Unlocking the Power of Diagonal Arrays
When working with arrays, having the right tools at your disposal can make all the difference. One such tool is the diag() method, which allows you to create or extract diagonal elements from arrays. But what exactly does it do, and how can you harness its power?
Creating Diagonal Arrays
The diag() method can take a 1D array as input and create a new array with those elements as its diagonal. But that’s not all – you can also control the placement of the diagonal elements using the optional k argument. By default, k is set to 0, which represents the main diagonal. However, you can set k to a positive integer to create diagonals above the main diagonal, or a negative integer to create diagonals below it.
Example 1: Creating a Diagonal Array
Let’s see this in action. When we pass a 1D array to diag(), it creates a diagonal array with the given array as its diagonal elements. For instance:
Output
As you can see, the resulting array has the input elements as its diagonal.
Extracting Diagonals from 2D Arrays
But what if you have a 2D array and want to extract its diagonal elements? That’s where diag() comes in handy again. When you pass a 2D array to diag(), it returns a 1D array containing the diagonal elements of the original array.
Example 2: Extracting Diagonals
Let’s take a look at an example:
Output
As you can see, the resulting array contains the diagonal elements of the original 2D array.
Related Methods: diagflat()
Did you know that there’s a related method called diagflat()? This method creates a 2D array with the flattened input as its diagonal. The key difference is that diagflat() automatically flattens the input array, whereas diag() requires manual flattening using the flatten() method.
Output
As you can see, diagflat() produces a similar result to diag(), but with the added convenience of automatic flattening.
By mastering the diag() method and its related cousins, you’ll be able to unlock new possibilities in your array manipulation workflows. So go ahead, give it a try, and see what kind of diagonal magic you can create!