# Python | Matrix True Summation

Checking a number/element by a condition is a common problem one faces and is done in almost every program. Sometimes we also require to get the totals that match the particular condition to have a distinguish which to not match for further utilization like in data Science. Lets discuss certain ways in which we can count True values in Matrix.

Method #1 : Using `sum()` + generator expression
This method uses the trick of adding 1 to the sum whenever the generator expression returns true. By the time list gets exhausted, summation of count of numbers matching a condition is returned.

 `# Python 3 code to demonstrate  ` `# Matrix True Summation ` `# using sum() + generator expression  ` `from` `itertools ``import` `chain ` ` `  `# initializing list  ` `test_list ``=` `[[``3``, ``False``], [``False``, ``6``], [``False``, ``9``]]  ` ` `  `# printing original list  ` `print` `(``"The original list is : "` `+` `str``(test_list))  ` ` `  `# using sum() + generator expression  ` `# Matrix True Summation ` `res ``=` `sum``(``1` `for` `i ``in` `chain.from_iterable(test_list) ``if` `i ``=``=` `True``)  ` ` `  `# printing result  ` `print` `(``"The number of True elements: "` `+` `str``(res))  `

Output :

```The original list is : [[3, True], [True, 6], [True, 9]]
The number of True elements: 3
```

Method #2 : Using `sum() + map()`
map() does the task almost similar to the generator expression, difference is just the internal data structure employed by it is different hence more efficient.

 `# Python 3 code to demonstrate  ` `# Matrix True Summation ` `# using sum()+ map()  ` `from` `itertools ``import` `chain ` ` `  `# initializing list  ` `test_list ``=` `[[``3``, ``True``], [``True``, ``6``], [``True``, ``9``]]  ` ` `  `# printing original list  ` `print` `(``"The original list is : "` `+` `str``(test_list))  ` ` `  `# using sum()+ map()  ` `# Matrix True Summation ` `res ``=` `sum``(``map``(``lambda` `i: i ``=``=` `True``, chain.from_iterable(test_list)))  ` ` `  `# printing result  ` `print` `(``"The number of True elements: "` `+` `str``(res))  `

Output :

```The original list is : [[3, True], [True, 6], [True, 9]]
The number of True elements: 3
```

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.

My Personal Notes arrow_drop_up Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.