# Data Structures and Algorithms with Object-Oriented Design Patterns in Python

Twitter sentiment analysis using Python and NLTK | Laurent Luce's Blog This post describes the implementation of sentiment analysis of tweets using Python and the natural language toolkit NLTK. The post also describes the internals of NLTK related to this implementation. Background The purpose of the implementation is to be able to automatically classify a tweet as a positive or negative tweet sentiment wise. The classifier needs to be trained and to do that, we need a list of manually classified tweets. Let’s start with 5 positive tweets and 5 negative tweets. Positive tweets: I love this car.This view is amazing.I feel great this morning.I am so excited about the concert.He is my best friend. Negative tweets: I do not like this car.This view is horrible.I feel tired this morning.I am not looking forward to the concert.He is my enemy. In the full implementation, I use about 600 positive tweets and 600 negative tweets to train the classifier. Next is a test set so we can assess the exactitude of the trained classifier. Test tweets: Implementation Classifier Classify

Learn Python - Free Interactive Python Tutorial The Python “with” Statement by Example Python’s with statement was first introduced five years ago, in Python 2.5. It’s handy when you have two related operations which you’d like to execute as a pair, with a block of code in between. The classic example is opening a file, manipulating the file, then closing it: with open('output.txt', 'w') as f: f.write('Hi there!') The above with statement will automatically close the file after the nested block of code. Here’s another example. This code sample uses a Context object (“cairo context”) to draw six rectangles, each with a different rotation. cr.translate(68, 68) for i in xrange(6): cr.save() cr.rotate(2 * math.pi * i / 6) cr.rectangle(-25, -60, 50, 40) cr.stroke() cr.restore() That’s a fairly simple example, but for larger scripts, it can become cumbersome to keep track of which save goes with which restore, and to keep them correctly matched. By themselves, pycairo’s save and restore methods do not support the with statement, so we’ll have to add the support on our own.