Related Articles

# Python – Flag None Element Rows in Matrix

• Last Updated : 02 Sep, 2020

Given a Matrix, return True for rows which contain a None Value, else return False.

Input : test_list = [[2, 4, None, 3], [3, 4, 1, None], [2, 4, 7, 4], [2, 8, None]]
Output : [True, True, False, True]
Explanation : 1, 2 and 4th index contain None occurrence.

Input : test_list = [[2, 4, None, 3], [3, 4, 1, None], [2, 4, None, 4], [2, 8, None]]
Output : [True, True, True, True]
Explanation : All rows have None.

Method #1 : Using List comprehension

In this, we iterate for each row and use in operator to check for None in these. If found, True is returned, else False is returned.

## Python3

 `# Python3 code to demonstrate working of ``# Flag None Element Rows in Matrix``# Using list comprehension`` ` `# initializing list``test_list ``=` `[[``2``, ``4``, ``None``, ``3``], [``3``, ``4``, ``1``, ``None``], [``2``, ``4``, ``7``, ``4``], [``2``, ``8``]]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# in operator to check None value ``# True if any None is found ``res ``=` `[``True` `if` `None` `in` `sub ``else` `False` `for` `sub ``in` `test_list]`` ` `# printing result ``print``(``"None Flagged List : "` `+` `str``(res))`
Output
```The original list is : [[2, 4, None, 3], [3, 4, 1, None], [2, 4, 7, 4], [2, 8]]
None Flagged List : [True, True, False, False]
```

Method #2 : Using all() + list comprehension

In this, we check for all values to be True using all(), if yes, its not flagged True and list comprehension is used to check for each row.

## Python3

 `# Python3 code to demonstrate working of ``# Flag None Element Rows in Matrix``# Using all() + list comprehension`` ` `# initializing list``test_list ``=` `[[``2``, ``4``, ``None``, ``3``], [``3``, ``4``, ``1``, ``None``], [``2``, ``4``, ``7``, ``4``], [``2``, ``8``]]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# all() checks for all non none values  ``res ``=` `[``False` `if` `all``(sub) ``else` `True` `for` `sub ``in` `test_list]`` ` `# printing result ``print``(``"None Flagged List : "` `+` `str``(res))`
Output
```The original list is : [[2, 4, None, 3], [3, 4, 1, None], [2, 4, 7, 4], [2, 8]]
None Flagged List : [True, True, False, False]
```

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up