I've started working on the revised 2nd Edition of Python for Data Analysis. The agenda / table of contents is not set in stone, though!

Any comments on the existing content or requests for new content would be welcome here. I can't make any promises, but since I know how useful the book has been for many people the last 3.5 years, I would like to make sure the 2nd edition is just as useful (if not more so!) in the following 3.5 years (which will put us all the way to 2020, if you can believe it).

Thank you all in advance for the support.

Still having trouble using JSON in Python 3

I have added the 'rb' to open() records = [json.loads(line) for line in open(path,'rb')]

Now getting error in json.loads

TypeError: the JSON object must be str, not 'bytes'

Any help appreciated Thanks

I'm new to your book and trying like crazy---but I seem to be missing a lot somewhere, somehow. I hope you can help me. I have tried to work through the usa.gov data from bit.ly and I always get no such file exists errors. The same goes for the movielens data...no matter how I try I get the same errors. Am I supposed to download those files separately? I've culled the net looking for better code but I figured you could point me in the right direction or tell me what I'm doing wrong?

Please help. I would hate for this book to have been a terrible waste!!!

This is in the ch05.ipynb

Changed pd.DataFrame(pop, index=[2001, 2002, 2003]) to pd.DataFrame(pop, index=pd.Series([2001, 2002, 2003])) in order to get this cell to compile

Vectorized String Functions in pandas

I can't figure out the meaning of the following code, can you explain it further:

In [176]: matches .str.get(1) Out[176]: Dave NaN Rob NaN Steve NaN Wes NaN dtype: float64

In [177]: matches .str[0] Out[177]: Dave NaN Rob NaN Steve NaN Wes NaN dtype: float64

I have downloaded all the files in this repository. When I try to work with them, for example using the code list(open(('examples/ex3.txt'), I consistently receive the following error:

FileNotFoundError: [Errno 2] No such file or directory: 'ex3.txt'

Do you know of any potential causes for this issue? Does it have to do with the directory that I have saved my download to?

Hi,

I am working through the Ch02 material - and have a problem with the initial reading of the movie lens data. I am running the initial code as in the book:

import pandas as pd
import os
encoding = 'latin1'


upath = os.path.expanduser('pydata-book-master/ch02/movielens/users.dat')
rpath = os.path.expanduser('pydata-book-master/ch02/movielens/ratings.dat')
mpath = os.path.expanduser('pydata-book-master/ch02/movielens/movies.dat')

unames = ['user_id', 'gender', 'age', 'occupation', 'zip']
rnames = ['user_id', 'movie_id', 'rating', 'timestamp']
mnames = ['movie_id', 'title', 'genres']

(with paths amended to work for where I have the files)

but when I run the line:

users = pd.read_csv(upath, sep='::', header=None, names=unames, encoding=encoding)

I get the message:

/Users/Chris/anaconda3/lib/python3.6/site-packages/ipykernel/__main__.py:1: ParserWarning: Falling back to the 'python' engine because the 'c' engine does not support regex separators (separators > 1 char and different from '\s+' are interpreted as regex); you can avoid this warning by specifying engine='python'.
  if __name__ == '__main__':

I have tried switching to a Python2 kernel - but get an equivalent message.

What is the root of this issue? as far as I can interpret this it is having a problem with specifying the multicharacter '::' as the data separator. But I don't really understand how to correct this. How should I fix it to avoid similar issues with this and future code in the book?

Many thanks

The 2 code examples are the same.

In[216]: ts.resample('5min', closed='right').sum()

In[217]: ts.resample('5min', closed='right').sum()

216 should be without the closed='right'

Hi Guys,

I'm facing some error when running on "Prop_cumsum". I posted on stackoverflow but can't seem to find a solution there.

I did everything correct prior to running this error, including;

• changing Row to Indexs and Cols to Columns from the previous commands.

The error message is on this link below

http://stackoverflow.com/questions/41298599/python-for-data-analysis-chp-2-pg-38-prop-cumsum-error?noredirect=1#comment69866535_41298599

Thanks guys

Hi,

Something is wrong with record 495 from ch02/usagov_bitly_data2012-03-16-1331923249.txt.

It causes error when running these statements:

import json
path = 'ch02/usagov_bitly_data2012-03-16-1331923249.txt'
records = [json.loads(line) for line in open(path)]

Fixed version:

import json
path ='ch02/usagov_bitly_data2012-03-16-1331923249.txt'
temp = [line for line in open(path)]
temp.pop(495)          # delete problematic record
for i in range(len(temp)):
     records[i] = json.loads(temp[i])

Chapter 5, Paragraph 2, at this link: https://wesmckinney.com/book/pandas-basics.html

While pandas adopts many coding idioms from NumPy, the biggestabout difference is that pandas is designed for working with tabular or heterogeneous data.

The word biggestabout seems to be a typo, where it should just be biggest?

Since MSFT is a valid Python variable name, we can also select these columns using more concise syntax: In [285]: returns["MSFT"].corr(returns["IBM"])

should be as in 2nd Edition: returns.MSFT.corr(returns.IBM)

Otherwise there is no difference between the [283] code and the [285] code. Thanks.

The first two lines are Python code statements; the second statement creates a variable named data that refers to a newly created Python dictionary. The last line prints the value of data in the console.

CORRECTION: data is a list not dictionary

In [5]: import numpy as np

In [6]: data = [np.random.standard_normal() for i in range(7)]

In [7]: data