Python: Extract a list of values from a given list of dictionaries

Last update on June 28 2025 12:41:07 (UTC/GMT +8 hours)

52. Extract List of Values from List of Dictionaries

Write a Python program to extract a list of values from a given list of dictionaries.

Visual Presentation:

Sample Solution:

Python Code:

# Define a function 'test' that extracts a list of values for a specific subject ('marks') from a list of dictionaries ('lst').
def test(lst, marks):
    # Use a list comprehension to extract the values associated with the subject ('marks') in each dictionary.
    result = [d[marks] for d in lst if marks in d]
    return result

# Create a list of dictionaries 'marks' with subjects 'Math' and 'Science' and associated marks.
marks = [{'Math': 90, 'Science': 92}, 
         {'Math': 89, 'Science': 94}, 
         {'Math': 92, 'Science': 88}]

# Print a message indicating the start of the code section and the original list of dictionaries.
print("\nOriginal Dictionary:")
print(marks)

# Define the subject 'subj' as "Science".
subj = "Science"

# Print a message indicating the intention to extract values for the subject 'subj' from the list of dictionaries.
print("\nExtract a list of values from the said list of dictionaries where subject =", subj)

# Call the 'test' function to extract the values associated with the subject 'subj' and print the result.
print(test(marks, subj))

# Print a message indicating the start of the code section and the original list of dictionaries.
print("\nOriginal Dictionary:")
print(marks)

# Define the subject 'subj' as "Math".
subj = "Math"

# Print a message indicating the intention to extract values for the subject 'subj' from the list of dictionaries.
print("\nExtract a list of values from the said list of dictionaries where subject =", subj)

# Call the 'test' function to extract the values associated with the subject 'subj' and print the result.
print(test(marks, subj)) 

Sample Output:

Original Dictionary:
[{'Math': 90, 'Science': 92}, {'Math': 89, 'Science': 94}, {'Math': 92, 'Science': 88}]

Extract a list of values from said list of dictionaries where subject = Science
[92, 94, 88]

Original Dictionary:
[{'Math': 90, 'Science': 92}, {'Math': 89, 'Science': 94}, {'Math': 92, 'Science': 88}]

Extract a list of values from said list of dictionaries where subject = Math
[90, 89, 92]

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to extract the values for a specified key from a list of dictionaries using list comprehension.
• Write a Python program to iterate through a list of dictionaries and collect values corresponding to a given key, handling missing keys.
• Write a Python program to use the map() function to retrieve values for a specified key from each dictionary in a list.
• Write a Python function that returns a list of values for a given key from a list of dictionaries, excluding dictionaries where the key is absent.

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