Array Constraints

Arrays are fixed-sized. After creating an array with n elements, the size of the array will be n and it cannot be changed later. To have a bigger or smaller array we need to create a new one and populate it with data. Arrays don't support append nor delete like Python lists do.

For example:

ary = np.array([34, 59, 5])

The ary variable holds a 1-dimensional array that contains 3 elements.

To access each element we use [] brackets just like a regular Python list:

ary[1] # holds the value 59

To delete an element use np.delete. it won't affect the original ary, but rather it will return a new array without the element it is deleting.
To replace the new smaller array with the original ary assign the result to the ary variable:

ary = np.delete(ary, 1)

To add an element use np.append

ary = np.append(ary, 5)

Now the ary will hold [34, 59, 5, 5]. np.append also returns a new array and does not modify the original array.

To access the last element we can use multiple options:

ary[-1]
ary[len(ary)-1]
ary[2]

Just like with a normal Python list