5+
public class ArrayListCollectionsSortExample {
6+
public static void main(String[] args) {
7+
List<Integer> numbers = new ArrayList<>();
8+
numbers.add(13);
9+
numbers.add(7);
10+
numbers.add(18);
11+
numbers.add(5);
12+
numbers.add(2);
13+
14+
System.out.println("Before : " + numbers);
15+
16+
// Sorting an ArrayList using Collections.sort() method
17+
Collections.sort(numbers);
18+
19+
System.out.println("After : " + numbers);
20+
}
21+
}
Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
import java.util.ArrayList;
2+
import java.util.Iterator;
3+
import java.util.List;
4+
5+
public class ArrayListIteratorRemoveExample {
6+
public static void main(String[] args) {
7+
List<Integer> numbers = new ArrayList<>();
8+
numbers.add(13);
9+
numbers.add(18);
10+
numbers.add(25);
11+
numbers.add(40);
12+
13+
Iterator<Integer> numbersIterator = numbers.iterator();
14+
while (numbersIterator.hasNext()) {
15+
Integer num = numbersIterator.next();
16+
if(num % 2 != 0) {
17+
numbersIterator.remove();
18+
}
19+
}
20+
21+
System.out.println(numbers);
22+
}
23+
}
Lines changed: 64 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,64 @@
1+
import java.util.ArrayList;
2+
import java.util.Collections;
3+
import java.util.Comparator;
4+
import java.util.List;
5+
6+
class Person {
7+
private String name;
8+
private Integer age;
9+
10+
public Person(String name, Integer age) {
11+
this.name = name;
12+
this.age = age;
13+
}
14+
15+
public String getName() {
16+
return name;
17+
}
18+
19+
public void setName(String name) {
20+
this.name = name;
21+
}
22+
23+
public Integer getAge() {
24+
return age;
25+
}
26+
27+
public void setAge(Integer age) {
28+
this.age = age;
29+
}
30+
31+
@Override
32+
public String toString() {
33+
return "{" +
34+
"name='" + name + '\'' +
35+
", age=" + age +
36+
'}';
37+
}
38+
}
39+
40+
public class ArrayListObjectSortExample {
41+
public static void main(String[] args) {
42+
List<Person> people = new ArrayList<>();
43+
people.add(new Person("Sachin", 47));
44+
people.add(new Person("Chris", 34));
45+
people.add(new Person("Rajeev", 25));
46+
people.add(new Person("David", 31));
47+
48+
System.out.println("Person List : " + people);
49+
50+
// Sort People by their Age
51+
people.sort((person1, person2) -> {
52+
return person1.getAge() - person2.getAge();
53+
});
54+
55+
// A more concise way of writing the above sorting function
56+
people.sort(Comparator.comparingInt(Person::getAge));
57+
58+
System.out.println("Sorted Person List by Age : " + people);
59+
60+
// You can also sort using Collections.sort() method by passing the custom Comparator
61+
Collections.sort(people, Comparator.comparing(Person::getName));
62+
System.out.println("Sorted Person List by Name : " + people);
63+
}
64+
}
Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,31 @@
1+
import java.util.ArrayList;
2+
import java.util.Comparator;
3+
import java.util.List;
4+
5+
public class ArrayListSortExample {
6+
public static void main(String[] args) {
7+
List<String> names = new ArrayList<>();
8+
names.add("Lisa");
9+
names.add("Jennifer");
10+
names.add("Mark");
11+
names.add("David");
12+
13+
System.out.println("Names : " + names);
14+
15+
// Sort an ArrayList using its sort() method. You must pass a Comparator to the ArrayList.sort() method.
16+
names.sort(new Comparator<String>() {
17+
@Override
18+
public int compare(String name1, String name2) {
19+
return name1.compareTo(name2);
20+
}
21+
});
22+
23+
// The above `sort()` method call can also be written simply using lambda expressions
24+
names.sort((name1, name2) -> name1.compareTo(name2));
25+
26+
// Following is an even more concise solution
27+
names.sort(Comparator.naturalOrder());
28+
29+
System.out.println("Sorted Names : " + names);
30+
}
31+
}

0 commit comments

Comments
(0)

AltStyle によって変換されたページ (->オリジナル) /