decatur

# Python Cheat Sheet

# List Comprehension

some_items = [{'index':i, 'value':i*i} for i in range(0,10)]
filtered_items = [item for item in some_items if item['index']%2 == 1 ]

# Dict Comprehension

decatur

def topological(nodes:set, get_successors) -> deque:
    """
    Returs a topologically sorted queue using DFS and gray/black colors.
    get_successors(node) an accessor function for the successors of each node.
    
    Code based on https://gist.github.com/kachayev/5910538
    """
    GRAY, BLACK = 0, 1
    order, state = deque(), {}

decatur

$include rle.gms

Set T / 1*5 /;

* Test series without additional domain.
Parameter a(T), a_rle(T) / 1 1,      3 EPS, 5 2 /
          a_expected(T)  / 1 1, 2 1,        5 2 /;

a(T) = a_rle(T);
rle_decode_1(a, T);

decatur

# -*- coding: utf-8 -*-
"""
Copyright 2018-09-09, Wolfgang Kühn

Fast inter-process communication (ipc) for Python (CPython, PyPy, 2.7, 3.6+) on MS-Windows.
It uses shared memory and eventing.

Example rpc style synchronization:

Server (rpc provider):

decatur

from dataclasses import dataclass, field
from itertools import count
from datetime import datetime

counter = count()


@dataclass
class Event:
    message: str

decatur

"""
Use case save/restore with Pythonflow for long running data flow operations.
Pythonflow is a very lighter alternative to tensorflow's graphs.

Prerequisite:
$ pip install pythonflow

In this example, we model round(a+b) with two save points.

Our file-database will have the structure:

decatur

/**
 * In a daylight-saving time locale, this will generate 92, 96 or 100 values.
 * This function sideways some of JavaScript Date pitfalls
 * @param {string} localDateString
 * Example:
 *     generateQuarterHoursForLocalDate('2019-03-31').map(function(date) { return date.toJSON() })
 *     ->  0: "2019-03-30T23:00:00.000Z"
 *         1: "2019-03-30T23:15:00.000Z"
 *        ...
 *        91: "2019-03-31T21:45:00.000Z"

decatur

import numpy as np


class Plant:
    """
    KISS implementation of a time series data class with a ndarray backing.
    Think of Pandas with typing.
    Properties can be also set by scalar values.
    """
    def __init__(self, dim: int):

decatur

This a Chrome extension to make yammer feed pages more user friendly. As I personally do not trust extensions from the Chrome Web Store, this extension is only offered through this gist and must be installed in Developer Mode.

Setup

1. Download this gist to some folder my_yammer_extension_folder
2. Add this Chrome Extension according to Getting started - Chrome Developers:
   1. Open the Extension Management page by navigating to chrome://extensions.
   2. Enable Developer Mode by clicking the toggle switch next to Developer mode.
3. Click the LOAD UNPACKED button and select the my_yammer_extension_folder

decatur

What is a Python Application

A Python Application describes required packages, entry point and constraints for the operation and development process.

Operation

1. An entry point, e.g. my_app.my_module:App
2. Constraints for required packages AppR, e.g. {my_app=1.2.3, my_util=0.1.2, pandas=1.2.5, ...}

Development