How to update a Python dictionary values?

In Python, a Dictionary is one of the data structures that contains key-value pairs enclosed in curly braces '{}'. It is a Mutable and ordered data structure.

Before proceeding with updating the values of a dictionary, let's create an example Dictionary with 4 key-value pairs, in which Product, Model, Units, are keys of the Dictionary -

# Creating a Dictionary with 4 key-value pairs
myprod = {
    "Product":"Mobile",
    "Model": "XUT",
    "Units": 120,
    "Available": "Yes"
}
# Displaying the Dictionary
print(myprod)

# Displaying individual values
print("Product = ",myprod["Product"])
print("Model = ",myprod["Model"])
print("Units = ",myprod["Units"])
print("Available = ",myprod["Available"])

Following is the output of the above program -

{'Product': 'Mobile', 'Model': 'XUT', 'Units': 120, 'Available': 'Yes'}
Product =  Mobile
Model =  XUT
Units =  120
Available =  Yes

Updating values of a Dictionary

We can update the values of a dictionary based on a key by assigning a new value to it, and we also have the update() method, which is used to update one or more key-value pairs. Here is the syntax of updating the values of a dictionary using either the method -

dictionary[key] = new_value
dictionary.update({key: new_value})

Updating a Single Value using the Assignment Operator

We can update a specific value in a Python dictionary by referencing the key and assigning it a new value using the assignment operator "=".

Following is the example, which updates the value of the Product key with Laptop using the assignment operator -

# Creating a Dictionary with 4 key-value pairs
myprod = {
	"Product":"Mobile",
	"Model": "XUT",
	"Units": 120,
	"Available": "Yes"
}

# Displaying the Dictionary
print(myprod)

# Updating Dictionary Values
myprod["Product"] = "Laptop"

# Displaying the Updated Dictionary
print("\nUpdated Dictionary = \n",myprod)
print("Updated Product = ",myprod["Product"])
print("Updated Model = ",myprod["Model"])

Here is the output of the above example -

{'Product': 'Mobile', 'Model': 'XUT', 'Units': 120, 'Available': 'Yes'}

Updated Dictionary =
 {'Product': 'Laptop', 'Model': 'XUT', 'Units': 120, 'Available': 'Yes'}
Updated Product =  Laptop
Updated Model =  XUT

Updating Multiple Values in a Loop

We can update a specific value in a Python dictionary by using the key of the Dictionary and assigning it a new value using the assignment operator "=".

Following is the example, which updates the value of the Product key with Laptop using the assignment operator -

# Creating a Dictionary with 4 key-value pairs
myprod = {
	"Product":"Mobile",
	"Model": "XUT",
	"Units": 120,
	"Available": "Yes"
}

# Displaying the Dictionary
print(myprod)

# Updating Dictionary Values
myprod1 = {"Product": "car", "Model": "SUV", "Available": "No"}
for item in myprod1:
    myprod[item] = myprod1[item]
# Displaying the Updated Dictionary
print("\nUpdated Dictionary = \n",myprod)
print("Updated Product = ",myprod["Product"])
print("Updated Model = ",myprod["Model"])

Below is the output of the above example -

{'Product': 'Mobile', 'Model': 'XUT', 'Units': 120, 'Available': 'Yes'}

Updated Dictionary =
 {'Product': 'car', 'Model': 'SUV', 'Units': 120, 'Available': 'No'}
Updated Product =  car
Updated Model =  SUV

Updating the values using update() method

In this example, we are using the update() method to update the values of keys "Product" and "Model" of the created Dictionary -

# Creating a Dictionary with 4 key-value pairs
myprod = {
	"Product":"Mobile",
	"Model": "XUT",
	"Units": 120,
	"Available": "Yes"
}

# Displaying the Dictionary
print("Dictionary = \n",myprod)
print("Product = ",myprod["Product"])
print("Model = ",myprod["Model"])

# Updating Dictionary Values
myprod.update({"Product":"SmartTV","Model": "PHRG6",})

# Displaying the Updated Dictionary
print("\nUpdated Dictionary = \n",myprod)
print("Updated Product = ",myprod["Product"])
print("Updated Model = ",myprod["Model"])

Here is the output of the above program -

Dictionary =
 {'Product': 'Mobile', 'Model': 'XUT', 'Units': 120, 'Available': 'Yes'}
Product =  Mobile
Model =  XUT

Updated Dictionary =
 {'Product': 'SmartTV', 'Model': 'PHRG6', 'Units': 120, 'Available': 'Yes'}
Updated Product =  SmartTV
Updated Model =  PHRG6

Note: If the key does not exist in the dictionary, then the updating operation will add a new key-value pair to the dictionary.