I gave a lighting talk at the SF Python meeting tonight about the recommender system I wrote to generate the "Similar Posts" links on this site. The slides are up here.
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Analysis of Shakespeare character speech topics
In Part I of this post I made a topic model of the speech of Shakespeare characters from eight plays. Here in Part II I'll analyze the results of the model. Download notebook.
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Topic modeling of Shakespeare characters
In this post I extract all the words spoken by each character in eight of Shakespeare's plays. Then I construct a topic model to see which characters are generally speaking about similar things. In Part II I look into the information revealed by the topic model. Download notebook.
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Annotating matplotlib plots
To extend on my post about plotting and reshaping data from the BART API, I worked a bit with the matplotlib annotion interface to add text and arrows to a plot. The meat of this post is in cell #4 below. Download notebook.
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Cleaning, reshaping, and plotting BART time series data with pandas
Introduction¶
I recently starting collecting data from the BART API, specifically estimated time to departure for trains at the two stations I use most frequently. In this notebook I'll show how I parsed the data from a csv file, reshaped it to fit the questions at hand, and made a few plots. Download notebook ...read more
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Spark 1.2.0 released
Spark 1.2.0 was released yesterday (release notes). I'm curious to see how the new machine learning API's in spark.ml evolve.
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When joins go wrong, check data types
Writing and debugging joins can be especially difficult when dealing with data from text files. In some cases there is no resulting data, or (much harder to notice!) a few lines that should be included are dropped. Here I'll go into an example of a failed join in pandas, and …
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Installing python for data science
Installing all the python libraries required for data science can be a challenge, especially on windows machine. Unfortunately the same thing that makes the libraries fast also makes them difficult to distribute to different system types. Luckily there are a few free options for getting up and running painlessly. I …
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Using topic modeling to find related blog posts
Over the weekend I got curious about how different posts in this blog were similar to each other, and thought about putting links to similar posts at the end of each article. I used the gensim python library (topic modeling for humans) to find similar articles and I wrote a …
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Scikit-learn machine learning algorithm flowchart
Scikit-learn has a nice flowchart of when to use different machine learning algorithms. View the whole chart here.
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Using sed to make specific text lowercase in place
Data science, I'm sorry to say, often involves cleaning up input data into a usable and uniform format. Command line tools like
...read moregrep,awkandsedprovide an arcane power to manipulate text in files of arbitrary size. Mastering these tools can separate data science novices from data scientists with …There are comments.
Label graph axes!
Download IPython notebook for this post.
It's easy enough to make a plot using matplotlib.
import matplotlib.pyplot as plt import numpy as np time_point_array = np.arange(0, 5, .1) y_value_array = np.exp(time_point_array) plt.plot(time_point_array, y_value_array)
This plot is not great data science. In fact it's poor data …
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Working with dates in pandas: a few examples
pandas has a lot of lifesaving features for dealing with dates. Here's an example timeseries data file, which happens contains a missing date:
date,temp 11-1-2014,56 11-2-2014,56 11-3-2014,59 11-5-2014,60 11-6-2014,55
Loading and plotting the data in pandas gives this result:
...read moreIn [0]: %matplotlib inline In …
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How to quickly test if an element belongs to a group
A common need in data science is to test if a some group of data contains a given value. One specific example would be to test if a word is a stop word.
The slow way
If the elements of the group exist in a
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Filter common words from documents
Often when working with text documents it is useful to filter out words that occur frequently in all documents (e.g. 'the', 'is', ...). These words, called stop words, don't give any special hint about the document's content. The nltk (Natural Language Toolkit) library for python includes a list of stop …
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Get a list of all English words in python
The
nltklibrary for python contains a lot of useful data in addition to it's functions. One convient data set is a list of all english words, accessible like so:from nltk.corpus import words word_list = words.words() # prints 236736 print len(word_list)
You will probably first have to download …
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How to Transition from Ph.D. Student to Data Scientist
A friend of mine recently asked me to share some of my experiences in making the transition from a biophysics Ph.D. student to data scientist. I realized there are probably a lot of people interested in making a similar transition who could benefit from my experience.
Goals
A year …
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Recommended Videos
I put together a list of data science and python videos that I've found to be especaily useful and entertaining. The list is here, also linked from the nav bar up top.
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Recommended Books
I put together a list of data science books I recommended, including a few for preparing for data science interviews. The list is availiable here.
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