Methods_1.Rmd

---
title: "Falls in MrOS"
author:
  
  Marty Arrigotti^[OHSU-PSU School of Public Health]
  
  Tyler Bennett^[OHSU-PSU School of Public Health]
  
  Anna Booman^[OHSU-PSU School of Public Health]
  
  Colin Hawkinson^[OHSU-PSU School of Public Health]
  
  Matthew Hoctor^[OHSU-PSU School of Public Health]
  
date: "6/2/2021"
output:
  html_document:
    number_sections: no
    theme: lumen
    toc: yes
    toc_float:
      collapsed: yes
      smooth_scroll: no
  pdf_document:
    toc: yes
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r, libraries}
library(tidyverse)
library(purrr)
library(readxl)

```

```{r user functions}
MrOs <- readxl::read_excel("MrOS_Baseline_Falls_Project.xlsx")
glimpse(MrOs)
skimr::skim(MrOs)
obj_classes <- c()
for(i in seq(1:length(MrOs))) {
  obj_classes = c(obj_classes, class(MrOs[[1,i]]))
}
obj_classes

```

We'll consider every variable in the data frame other than patient ID as a candidate variable for the model. We'll use Portland as the referent group for when site is considered as a categorical variable. 

```{r 1. variable }
unique(MrOs$site)
MrOs <- MrOs %>% 
  mutate(st_1 = case_when(
    site = "PO" ~ 0
    site = "BI" ~ 1
    site = "MN" ~ 0 
    site = "PA" ~ 0
    site = "PI" ~ 0
    site = "SD" ~ 0
  )) %>% 
  mutate(st_2 = case_when(
    site = "PO" ~ 0
    site = "BI" ~ 0
    site = "MN" ~ 0
    site = "PA" ~ 1
    site = "PI" ~ 0
    site = "SD" ~ 0
  )) %>%   
  mutate(st_3 = case_when(
    site = "PO" ~ 0
    site = "BI" ~ 0
    site = "MN" ~ 0
    site = "PA" ~ 0
    site = "PI" ~ 1
    site = "SD" ~ 0
  )) %>% 
  mutate(st_4 = case_when(
    site = "PO" ~ 0
    site = "BI" ~ 0
    site = "MN" ~ 0
    site = "PA" ~ 0
    site = "PI" ~ 0
    site = "SD" ~ 1
  ))

```

Check the number of unique observations within each level for each candidate variable... 

```{r 2.}
# unique(MrOs[2])
class(as.character(MrOs[2]))
class(MrOs$site)

# head(MrOs)
# unique(MrOs$mhstrk)
# length(MrOs$mhstrk[MrOs$mhstrk == 0])
# length(MrOs$mhstrk[MrOs$mhstrk == 1])

ls_1 <- c()
for (i in (MrOs)) {
  d = c()
  for (unique in unique(i)) {
    d = c(d, length(i[i == un]))
    ls_1 = c(ls_1, d)
  }
  
}
ls_1

```