Fix Python – What’s a correct and good way to implement __hash__()?

What’s a correct and good way to implement __hash__()?
I am talking about the function that returns a hashcode that is then used to insert objects into hashtables aka dictionaries.
As __hash__() returns an integer and is used for “binning” objects into hashtables I assume that the values of the returned integer should be uniformly distributed for ….

Fix Python – Object of custom type as dictionary key

What must I do to use my objects of a custom type as keys in a Python dictionary (where I don’t want the “object id” to act as the key) , e.g.
class MyThing:
def __init__(self,name,location,length):
self.name = name
self.location = location
self.length = length

I’d want to use MyThing’s as keys that are co….

Fix Python – SQLAlchemy: engine, connection and session difference

I use SQLAlchemy and there are at least three entities: engine, session and connection, which have execute method, so if I e.g. want to select all records from table I can do this
engine.execute(select([table])).fetchall()

and this
connection.execute(select([table])).fetchall()

and even this
session.execute(select([table])).fetchall()

– the res….

Fix Python – Generate a heatmap using a scatter data set

I have a set of X,Y data points (about 10k) that are easy to plot as a scatter plot but that I would like to represent as a heatmap.
I looked through the examples in Matplotlib and they all seem to already start with heatmap cell values to generate the image.
Is there a method that converts a bunch of x, y, all different, to a heatmap (where zones….

Fix Python – Removing a list of characters in string

I want to remove characters in a string in python:
string.replace(‘,’, ”).replace(“!”, ”).replace(“:”, ”).replace(“;”, ”)…

But I have many characters I have to remove. I thought about a list
list = [‘,’, ‘!’, ‘.’, ‘;’…]

But how can I use the list to replace the characters in the string?
….

Fix Python – Can’t pickle when using multiprocessing Pool.map()

I’m trying to use multiprocessing’s Pool.map() function to divide out work simultaneously. When I use the following code, it works fine:
import multiprocessing

def f(x):
return x*x

def go():
pool = multiprocessing.Pool(processes=4)
print pool.map(f, range(10))

if __name__== ‘__main__’ :
go()

However, when I use it in a….