import.qmd

---
title: "Import Data"

date-modified: 'today'
date-format: long

license: CC BY-NC  
bibliography: references.bib
---

::: callout-warning
## Did you start with a Project?

Reproducibility starts at the [foundation](proj.html#reproducibility)! Always begin by opening a project. See [New Projects](proj.html) for tips.

We **recommend** entering your code in **code-chunks** within [**coding notebooks**](quarto.html#notebooks---recomended).
:::

In this workshop we recommend the [Tidyverse](https://tidyverse.org) approach to learning and using R

Below are some of the core [*tidyverse*](https://tidyverse.tidyverse.org/) packages that are loaded with the function: `library(tidyverse)`.

| package   | use                               | package     | use                           |
|--------------|------------------------|--------------|---------------------|
| `dplyr`   | data wrangling                    | `forcats`   | categorical data / factors    |
| `ggplot2` | visualization                     | `lubridate` | dates and times               |
| `readr`   | import CSV                        | `stringr`   | regular expressions / strings |
| `purrr`   | iteration / functional programing | `tidyr`     | pivot data                    |
| `readxl`  | import Excel files                | `haven`     | import SPSS/Stata/SAS         |

## Data import wizard

The data import wizard is a quick and easy way to import your data

[![Import dataset](images/data_import.jpg){fig-alt="import dataset"}](images/data_import.jpg)

It's actually way **better** to follow the **reproducible steps** -- and hardly any more effort -- below...

## Load library packages

Open a Quarto document, Insert a code-chunk (Ctrl-Alt-I) and copy the following code. Then execute the code. You may first have to [install the tidyverse-package](packages.html#install-packages) if you have not already[^1].

[^1]: In R, a package is a collection of R functions, and/or data, and/or documentation. R users find and install packages via centralized package-hubs (e.g. [Metacran](https://www.r-pkg.org/), CRAN, [Bioconductor](https://bioconductor.org/), [R-universe](https://r-universe.dev/search/), Github) to aid in the specialization and efficiency of R coding.

```{r}
#| warning: false
#| message: false
library(tidyverse)
```

## Import data

In RStudio, in the Files quadrant and tab, click the `data` folder, then left-click the `brodhead_center.csv` file. Using the context menu, choose the *Import Dataset...* option. Once inside the data wizard, you can copy the code int he code-preview window, then paste the code into the code chunk of your quarto document or r script.

::: column-margin
```{=html}
<iframe width="300" height="200" src="https://www.youtube.com/embed/BKDkj7I4L-Y" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
```
:::

```{r}
#| label: import-data
#| warning: false
#| message: false
# library(readr)
brodhead_center <- read_csv("data/brodhead_center.csv")
# view(brodheadCenter)
```

::: callout-tip
## Composing the data import code...

Writing the import data function can be tricky. Try the import wizard pictured above. THEN, paste the code from the **Code Preview** section into your script.

[![Easily write import data function](images/data_import_code.jpg){fig-alt="Easily write import data function" width="800"}](images/data_import_code.jpg)
:::

## Excel, SPSS, SAS, etc.

The data import wizard will help you find the proper package for importing your data. For example, use...

-   `library(readxl)` for Excel data
-   `library(haven)` for SPSS, SAS, Stata
-   `lirary(readr)` for CSV or other delimeters

Just start with `File > Import Dataset` to get started composing that code, then paste your code into a script.

## Look at the data object

Now that you've [assigned](index.htm#pipes-and-assignment "Assign and object with <-") the output from the `read_csv` function to the name `brodhead_center`, simply call that object name in a code chunk.

```{r}
brodhead_center
```

## Visualize your data with {[ggplot2](https://ggplot2.tidyverse.org)}

Here's a quick teaser on visualizing data. Read more in the [visualization chapter](viz.html).

```{r}
#| warning: false
#| message: false
brodhead_center |> 
  ggplot(aes(x = name, y = cost)) +
  geom_boxplot() 
```

```{r}
#| warning: false
#| message: false
brodhead_center |> 
  filter(name != "Tandoor") |> 
  ggplot(aes(x = rating, y = cost)) +
  geom_jitter(aes(color = name))
```

```{r}
#| code-fold: true
#| code-summary: "Show the code"
brodhead_center |> 
  drop_na(rating, cost, name) |> 
  filter(name != "Tandoor") |> 
  ggplot(aes(x = factor(rating), y = cost)) +
  geom_tile(aes(fill = name), alpha = .3) +
  scale_y_continuous(label = scales::dollar) +
  scale_fill_brewer(palette = "Dark2") + 
  labs(x = "rating", y = NULL, title = "Heatmap: cost over ratings", 
       caption = "Source: https://github.com/data-and-visualization/Intro2R",
       fill = "Restaurant name") +
  theme_classic() +
  theme(plot.title.position = "plot")
  
```