Tag: key
Python: Iterate over a dictionary sorted by key
In this article, we will learn different ways to iterate over a python dictionary sorted by key in both the assending and descending order. Table of Contents: Iterate over a python dictionary sorted by key using sorted(). Iterate over dictionary sorted by keys using items(). Iterate over dictionary sorted by key using comparator / lambda …
MySQL ADD FOREIGN KEY
This article will discuss how to add foreign keys while creating a table and to existing tables. Table of Contents:- Add foreign key while creating a table in MySQL Add foreign key to an existing table in MySQL Add foreign key while creating a table in MySQL We will be creating a table named student_details and inserting some rows …
MySQL add primary key to existing table
This article will look into adding a primary key to an existing table with and without data. We will be illustrating the concept using different examples. Table of Contents:- MySQL add primary key to existing empty table MySQL add primary key to existing table with data Let us get started by preparing the sample data. …
Javascript: Get Key by Value
While working in javascript, often there is a requirement to get the key of an object for a particular value. This article will discuss accessing the key of a javascript object by value. Table of Contents:- Get key by value using loop Get key by value using Object.keys() and Object.values() Get key by value using …
Javascript: Check if key exists in Object (4 ways)
While working in javascript, there is often a requirement to determine if a key exists in a particular object. This article demonstrates easy ways to check if a key exists in a javascript object using different methods and example illustrations. Table of Contents: Check if key exists in javascript Object using in operator Check if …
Python | Add to Dictionary If Key doesn’t exist
This article will discuss how to add key-value pairs in the dictionary only when Key does not exist. Add a key-value pair to the dictionary if Key doesn’t exist Suppose we have a dictionary of string and integers, # Dictionary of strings and ints word_freq = {“Hello”: 56, “at”: 23, “test”: 43, “this”: 43} Now, …
JavaScript: How to get value by key
While working in javascript, often there is a requirement to get the value of an object for a particular key. This article will discuss accessing the value of a javascript object by key. There are two easy ways to get the value corresponding to the key of an object First using square brackets ‘[ ]‘ …
Check if an Array contains a key in PHP
This tutorial will discuss about unique ways to check if an array contains a key in php. Table Of Contents Method 1: Using array_key_exists() function Method 2: Using isset() function Summary Method 1: Using array_key_exists() function The array_key_exists() function in PHP, accepts a key and an array as arguments, and returns true, if the given …
MySQL add primary key multiple columns
This article will add a primary key to multiple columns while creating a table and existing tables with data. We will be illustrating the concept using different examples. Table of Contents:- Add primary key multiple columns to new table Add primary key multiple columns to existing table with data and existing primary key Primary keys …
How to disable foreign key constraint in MySQL
In this article, we will see how to disable foreign key constraints temporarily in MySQL. It is not a good idea to disable the foreign key constraint to remove the errors that occur. Foreign keys are there to maintain data integrity. Still, in many cases, we need to disable the foreign key constraint, for example, …