Fetching Entries in Dictionary Based on Condition in Python

In Python, dictionaries provide a flexible way to store key-value pairs. Fetching entries in a dictionary based on a specific condition is a common task. This can be achieved using various methods, each with its advantages and use cases. In this article, we will explore different methods to fetch entries in a dictionary based on a condition.

Fetching Entries in a Dictionary Based on a Condition in Python

Below are some of the ways by which we can fetch entries in a dictionary based on a condition in Python:

• Using Dictionary Comprehension
• Using Filter() Function
• Using Items() Method with Loop

Fetching Entries in a Dictionary Using Dictionary Comprehension

In this example, we use dictionary comprehension to create a new dictionary (filtered_dict) that contains only the entries with scores greater than or equal to 75. The condition (if value >= 75) filters out entries that do not meet the criteria.

Python3

# initializing dictionary
original_dict = {'Alice': 85, 'Bob': 72, 'Charlie': 90, 'David': 68}

filtered_dict = {key: value for key,
                 value in original_dict.items() if value >= 75}

# Displaying the result
print("Dictionary Comprehension:", filtered_dict)

Output

Dictionary Comprehension: {'Alice': 85, 'Charlie': 90}

Filtering Entries in a Dictionary Using Filter() Function

In this method, a custom filtering function (filter_scores) is defined, which returns True if the value is greater than or equal to 75. The filter() function is then applied to the items of the original dictionary, and the result is converted back to a dictionary using dict().

Python3

original_dict = {'Alice': 85, 'Bob': 72, 'Charlie': 90, 'David': 68}

# Define a filtering function
def filter_scores(item):
    return item[1] >= 75

filtered_dict = dict(filter(filter_scores, original_dict.items()))

# Displaying the result
print("Filter() Function:", filtered_dict)

Output

Filter() Function: {'Alice': 85, 'Charlie': 90}

Filtering Entries in a Dictionary Using Items() Method

In this method, we iterate through the items of the original dictionary using a loop (for key, value in original_dict.items()). Entries meeting the condition (if value >= 75) are added to a new dictionary (filtered_dict).

Python3

# initializing dictionary
original_dict = {'Alice': 85, 'Bob': 72, 'Charlie': 90, 'David': 68}

filtered_dict = {}
for key, value in original_dict.items():
    if value >= 75:
        filtered_dict[key] = value

# Displaying the result
print("Items() Method with Loop:", filtered_dict)

Output

Items() Method with Loop: {'Alice': 85, 'Charlie': 90}