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---
title: "An introduction to using functions in R"
author: "Cameron M. Nugent"
date: "2019-10-17"
---

## Introduction

R is considered to be a functional programming language. What this means is that the syntax and rules of the language are most effective when you write code built around the use of functions. They allow you to modularize code, thereby isolating different blocks in a way that makes your code more generalized, reuseable, readable and easier to debug. This post is meant to introduce the three basic parts of a function (the arguments, the body and the environment), demonstrate some of the rules that govern function behaviour and provide a launchpad to help you get started writing functions in your own R code.

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# for a recent tutorial at the university of guelph R users group, I was going through
# how to generate summary stats & tidy dataframes from messy data sources

# we were working with text data, and the exercise I designed called for us to process
# a series of sentences and answer 3 questions about each line:
# is the line dialouge (by presence of a quotation mark)
# is the line a question (by presence of a question mark) and 
# what is the word count of the line

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#original undecorated
class example_class:
	def __init__(self, *, kw1 = None, kw2 = None):
		if kw1 is not None or kw2 is not None:
			#do stuff with the args
			self.kw1 = kw1
			self.kw2 = kw2

	def read(self, *, kw1 = None, kw2 = None):	
		if kw1 is not None or kw2 is not None:

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# ORIGINAL version


def merge_sorted(list_a, list_b):
	""" take two lists of integers sorted smallest to largest, 
		merge them to a single output list with
		no duplicate values """
	
	output_list = []

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from datetime import datetime
from concurrent import futures

import pandas as pd
from pandas import DataFrame
import pandas_datareader.data as web

def download_stock(stock):
	""" try to query the iex for a stock, if failed note with print """
	try:

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from datetime import datetime

import pandas as pd
from pandas import DataFrame
import pandas_datareader.data as web

def download_stock(stock):
	""" try to query the iex for a stock, if failed note with print """
	try:
		print(stock)

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