Selecting array elements
From time to time, we will want to select a particular element of an array. We will take a look at how to do this, but first, let's create a 2 x 2 matrix again (see the elementselection.py
file in the Chapter02
folder of this book's code bundle):
In: a = array([[1,2],[3,4]]) In: a Out: array([[1, 2], [3, 4]])
The matrix was created this time by passing a list of lists to the array()
function. We will now select each item of the matrix one at a time, as shown in the following code snippet. Remember, the indices are numbered starting from 0.
In: a[0,0] Out: 1 In: a[0,1] Out: 2 In: a[1,0] Out: 3 In: a[1,1] Out: 4
As you can see, selecting elements of the array is pretty simple. For the array a
, we just use the notation a[m,n]
, where m
and n
are the indices of the item in the array.