Nikita Zavgorodnii nikitajz

10 Scala One Liners to Impress Your Friends

Here are 10 one-liners which show the power of scala programming, impress your friends and woo women; ok, maybe not. However, these one liners are a good set of examples using functional programming and scala syntax you may not be familiar with. I feel there is no better way to learn than to see real examples.

Updated: June 17, 2011 - I'm amazed at the popularity of this post, glad everyone enjoyed it and to see it duplicated across so many languages. I've included some of the suggestions to shorten up some of my scala examples. Some I intentionally left longer as a way for explaining / understanding what the functions were doing, not necessarily to produce the shortest possible code; so I'll include both.

1. Multiple Each Item in a List by 2

The map function takes each element in the list and applies it to the corresponding function. In this example, we take each element and multiply it by 2. This will return a list of equivalent size, compare to o

#Note for Programming in Scala

##Chp.0 SBT & Scala Interpreter

Call scala interpreter by sbt.
```
// enter scala interpreter
```

In the below keyboard shortcuts, I use the capital letters for reading clarity but this does not imply shift, if shift is needed, I will say shift. So ⌘ + D does not mean hold shift. ⌘ + Shift + D does of course.

Tabs and Windows

Function	Shortcut
New Tab	`⌘` + `T`
Close Tab or Window	`⌘` + `W` (same as many mac apps)
Go to Tab	`⌘` + `Number Key` (ie: `⌘2` is 2nd tab)
Go to Split Pane by Direction	`⌘` + `Option` + `Arrow Key`

There are certain files created by particular editors, IDEs, operating systems, etc., that do not belong in a repository. But adding system-specific files to the repo's .gitignore is considered a poor practice. This file should only exclude files and directories that are a part of the package that should not be versioned (such as the node_modules directory) as well as files that are generated (and regenerated) as artifacts of a build process.

All other files should be in your own global gitignore file:

Create a file called .gitignore in your home directory and add any filepath patterns you want to ignore.
Tell git where your global gitignore file is.

Note: The specific name and path you choose aren't important as long as you configure git to find it, as shown below. You could substitute .config/git/ignore for .gitignore in your home directory, if you prefer.

Useful Pandas Snippets

A personal diary of DataFrame munging over the years.

Data Types and Conversion

Convert Series datatype to numeric (will error if column has non-numeric values)
(h/t @makmanalp)

	#!/bin/bash
	#
	# Convert all new Jupyter notebooks to straight Python files for easier code
	# reviews.
	#

	for file in $(git diff --cached --name-only); do
	if [[ $file == *.ipynb ]]; then
	jupyter nbconvert --to script $file
	git add ${file%.*}.py

	How to manually setup flake8 as PyCharm external tool

	File / Settings / Tools / External Tools / Add
	Name: Flake8
	Program: $PyInterpreterDirectory$/python
	Parameters: -m flake8 --max-complexity 10 --ignore E501 $FilePath$
	Working directory: $ProjectFileDir$

	Output Filters / Add
	Name: Filter 1

	"""
	In jupyter notebook simple logging to console
	"""
	import logging
	import sys

	logging.basicConfig(stream=sys.stdout, level=logging.INFO)

	# Test
	logger = logging.getLogger('LOGGER_NAME')

	#!/usr/bin/env python
	# vim: set fileencoding=utf8 :
	```
	$ pip install -U boto3 retrying
	$ export AWS_DEFAULT_PROFILE=test
	$ cat foo.sql
	select count(*)
	from bar
	$ python athena.py foo.sql
	$ ls -1

	"""Example to show how to plot histogram with accumulate ratio.

	Plot multiple histogram using seaborn.FacetGrid()
	"""
	import numpy as np
	import pandas as pd
	import matplotlib.pyplot as plt
	import seaborn as sns

	% matplotlib inline