session-csv.qmd

---
title: "Introduction to R and Rstudio"
subtitle: "Session - import csv"
---


## Getting data into to R

There are packages to import all types of data and RStudio has wizards for just a few of the possibilities.

We are going to first import a csv using the wizard but also get the code to copy to scripts for reproducibility.

## Import wizard

We will use the "Import Dataset" button (but you can also click on the file itself):

<img src="img/session03/import-screenshot.PNG" alt="Screenshot of RStudio with Import Dataset drop down button highlighted as well as the file capacity_ae.csv in the Files tab." class="center" width="80%"/>

## Two ways of importing csv

The base R doesn't use any packages but imports a `data frame` in R whereas {readr} is built on the base R and creates a neater `tibble`

<img src="img/session03/drop-down-import.PNG" alt="Screenshot of the drop down menu when Import Dataset is selected in RStudio. From Text (readr)... is highlighted." class="center" width="60%"/>

## tibble = data frame

`tibble` is synonymous with `data frame` but acts differently

> A tibble... is a modern reimagining of the data.frame...
>
> Tibbles are data.frames that are **lazy and surly**: they do less (i.e. they don't change variable names or types, and don't do partial matching) and **complain more** (e.g. when a variable does not exist).
>
> This forces you to confront problems earlier, typically leading to cleaner, more expressive code.

https://tibble.tidyverse.org/)

## Find the file

Locate the file `capacity_ae.csv`

<img src="img/session03/wizard.PNG" alt="Screenshot of the blank import dataset wizard with the Browse... to locate files highlighted."/>

## Data preview

When the file is located {readr} is used automatically and the data preview populates

<img src="img/session03/capacity-ae-preview.PNG" alt="Screenshot of Import Text wizard with file selected and data in the preview."/>

## Getting the code for later

Whilst it's possible just to select import, RStudio gives you the option to copy the code:

<img src="img/session03/copy-wizard-code.PNG" alt="Screenshot of the code highlighted from the Import Wizard in RStudio."/>

# Running the code

In the editor, once copied from the wizard or shared in a script:

```{r}
library(readr) # Good practice to put this at the top of a script

capacity_ae <- read_csv("capacity_ae.csv")
```

## End session