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Includes code I wrote for specific assignments

  • General Assignments; larger projects will be in another repo. These are from courses:
    • Coursera Python Data Analysis
    • Coursera Data Science Maths
    • Coursera Python Data Representations
    • Udacity's Data Analyst Nanodegree
    • DataCamp 'Intro to SQL' course

Set Up

  • Local is set up as standard
  • Cloud9 set up
## to start up notebook
ipython notebook --ip=0.0.0.0 --port=8080 --no-browser
## use token to validate
## this is in the cloud publicly, so be careful what is in here
## to see notebook->https://instancename(topfolder)-username.c9users.io

Types of Data

  • XML
  • JSON
  • CSVs
  • WebScraped data

Regularly Used Functions

  • import libraries
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline
  • read in data
df = pd.read_csv('data.csv')
  • rename unnamed column
df = df.loc[:, ~df.columns.str.contains('^Unnamed')]

Notes

  • Binomial Distribution
n!
-----
k!(n-k)!

Normalization

  • Normal distribution with mean and variance
Area under curve

  1
----
(2 * pi * (sigma^2))^(1/2)

SQL stuff

  • unique values
SELECT DISTINCT x
FROM y;
  • count distinct
SELECT COUNT(DISTINCT x)
FROM y;
  • CAUSE (IF THEN)
  • COALESCE
  • EXPLAIN (helps with showing order of operation for data processing)

Jupyter stuff

  • draw a random number (n) of samples from data
randomnum = np.random.choice(data, n)
  • calculate the mean of that sample
randomnum.mean()
  • calculate the variance
np.var(randomnum)
  • calculate standard deviation
np.std(randomnum)
  • for looping through and appending sample data in array
arr = []
# get a sample of 20 random draw from data
for i in range(100000): 
    # 10000 generated values, append
    sample = np.random.choice(data, 20)
    #  append the mean for each sample mean
    arr.append(sample.mean())

Visualization using Matplotlib

import matplotlib.pyplot as plt
%matplotlib inline

# plot histogram of arr
plt.hist(arr);

Concepts

Bootsrapping

  • Bootstrapping is sampling with replacement

Hypothesis Testing

Confidence Intervals

Bonferroni Correction

P-values

Libraries

  • import xml.etree.ElementTree
  • prettyprint
  • xlrd
  • pandas
  • numpy
  • Beautiful Soup

DataGraphs

data and graphs

  • Statistics
  • Python
  • Graphs, etc

Skills

  • SQL
  • R (ggplot, etc)
  • Python (pandas, numpy, scipy, etc)
  • Mongo DB

Concepts

  • Simpson's Paradox

Notes from

  • Data Science Maths
  • Bayesian Statistics