Merge dictionaries in Python

By -

Merge dictionaries in Python with update()



address = {'street': 'MG Road', 'house': '123'}

contact = {'country': 'India', 'city': 'Indore', 'street': 'Ring Road'}

address.update(contact)

# Address dictionary will now have the updated data 

{'house': '123', 'country': 'India', 'city': 'Indore', 'street': 'Ring Road'}

We can use update() when we are required to merge two dictionaries in Python

address.update(contact), the key-value pairs of contact(dictionary2) will be written into the address(dictionary1).And for keys in both dictionary1 and dictionary2, the value in dictionary1 will be overwritten by the corresponding value in dictionary2

Comments

Post a Comment

Popular posts from this blog

Inserting and Moving elements inside Ruby Array

By -
Here's is an array with 5 elements 2.1.2 :001 > arr = ["a", "b", "c", "d", "e"] => ["a", "b", "c", "d", "e"] Lets look at few different cases Insert a new element at starting position Using unshift 2.1.2 :002 > arr.unshift("f") => ["f", "a", "b", "c", "d", "e"] Using insert 2.1.2 :005 > arr.insert(0, "f") => ["f", "a", "b", "c", "d", "e"] In the above example 0 is the position(index) Move existing element from one position to another The element in this case is "e" Using uniq to show only unique elements 2.1.2 :009 > arr.insert(0, "e").uniq => ["e", "a", "b", "c", "d"] With uniq we are only showing unique records but the element is listed
Read more

Difference between Validations, Callbacks and Observers

By -
Validations allow you to ensure that only valid data is stored in your database. Example: validates_presence_of :user_name, :password validates_numericality_of :value We can write custom validation also as def validate   errors.add(:price, “should be a positive value”) if price.nil?|| price < 0.01 end Callbacks and observers allow you to trigger logic before or after an alteration of an object’s state. Callbacks are methods that get called at certain moments of an object’s life cycle. With callbacks it’s possible to write code that will run whenever an Active Record object is created, saved, updated, deleted, validated, or loaded from the database. Callbacks are hooks into the life cycle of an Active Record object that allow you to trigger logic before or after an alteration of the object state. This can be used to make sure that associated and dependent objects are deleted when destroy is called (by overwriting before_destroy) or to massage attribu
Read more