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Python: Casts the provided value as a list if it's not one

Python List: Exercise - 266 with Solution

Write a Python program to cast the provided value as a list if it's not one.

  • Use isinstance() to check if the given value is enumerable.
  • Return it by using list() or encapsulated in a list accordingly.

Sample Solution:

Python Code:

def cast_list(val):
  return list(val) if isinstance(val, (tuple, list, set, dict)) else [val]
d1 = [1]
print(type(d1))
print(cast_list(d1)) 
d2 = ('Red', 'Green')
print(type(d2))
print(cast_list(d2)) 
d3 = {'Red', 'Green'}
print(type(d3))
print(cast_list(d3))
d4 = {1: 'Red', 2: 'Green', 3: 'Black'}
print(type(d4))
print(cast_list(d4))

Sample Output:

<class 'list'>
[1]
<class 'tuple'>
['Red', 'Green']
<class 'set'>
['Green', 'Red']
<class 'dict'>
[1, 2, 3]

Flowchart:

Flowchart: Casts the provided value as a list if it's not one.

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Previous: Write a Python program to generate a list, containing the Fibonacci sequence, up until the nth term.
Next: Write a Python program to get the cumulative sum of the elements of a given list.

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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