In JavaScript, .contains() and .includes() are used for different purposes:
.contains(): This is a method of the Node interface in the Document Object Model (DOM). It’s used to check whether a node is a descendant of a given node, i.e., child, grandchild, etc.
node.contains(otherNode)
.includes(): This is a method of the Array and String prototypes in JavaScript. It’s used to determine whether an array includes a certain value among its entries or whether a string includes a certain substring.
For arrays:
array.includes(valueToFind, fromIndex)
For strings:
string.includes(searchString, position)
So, the main difference is that .contains() is used with DOM nodes, while .includes() is used with arrays and strings.
# String Concatenationname = "John"age = 25print("Hello, my name is " + name + " and I am " + str(age) + " years old.")# String Interpolationname = "John"age = 25print(f"Hello, my name is {name} and I am {age} years old.")# String Interpolation with format()name = "John"age = 25print("Hello, my name is {} and I am {} years old.".format(name, age))# String Interpolation with format() and positional argumentsname = "John"age = 25print("Hello, my name is {0} and I am {1} years old.".format(name, age))# String Interpolation with format() and keyword argumentsname = "John"age = 25print("Hello, my name is {name} and I am {age} years old.".format(name=name, age=age))# String Interpolation with format() and mixed argumentsname = "John"age = 25print("Hello, my name is {0} and I am {age} years old.".format(name, age=age))
# for loops# About for loops# for loops are used to iterate over a sequence (list, tuple, string) or other # iterable objects.# Syntax# for variable in sequence:# code block# Examples# Iterate over a list# A list is a collection which is ordered and changeable.print("\nIterate over a list")fruits = ["apple", "banana", "cherry"]for fruit in fruits:print(fruit)# Output# apple# banana# cherry# Iterate over a string# A string is a sequence of charactersprint("\nIterate over a string")for letter in"apple":print(letter)# Output# a# p# p# l# e# Iterate over a range# A range is a sequence of numbers, starting from 0 by default, and incrementsprint("\nIterate over a range")for i inrange(5):print(i)# Output# 0# 1# 2# 3# 4# Note: The range() function returns a sequence of numbers, starting from 0 # by default, and increments by 1 (by default), and stops before a # specified number.# Iterate over a tuple# A tuple is a collection which is ordered and unchangeable.print("\nIterate over a tuple")colors = ("red", "green", "blue")for color in colors:print(color)# Output# red# green# blue# Iterate over a dictionary# A dictionary is a collection which is unordered, changeable and indexed.print("\nIterate over a dictionary")person = {"name": "Alice","age": 25,"is_active": True}for key in person:print(key, person[key])# Output# name Alice# age 25# is_active True# Note: The for loop iterates over the keys of the dictionary.# Iterate over a dictionary using items() method# The items() method returns a view object that displays a list of a given# dictionary's key-value tuple pair.print("\nIterate over a dictionary using items() method")for key, value in person.items():print(key, value)# Output# name Alice# age 25# is_active True# Note: The for loop iterates over the key-value pairs of the dictionary.if key == "age"and value >= 18:print(person["name"], "is an adult.")# Iterate over a dictionary using values() method# The values() method returns a view object that displays a list of all the# values in the dictionary.print("\nIterate over a dictionary using values() method")for value in person.values():print(value)# Output# Alice# 25# True# Note: The for loop iterates over the values of the dictionary.# Iterate over a dictionary using keys() method# The keys() method returns a view object that displays a list of all the keys# in the dictionary.print("\nIterate over a dictionary using keys() method")for key in person.keys():print(key)# Output# name# age# is_active# Note: The for loop iterates over the keys of the dictionary.# Iterate over a dictionary using get() method# The get() method returns the value of the specified key.print("\nIterate over a dictionary using get() method")print(person.get("name"))# Nested for loops# clientsclients = [ {"name": "Alice", "age": 25}, {"name": "Bob", "age": 30}, {"name": "Charlie", "age": 35}]# productsproducts = ["apple", "banana", "cherry"]inventory = {"apple": 10,"banana": 20,"cherry": 30}# ordersorders = [ {"client": "Alice", "product": "apple"}, {"client": "Bob", "product": "banana"}, {"client": "Charlie", "product": "cherry"}]# Iterate over clientsprint("\nIterate over clients")for client in clients:print(client["name"], client["age"])# Output# Alice 25# Bob 30# Charlie 35# Iterate over productsprint("\nIterate over products")for product in products:print(product)# Output# apple# banana# cherry# Iterate over ordersprint("\nIterate over orders")for order in orders:print(order["client"], order["product"])# Output# Alice apple# Bob banana# Charlie cherry# Iterate over orders and products and update inventoryprint("\nIterate over orders and products and update inventory")for order in orders:for product in products:if order["product"] == product: inventory[product] -= 1print(order["client"], "ordered", order["product"])print("Inventory of", product, "is", inventory[product])# Output# Alice ordered apple# Inventory of apple is 9# Bob ordered banana# Inventory of banana is 19# Charlie ordered cherry# Inventory of cherry is 29# Note: The nested for loop iterates over the orders and products and updates# the inventory of the products.
