Enrollment.csv

Many of the CSVs in the HMIS CSV may contain multiple rows per client. This can make it difficult when working with HMIS data, as it appears to the non-data person there are duplicates within your data.

Let's look at some dataframes:

enrollmentDf

Notice how Bob has two records? One on 10/17/2016 and 01/01/2013. This represents two HUD Entry Assessments completed on Bob. These HUD Entry Assessments could represent two stays in ...

R let's us work with HMIS data, but there is still the problem of how to load the data into R from a source. R is actually pretty neat regarding data importing. We can load data from a website, SQL database, text file, Excel file, or CSV.

When working with HMIS data the two most common types of data source are Excel and CSV. Therefore, it's going to pay to spend a little time on how to bring those files into R.

Importing CSVs into R

CSV stand for Comma Separated Value format. It is a near ancient file format ...

Mixing R and SQL is powerful. One of the easiest ways to implement this combination is with the R library SQLdf.

If TL;DR, skip to Coerce Date Types into Strings before Passing to SQLdf at bottom.

SQLdf

The power of SQLdf comes from its ability to convert dataframes into SQLite databases on the fly. To the user, it doesn't appear like anything special is going on, but under the hood R is working together with a SQLite client to create a table which can be queried and manipulated with ANSI SQL calls.

For example,

dataFrame1 <- read.csv(pathToData)
library ...

Creating a List of Domestic Violence Victims

In this first work challenge you will use R and SQL to get a by-name-list of those who are domestic violence victims from an HMIS data pull (5.1).

Data Needed

The HMIS Data Pulls are simply a relational database which are broken into multiple CSVs. These CSVs will change in formatting, as stipulated by HUD. The current version of these CSVs is 5.1. For this work challenge the focus will be on two CSVs.

1. Client.csv
2. HealthAndDV.csv

The Client file will contain one row per client and only one row ...

The R and SQL Way

Below is my attempt to describe the method I use to get at HMIS data. In short, I'm mixing two powerful data languages to get answers from a data set quickly.

What is SQL?

SQL stands for Structured Query Language. Which can be translated as, "Asking a question a computer could understand." This computer language was designed to get data off a remote relational database .

A sample of what SQL looks like:

SELECT Data FROM DataSet WHERE Data='BlueEyes'

SQL Pros:

• Easy to understand
• Can be learned quickly
• Powerful in merging data sets

SQL Cons ...

For a long time now I've put off learning JavaScript. It really never interested me. I'd like to say it was the thought, "Oh, JavaScript is for web developers and I'm embedded all the way!" But that wasn't really it. I think it hasn't appealed to me because I couldn't connect it to hardware. Well, at least, that was my assumption.

However, I've recently discovered Google's Web APIs. Specifically, their Bluetooth Low Energy API.

• Google's Bluetooth Web API

It's pretty amazing. It allows a developer to write asynchronous JavaScript using Promises to get into the hardware of the client's PC ...

This is an R script which will take two sets of HMIS 5.1 CSVs and produce a combined set.

A few notes:

1. A new ExportID will need to be provided.
2. Each files are deduplicated based upon the Primary Key (ProjectEntryID, PersonalID, etc.)
3. The Project.csv contains a PITCount which is different based upon the date ranges the two data sets were pulled.  However, the script takes the maximum of the two PITCounts.
4. It requires HMIS_Functions and dplyr.

    library(dplyr)
    # hmisFunctions <- "/Users/user//Dropbox/HMIS/HMIS_R_Functions/HMIS_R_Functions.R"
    # dataPathOne <- "/Users/user//Dropbox/HMIS/R HMIS CSV Set Merger/HMIS Data ...

One of the issues I've had in the past with the Lumi projects is manageable UI.  The project will start out pretty straight foward, but soon, I'm switching between device types, checking if hardware is ready, and routing callbacks based upon the device selected.  It becomes spaghetti code quick.  On Lumi4, I've decided to bite the bullet and implement MVVM .

After about 20 hours struggling with setting up Lumi4 as an MVVM project I've dervied two conclusions:

1. It's possible
2. Apple spoils developers with MVC baked into Xcode

MVVM in C# and UWP isn't simple.  It seems like there is a ...

Unit and Integration Testing

I mentioned in an earlier entry that I had the hardest time differentiating between unit and integration tests.  But this distinction was critical for implementing tests which could cover frameworks designed to interact with embedded systems.  At least, in my perspective.  Below is an outline of how I'm structuring tests for the Lumi4 code base.

Lumi4.Tests

The unit tests namespace will contain all tests which cover methods which can be operate independtly, without communication of any other system then the program itself.

For example,

    [TestClass]
    public class Constructor
    {
        [TestMethod]
        public void WifiCentralManagerConstructor_Null_Exception()
        {
            bool ThrewNull = false ...