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Python logging to stackdriver

I recently deployed a python application in google app engine / container engine. When I went to check the logs, everything was logged at the “ERROR” level even though my application uses python logging properly. As far as I know there are 2 ways to fix that:

  1. Use the stackdriver client, which requires an additional dependency and somewhat binds your program to google app engine.
  2. Format the logs in a way that stackdriver can parse them, which is easily configurable.

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Lecture: Machine Learning in Action

Après un peu plus de 3 années passées chez Datacratic, il était grand temps que je m’intéresse davantage à l’apprentissage machine. C’est le livre Machine Learning in Action que j’ai choisi pour me lancer.

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Machine Learning in Action Book Cover Machine Learning in Action
Peter Harrington
Computers
Manning Publications
2011-12
354

Provides information on the concepts of machine theory, covering such topics as statistical data processing, data visualization, and forecasting.

Query string white space vs plus

Trivia: What is the difference between the encoded query string parameter “a+b” and “a%20b” ?

Answer: Nothing! They are both encoded representations for “a b”.

Isn’t a “+” supposed to remain a “+”? Well, the URL and the query strings are not encoded following the same rules. In the URL, the “+” remains a “+” indeed, but in the query string it’s actually encoded and becomes a “%2B”. This can be misleading.
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Python: warnings and deprecation

Aside the logging library resides the less known warning library. The former is meant to log events related to execution whereas the later is meant to warn more or less about improper module usage or deprecated functions. By default, most warnings are displayed once, meaning that they will not clutter your logs by being shown repeatedly. However, some are “ignored by default”, hence not displayed at all. This is where the important difference with logging is: the control you get over them at the command line level.

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Python counters on unhashable types

Have you ever heard or used python counters? They are very useful to count the number of occurrences of “simple” items. Basically:

> from collections import Counter
> colors = ['red', 'blue', 'red', 'green']
> Counter(colors)
Counter({'red': 2, 'blue': 1, 'green': 1})

However, if you try to use it on non hashable types it doesn’t work.

> colors = [['red', 'warm'], ['blue', 'cold'], ['red', 'warm']]
> Counter(colors)
[...]
TypeError: unhashable type: 'list'

What do we do then?

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Lecture: Python Cookbook

Le nom de ce livre ne pourrait être mieux choisi. On traite à 99% de python (il y a un peu de C) et l’approche utilisée est effectivement celle d’un livre de recettes. Chaque section se découpe en trois parties: un problème, une solution et des notes à propos de la solution.

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Python Cookbook Book Cover Python Cookbook
David Beazley, Brian Jones,
Computers
O'Reilly Media, Incorporated
2013-05-15
600