.. #[Nishanth]: liststart is not a good name. there is no consistency. Use underscores or hyphens instead of spaces and make the filename from LO name Ex: getting_started_with_lists (or) getting_started_lists Hello friends and welcome to the tutorial on getting started with lists. {{{ Show the slide containing title }}} {{{ Show the slide containing the outline slide }}} In this tutorial we will be getting acquainted with a python data structure called lists. We will learn : * How to create lists * Structure of lists * Access list elements * Append elements to lists * Deleting elements from lists .. #[Nishanth]: Did you compile this?? There must an empty before the bulleted list I hope you have ipython running on your system. .. #[Nishanth]: need not specify. Implicit that IPython is running List is a compound data type, it can contain data of other data types. List is also a sequence data type, all the elements are in order and there order has a meaning. We will first create an empty list with no elements. On your IPython shell type :: empty = [] type(empty) This is an empty list without any elements. * Filled lists Lets now define a list, nonempty and fill it with some random elements. nonempty = ['spam', 'eggs', 100, 1.234] Thus the simplest way of creating a list is typing out a sequence of comma-separated values (items) between square brackets. All the list items need not have the same data type. .. #[Nishanth]: do not use "You" or anything else. Stick to "We" As we can see lists can contain different kinds of data. In the previous example 'spam' and 'eggs' are strings and 100 and 1.234 integer and float. Thus we can put elements of heterogenous types in lists. Thus list themselves can be one of the element types possible in lists. Thus lists can also contain other lists. Example :: list_in_list=[[4,2,3,4],'and', 1, 2, 3, 4] We access list elements using the number of index. The index begins from 0. So for list nonempty, nonempty[0] gives the first element, nonempty[1] the second element and so on and nonempty[3] the last element.:: nonempty[0] nonempty[1] nonempty[3] We can also access the elememts from the end using negative indices :: nonempty[-1] nonempty[-2] nonempty[-4] -1 being the last element , -2 second to last and -4 being the first element. .. #[Nishanth]: -1 being last element sounds like -1 is the last element Instead say -1 gives the last element which is 4 .. #[Nishanth]: Instead of saying -4 being the first, say -4 gives 4th from the last which is the first element. * =append= elements We can append elements to the end of a list using append command. :: nonempty.append('onemore') nonempty.append(6) nonempty As we can see non empty appends 'onemore' and 6 at the end. .. #[Nishanth]: First show an example with only one append. may be show the value of a after first append then show what happens after second append Using len function we can check the number of elements in the list nonempty. Because we just appended two elements at the end this returns us 6.:: len(nonempty) .. #[Nishanth]: the "because ..." can be removed. You can simply say len gives the no.of elements which is 6 here Just like we can append elements to a list we can also remove them. There are two ways of doing. One is by using index. :: del(nonempty[1]) .. #[Nishanth]: do not use "You" or anything else. Stick to We deletes the element at index 1, i.e the second element of the list, 'eggs'. The other way is removing element by content. Lets say one wishes to delete 100 from nonempty list the syntax of the command should be :: a.remove(100) but what if their were two 100's. To check that lets do a small experiment. :: a.append('spam') a a.remove('spam') a If we check a now we will see that the first occurence 'spam' is removed thus remove removes the first occurence of the element in the sequence and leaves others untouched. {{{Slide for Summary }}} In this tutorial we came across a sequence data type called lists. :: * We learned how to create lists. * Append elements to list. * Delete Element from list. * And Checking list length. .. #[Nishanth]: See the diff. I have corrected punctuation in many places. The first thing you do before committing is compile the script. I have corrected syntax errors also in many places. {{{ Sponsored by Fossee Slide }}} This tutorial was created as a part of FOSSEE project. I hope you found this tutorial useful. Thank You Author : Amit Sethi First Reviewer : Second Reviewer : Nishanth