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

Python dictionary: Exercise-52 with Solution

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

Sample Solution:

Python Code:

def test(lst, marks):
    result = [d[marks] for d in lst if marks in d]
 
    return result

marks = [{'Math': 90, 'Science': 92}, 
         {'Math': 89, 'Science': 94}, 
         {'Math': 92, 'Science': 88}]

print("\nOriginal Dictionary:")
print(marks)
subj = "Science"
print("\nExtract a list of values from said list of dictionaries where subject =",subj)
print(test(marks, subj))

print("\nOriginal Dictionary:")
print(marks)
subj = "Math"
print("\nExtract a list of values from said list of dictionaries where subject =",subj)
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]

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

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Flowchart: Extract a list of values from a given list of dictionaries.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m