-- Create a new database-- This creates a new database named "sandbox". This is not necessary if you already have a database to work with.CREATEDATABASEdatabase_name;-- Use a specific database-- This selects the "sandbox" database for use. Replace "sandbox" with the name of the database you want to use.USEdatabase_name;-- Create a new table-- This creates a new table named "table_name" with columns "column1" and "column2" of data types "datatype1" and "datatype2" respectively. Replace "table_name", "column1", "column2", "datatype1", and "datatype2" with the desired names and data types.CREATETABLEtable_name ( column1 datatype, column2 datatype, ...);-- Insert data into a table-- This inserts a new row into the "table_name" table with values "value1" and "value2" for columns "column1" and "column2" respectively. Replace "table_name", "column1", "column2", "value1", and "value2" with the desired table name, column names, and values.INSERT INTO table_name (column1, column2, ...)VALUES (value1, value2, ...);-- Select all rows from a table-- This selects all rows from the "table_name" table. Replace "table_name" with the name of the table you want to select from.SELECT * FROM table_name;-- Select specific columns from a table-- This selects specific columns "column1" and "column2" from the "table_name" table. Replace "column1", "column2", and "table_name" with the desired column names and table name.SELECT column1, column2, ... FROM table_name;-- Filter rows using WHERE clause-- This selects all rows from the "table_name" table where the condition is met. Replace "table_name" with the name of the table you want to select from and "condition" with the desired condition.SELECT * FROM table_name WHERE condition;-- Update data in a table-- This updates the "column1" and "column2" columns in the "table_name" table with new values "value1" and "value2" where the condition is met. Replace "table_name", "column1", "column2", "value1", "value2", and "condition" with the desired table name, column names, values, and condition.UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;-- Delete data from a table-- This deletes rows from the "table_name" table where the condition is met. Replace "table_name" with the name of the table you want to delete from and "condition" with the desired condition.DELETEFROM table_name WHERE condition;-- Join two or more tables-- This joins the "table1" and "table2" tables on the "column" column. Replace "table1", "table2", and "column" with the names of the tables and column you want to join on.SELECT * FROM table1 JOIN table2 ON table1.column = table2.column;-- Order rows in ascending or descending order-- This selects all rows from the "table_name" table and orders them in ascending or descending order based on the "column" column. Replace "table_name" and "column" with the name of the table and column you want to order by, and "ASC" or "DESC" with the desired order.SELECT * FROM table_name ORDER BY column ASC/DESC;-- Limit the number of rows returned-- This selects the first "number" rows from the "table_name" table. Replace "table_name" with the name of the table you want to select from and "number" with the desired number of rows.SELECT * FROM table_name LIMITnumber;-- Group rows and perform aggregate functions-- This groups rows in the "table_name" table by the "column" column and counts the number of rows in each group. Replace "table_name" and "column" with the name of the table and column you want to group by.SELECT column, COUNT(*) FROM table_name GROUP BY column;-- Create an index on a table-- This creates an index named "index_name" on the "column" column in the "table_name" table. Replace "index_name", "table_name", and "column" with the desired index name, table name, and column.CREATEINDEXindex_nameON table_name (column);-- Drop a table-- This drops the "table_name" table. Replace "table_name" with the name of the table you want to drop. This is a destructive operation and cannot be undone.DROPTABLE table_name;-- Drop a database-- This drops the "database_name" database. Replace "database_name" with the name of the database you want to drop. This is a destructive operation and cannot be undone.DROPDATABASEdatabase_name;-- Show all databasesSHOW DATABASES;-- Show all tables in a databaseSHOW TABLES;-- Show the structure of a table-- This shows the columns, data types, and other information about the "table_name" table. Replace "table_name" with the name of the table you want to show the structure of.DESC table_name;-- Show the indexes on a table-- This shows the indexes on the "table_name" table. Replace "table_name" with the name of the table you want to show the indexes of.SHOW INDEXFROM table_name;-- Show the status of the server-- This shows various status information about the server, such as the number of connections, queries, and other statistics.SHOW STATUS;-- Show the current userSELECT USER();-- Show the current databaseSELECTDATABASE();-- Show the version of MySQLSELECTVERSION();-- Show the current date and timeSELECTNOW();-- Show the current time zoneSELECT @@time_zone;-- Join two or more tables-- This joins the "table1" and "table2" tables on the "column" column.-- A join combines rows from two or more tables based on a related column between them.SELECT * FROM table1 JOIN table2 ON table1.column = table2.column;-- Left join two or more tables-- This left joins the "table1" and "table2" tables on the "column" column.-- A left join returns all rows from the left table and the matched rows from the right table.SELECT * FROM table1 LEFT JOIN table2 ON table1.column = table2.column;-- Right join two or more tables-- This right joins the "table1" and "table2" tables on the "column" column.-- A right join returns all rows from the right table and the matched rows from the left table.SELECT * FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;-- Full outer join two or more tables-- This full outer joins the "table1" and "table2" tables on the "column" column.-- A full outer join returns all rows when there is a match in either the left or right table.SELECT * FROM table1 FULL OUTER JOIN table2 ON table1.column = table2.column;-- Cross join two or more tables-- This cross joins the "table1" and "table2" tables.-- A cross join returns the Cartesian product of the two tables, i.e., all possible combinations of rows.SELECT * FROM table1 CROSS JOIN table2;
While instance properties can be determined at launch, some of them can be updated after the instance has been created. Specifically, an instance’s memory, disk space, and the number of its CPUs are exposed via daemon settings: local..(cpus|disk|memory).
