Python – Check for None value in Matrix

• Last Updated : 30 Dec, 2020

Python supports a list as its list element and hence a matrix can be formed. Sometimes we might have a utility in which we require to perform None check in that list of list i.e matrix and its a very common in all the domains of coding especially Data Science. Letâ€™s discuss certain ways in which this can be performed.

Method #1 : Using `any()` + list comprehension
The any function can be used to perform the task of if condition and the check for each element in the nested list can be computed using the list comprehension.

 `6``# Python3 code to demonstrate``# Search in Matrix``# using any() + list comprehension`` ` `# initializing list``test_list ``=` `[[``4``, ``5``, ``6``],``            ``[``10``, ``2``, ``None``],``            ``[``1``, ``11``, ``18``]]`` ` `# printing original list ``print``(``"The original list : "` `+` `str``(test_list))`` ` `# using any() + list comprehension``# to Search in Matrix``res ``=` `any``(``None` `in` `sub ``for` `sub ``in` `test_list)`` ` `# printing result``print``(``"Does Matrix contain None value ? : "` `+` `str``(res))`
Output :
```The original list : [[4, 5, 6], [10, 2, None], [1, 11, 18]]
Does Matrix contain None value ? : True
```

Method #2 : Using` set.issubset() + itertools.chain()`
The issubset method can be used to check for the membership in sublist and chain function can be used to perform this task for the each element in the Matrix, in a faster way as it works on iterators.

 `# Python3 code to demonstrate``# Check for None value in Matrix``# using set.issubset() + itertools.chain()``from` `itertools ``import` `chain`` ` `# initializing list``test_list ``=` `[[``4``, ``5``, ``6``],``            ``[``10``, ``2``, ``None``],``            ``[``1``, ``11``, ``18``]]`` ` `# printing original list ``print``(``"The original list : "` `+` `str``(test_list))`` ` `# using set.issubset() + itertools.chain()``# to Search in Matrix``res ``=` `{``None``}.issubset(chain.from_iterable(test_list))`` ` `# printing result``print``(``"Does Matrix contain None value ? : "` `+` `str``(res))`
Output :
```The original list : [[4, 5, 6], [10, 2, None], [1, 11, 18]]
Does Matrix contain None value ? : True
```

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