JavaFX: TableView widget

TableView class is used to define a table view control. TableView represent the data in rows and columns.

 

Is TableView scrollable?

Yes

 

Is TableView editable?

Yes

 

TableColumn

 

Find the below working application.

 

TableViewDemo.java

package com.sample.app.widgets;

import com.sample.app.model.Person;

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.effect.DropShadow;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;

public class TableViewDemo extends Application {

	@Override
	public void start(Stage primaryStage) throws Exception {
		ObservableList<Person> emps = FXCollections.observableArrayList();

		emps.setAll(new Person(1, "Krishna"), new Person(2, "Ram"), new Person(3, "Joel"), new Person(4, "Gopi"),
				new Person(5, "Sharief"));

		Label label = new Label("Persons information");
		label.setFont(Font.font("Verdana", FontWeight.BOLD, 25));

		VBox vBox1 = new VBox(label);
		vBox1.setAlignment(Pos.CENTER);
		vBox1.setSpacing(20);

		VBox vBox2 = new VBox();

		TableColumn<Person, Integer> idColumn = new TableColumn<>("Id");
		idColumn.setMinWidth(50);
		idColumn.setCellValueFactory(new PropertyValueFactory<Person, Integer>("id"));

		TableColumn<Person, String> nameColumn = new TableColumn<>("Name");
		nameColumn.setMinWidth(50);
		nameColumn.setCellValueFactory(new PropertyValueFactory<Person, String>("name"));

		TableView<Person> tableView = new TableView<>();
		tableView.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
		tableView.setItems(emps);
		tableView.setPrefHeight(250);
		tableView.getColumns().add(idColumn);
		tableView.getColumns().add(nameColumn);
		tableView.setPadding(new Insets(20));
		tableView.setEditable(true);

		DropShadow dropShadow = new DropShadow();
		dropShadow.setOffsetX(5);
		dropShadow.setOffsetY(5);
		dropShadow.setColor(Color.GRAY);

		tableView.setEffect(dropShadow);

		vBox2.getChildren().add(tableView);

		HBox hBox = new HBox();
		hBox.setSpacing(25);
		Label nameLabel = new Label("Change person name");
		nameLabel.setFont(Font.font("Verdana", 20));

		TextField textField = new TextField();

		textField.setOnAction(event -> {
			Person person = tableView.getSelectionModel().getSelectedItem();
			person.setName(textField.getText());
			tableView.refresh();
		});

		hBox.getChildren().addAll(nameLabel, textField);

		VBox buttonVBox = new VBox();
		buttonVBox.setAlignment(Pos.CENTER);
		Button removePerson = new Button("Remove");
		removePerson.setFont(Font.font("Verdana", 20));
		removePerson.setOnAction(event -> {
			Person person = tableView.getSelectionModel().getSelectedItem();
			tableView.getItems().remove(person);
			tableView.refresh();
		});
		buttonVBox.getChildren().add(removePerson);

		VBox vBox = new VBox(vBox1, vBox2, hBox, buttonVBox);
		vBox.setStyle("-fx-background-color:lightyellow");
		vBox.setPadding(new Insets(20));
		vBox.setSpacing(20);

		Scene scene = new Scene(vBox, 600, 500, Color.WHITE);

		primaryStage.setTitle("TableView Demo");
		primaryStage.setScene(scene);
		primaryStage.show();

	}

	public static void main(String args[]) {
		launch(args);
	}
}

 

Output

  

 

Select a row and add some name in text field and enter, you will see new name will be reflected.

 

Select a row and click on Remove button, you will see that the row is deleted.

 

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Python: Remove all the instances of a value from list

Using ‘while’ loop, we can delete all the instances of a value from the list.

 

Example

def remove_element(item, list):

    while(item in list):

         list.remove(item)

 

remove_elements.py

def remove_element(item, list):
    while(item in list):
    	list.remove(item)

data = [1, 2, 3, 4, 5, 3, 2, 2, 3, 4, 3]
print(f"data : {data}")

print("\nRemoving 3 from list")

remove_element(3, data)
print(f"\ndata : {data}")

 

Output

$python3 remove_elements.py
data : [1, 2, 3, 4, 5, 3, 2, 2, 3, 4, 3]

Removing 3 from list

data : [1, 2, 4, 5, 2, 2, 4]

 

 

  

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Python: Convert string to an integer

‘int(string)’ function takes a string as argument and convert it to an integer.

>>> data = "2345"
>>> 
>>> data
'2345'
>>> 
>>> int(data)
2345

 

You will get an error while converting non-numerical data.

