Hello friends and welcome to the second tutorial in the series of spoken tutorials on Python for Scientific computing. 

In the previous tutorial we learnt about arrays and we told you that numpy arrays are faster and more efficient . In this tutorial we shall look at creating arrays, accessing elements and changing them. 

Let's start with creating simple arrays. We've already seen how to convert lists to arrays. Inputting a new array is similarto that. 

On your Ipython terminal type a = array open parenthesis and then open square brackets 5,8,10,13 ,close square brackets and close parenthesis . This create an array a . You can see what a is by typing a on the terminal .

Now we will try to create a multi-dimensional array type in your ipython terminal

c= array open parenthesis , then open square brackets 11,12,13 close square bracket 'comma' start square bracket 21 , 22 ,23close square bracket 'comma' open 31,32,33 close square bracket another close square bracket which closes the first sqaure bracket and parenthesis which closes the first parenthesis . Now to see the dimensions of the array c we will do c.shape . We can see that c is a 3 by 3 matrix .

There are other special methods of creating arrays as well we will now look at them .

The first one is the command arange which is similar to range except that it returns an array.

We will type on our Ipython interpreter a = arange(10). We will see what a is now . Type a . As we can see This returns us an array of one dimension and has 10 elements .  

Ones can be use to get all entries as ones . We can pass it the shape of the array as required .

type b=ones open parenthesis , another open parenthesis , 3,4 , close second parenthesis and close first parenthesis . Look at b , by printing it out .

To create an array with all entries as ones, with it's shape similar to an already existing array, we use the ones_like

command.  type b= ones_like in parenthesis a .