Name: [002] Ian Ozsvald
Member: 90 months
Authored: 181 videos
Description: I am the co-founder of ShowMeDo (see http://showmedo.com/about), author of `The Screencasting Handbook <http://thescreencastinghandbook.com>`_ and the founder of the professional screencast production company `ProCasts <http://procasts.co.uk>`_: .. image:: http://procasts.co.uk/media/procasts_sma ...

Python Beginners - Loops and Iteration [ID:296]

a series of video-tutorials by Ian Ozsvald

Go to a video in this series:

Iterating over a block of code is a very common operation when programming. Here I show you the 'for' and 'while' commands in Python, they let you iterate over a sequence of items and repeat blocks of code under a truth condition.

I'll show you how to use the 'for' loop on a list, set and dictionary whilst using iteration, range and enumerate. For the 'while' loop I'll show you an example of getting user-input (with 'raw_input') to build up a list of answers.

At the end of the series you'll have a firm knowledge for using 'for' and 'while' with Python.

Video Tutorials

1. Overview (Loops and Iteration)

by Ian Ozsvald added 07/08

In this 2 minute introduction I'll show you two code examples of the 'for' and 'while' loop. As mentioned, in this series we use 'range', 'len', 'enumerate' on 'list', 'set', 'dict' along with 'raw_input'. After watching this series you'll have a firm knowledge of how to iterate with two powerful Python commands.

32 votes

2. For on a List

by Ian Ozsvald added 07/08

The 'for' command lets us iterate over a sequence of items, commonly we use it to iterate over the items in a list. This is exactly the use-case I show you here. We'll also look at using 'break' and 'continue', along with the less-usual 'else' statement (normally you only see 'else' on 'if' statements). Note that there is an AUDIO TYPO in this episode - I mention 'comment out' when I should be s [...]

35 votes

3. For using a range

by Ian Ozsvald added 07/08

Older languages let you use a for loop simply to create a list of index values, you'd then use these to index into a container. In Python we can replicate this behaviour with 'len' and 'range'. This builds up to the 'enumerate' example in the next episode. Both techniques are useful as sometimes we want to have both the index of the item and the item itself (without having to type too much!). S [...]

17 votes

4. For using enumerate

by Ian Ozsvald added 07/08

The 'enumerate' function builds on the last episode - we can get the index of an item and the item itself in a simple statement. 'enumerate' was added in Python 2.3. Links: built-in functions Looping Techniques

24 votes

5. For on a set

by Ian Ozsvald added 09/08

Sets store a unique collection of values (unlike a list which can store repeated references to the same value). Sets are different to lists in that you can't index into them - I show you what happens when you try. You can however use the 'for' loop to iterate over the items in a set. See also Set Types -- set, frozenset.

19 votes

6. For on a dict(ionary)

by Ian Ozsvald added 09/08

Dictionaries let us store values which we address using a key. We can use a 'for' loop to extract both the keys, values and key+value pairs, I show you how in this episode. Links: Dictionaries dict mapping

15 votes

7. While loops

by Ian Ozsvald added 09/08

The 'while' loop is different to the 'for' loop. Rather than iterating over a sequnce of items, instead we repeatedly run a block of code under the control of a logical test. The 'while' look can be controlled using the 'break', 'continue' and 'else' statements just like the 'for' loop. Here we use a simple example of the 'while' loop to build a list of user-input (obtained using 'raw_input'). [...]

29 votes

Educating the Open-source Community With Showmedo

Although as important as the software it supports, education and documentation are relatively neglected in the Open-source world. Coders love to code, and explaining how best to use or improve the software tends to be deferred or even sidelined.

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Screencasting is easier than you think, and we're happy to help you. You can emailus for advice or just use some of the how-to screencasts on the site. This screencasting learning-pathis a good place to start.

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The focus at the moment is on developing with the Python programming language, one of the backbones of the FOSS movement with a huge number of included and third-party libraries.

Python Beginners - Loops and Iteration [ID:296]

a series of video-tutorials by Ian Ozsvald

Video Tutorials

1. Overview (Loops and Iteration)

2. For on a List

3. For using a range

4. For using enumerate

5. For on a set

6. For on a dict(ionary)

7. While loops

Educating the Open-source Community With Showmedo

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