>>> data = "hh"
>>> 
>>> int(data)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: 'hh'

 

 

 

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Python: Dictionary in a dictionary

dict_in_dict.py

country_capitals = {"India" : "New Delhi", "Bangladesh" : "Dhaka", "France" : "Paris"}
numbers = {1 : "One", 2: "Two"}

my_dictionary = {"countryCapitals": country_capitals, "numbers" : numbers}

for key in my_dictionary.keys():
	print(f"{key} -> {my_dictionary[key]}")

 

Output

$ python3 dict_in_dict.py 
countryCapitals -> {'India': 'New Delhi', 'Bangladesh': 'Dhaka', 'France': 'Paris'}
numbers -> {1: 'One', 2: 'Two'}

 

 

 

 

 

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Python: List in a dictionary

In this post, I am going to explain how to add a list to the dictionary.

 

list_in_dictionary.py

dict = {1 : "One"}
even_numbers = [2, 4, 6, 8]
odd_numbers = [1, 3, 5, 7]

my_dictionary = {"dict": dict, "evenNumbers" : even_numbers, "oddNumbers" : odd_numbers}

for key in my_dictionary.keys():
	print(f"{key} -> {my_dictionary[key]}")

 

This Python snippet initializes three separate variables: a dictionary named dict with the key-value pair {1: "One"}, a list named even_numbers containing even integers [2, 4, 6, 8], and another list named odd_numbers containing odd integers [1, 3, 5, 7]. Subsequently, a new dictionary named my_dictionary is created, where each key corresponds to a different variable, linking the names 'dict', 'evenNumbers', and 'oddNumbers' to their respective values.

 

The snippet then employs a for loop to iterate through the keys of my_dictionary. Within each iteration, it prints a formatted string indicating the key and its associated value. This loop effectively showcases the contents of my_dictionary by displaying each key-value pair.

 

Output

$ python3 list_in_dictionary.py 
dict -> {1: 'One'}
evenNumbers -> [2, 4, 6, 8]
oddNumbers -> [1, 3, 5, 7]

 

 

 

 

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Python: List of dictionaries

In this post, I am going to explain how to create list of dictionaries.

 

list_of_dictionary.py

dict1 = {"a" : "A", "b" : "B"}
dict2 = {1 : "One", 2 : "Two"}
country_capitals = {"India" : "New Delhi", "Bangladesh" : "Dhaka", "France" : "Paris"}

list = [dict1, dict2, country_capitals]

for item in list:
	print(f"{item}")

Output

$ python3 list_of_dictionary.py {'a': 'A', 'b': 'B'} {1: 'One', 2: 'Two'} {'India': 'New Delhi', 'Bangladesh': 'Dhaka', 'France': 'Paris'}

 

 

 

 

 

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Python: Looping through all values in a dictionary

‘values’ method is used to loop through all the values in a dictionary.

>>> country_capitals = {"India" : "New Delhi", "Bangladesh" : "Dhaka", "France" : "Paris"}
>>> 
>>> for capital in country_capitals.values():
...   print(f"{capital}")
... 
New Delhi
Dhaka
Paris

 

 

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Python: Looping through the dictionary in the sorted order of keys

Using ‘sorted’ and ‘keys’ methods, you can loop through the dictionary in the sorted order of dictionary keys.

>>> country_capitals = {"India" : "New Delhi", "Bangladesh" : "Dhaka", "France" : "Paris"}
>>> 
>>> for country in sorted(country_capitals):
...    print(f"{country} -> {country_capitals[country]}")
... 
Bangladesh -> Dhaka
France -> Paris
India -> New Delhi

 

 

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Python: Looping over a dictionary using keys

Using keys() method

‘keys()’ method return an iterator over all the keys of a dictionary.

 

Example

for key in emps.keys():

    print(f"{key} : {emps[key]}")

>>> emps = {1: {'Hari Krishna', 'Gurram'}, 3: {'Shekkappa', 'Mohan'}, 4: {'Ranganath', 'Thippisetty'}, 5: {'Ganji', 'Sudheer'}}
>>> 
>>> for key in emps.keys():
...   print(f"{key} : {emps[key]}")
... 
1 : {'Gurram', 'Hari Krishna'}
3 : {'Mohan', 'Shekkappa'}
4 : {'Thippisetty', 'Ranganath'}
5 : {'Sudheer', 'Ganji'}

 

 

 

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Python: Check list emptiness using if condition

‘if list_name’

 

Syntax

if list_name:
    # List is not empty
else:
   # List is empty

 

Example

if list:
	for elem in list:
		print(elem)
	else:
		print("List is empty\n")

 

list_emptycheck.py

# Print elements of list
def print_elements(list):
   if list:
      for elem in list:
         print(elem)
   else:
      print("List is empty\n")

primes = []
print_elements(primes)

primes.append(2)
primes.append(3)
primes.append(5)
print_elements(primes)

Output

$ python3 list_empty_check.py 
List is empty

2
3
5

 

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