Boolean mask arrays

- [Instructor] When you open the Boolean Mask Arrays file…in the exercises folder you'll see that it is pre-populated…with a numpy import statement,…and with a variable called my vector,…which is populated with a python list.…Before you begin using this interactive notebook,…you want to execute both of theses cells.…You can execute them both separately,…or you can go to the cell menu and select run all.…After you've selected run all you'll see that the values…in my vector are now in ND array,…and the values of the elements are exactly the same…as the values in the python list.…

Now I'm going to cut and paste the next cell…from the exercises file.…In it, I'm creating a new variable called…zero mod seven mask.…It takes on the values where my vector…is exactly divisible by seven.…In particular, the percentage sign is the remainder operator…and we're selecting all elements in the array…where the remainder after division…by seven is equal to zero.…I'm pressing shift + enter.…

We see that we've created an array of Boolean values.…