Thought I'd give a big hi today in apologies for the lack of length that this blog post has in comparison with my somewhat hectic previous one. I can't consistently keep banging out blog posts that long though, I'm pretty busy.
So… List Comprehensions
Moving right along I have learnt how to use a fantastic paradigm in python for creating lists based on other lists called list comprehensions.
Take the following:
# A list of numbers old_list = [1,2,3,4,5,6,7,8,9,10] # Create a new list new_list =  # Iterate through previous list and add only the even numbers to the new list. for number in old_list: if number % 2 == 0: new_list.append(number)
Cool! So obviously what we are trying to do here is extract the even numbers from the old list.
So lets try that out using list comprehensions:
# A list of numbers old_list = [1,2,3,4,5,6,7,8,9,10] new_list = [number for number in old_list if number % 2 == 0]
Would you look at that? The new list creation is now a one liner!
Awesome, so how does it work?
Glad you asked. So, as the name suggests, python is capable of 'comprehending' lists in a simplified way that makes reading a breeze (once you get used to it). A basic format might be something like:
list = [ITEM FROM ORIGINAL LIST for ITEM FROM ORIGINAL LIST in ORIGINAL LIST]
Alternatively, you could swing in the opposite direction and just go to town on the conditions and chain if statements like so:
new_list = [number for number in old_list if number > 1 if number < 3] result: 
That's all for this week!
Like I said, short and sweet today. Tune in next week for some more geek talk!