---
title: "Dataset requirements to make Kaplan-Meier plot with RcmdrPlugin.KMggplot2"
author: "Triad sou."
date: "2016-01-04"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Dataset requirements for Kaplan-Meier plot}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

`RcmdrPlugin.KMggplot2` depends `survfit` function of `survival` package.
Dataset requirements are same as `survfit` function, which works with `Surv` objects.


## `Surv` object

`Surv` objects are generated from `Surv` function.
`RcmdrPlugin.KMggplot2` calls as follows:

```r
survfit(Surv(time = x, event = y, type = "right") ~ z + s + t, .df)
```

### Arguments
* `time`
    * The follow up time variable.
* `event`
    * The status indicator variable, 0 = alive (censor), 1 = dead (event).
* `type`
    * Character string specifying the type of censoring. `RcmdrPlugin.KMggplot2` can only handle "right" censoring.
* `z`, `s`, `t`
    * The stratum (`z`) and the facet (`s`, `t`) variables (factor variables).
* `.df`
    * A data frame for plotting.
    
    
`RcmdrPlugin.KMggplot2` requires a data frame that at least includes `time` and `event` variables, and includes `z`, `s`, `t` if you needs


## Data Example

```{r, echo=FALSE, results='asis'}
data(dataKm, package = "RcmdrPlugin.KMggplot2")
exampleData <- dataKm[, c("time", "event", "trt", "sex", "marker")]
knitr::kable(head(exampleData, 10))
```

In this case: 

* `time`: "time"
* `event`: "event" (0 = alive (censor), 1 = dead (event))
* `z`, `s`, or `t`: "trt", "sex", or "marker"
