heronshoes/red_amber

---
title: RedAmber Examples
date: 2023-08-06
author: heronshoes
jupyter: ruby
format:
  pdf:
    toc: true
---

This notebook walks through the [README of RedAmber](https://github.com/heronshoes/red_amber#readme).

## `RedAmber::DataFrame`

```{ruby}
#| tags: []
require 'red_amber'
include RedAmber
require 'datasets-arrow'

{RedAmber: VERSION, Datasets: Datasets::VERSION}
```

## Example: diamonds dataset

For the first loading of Datasets::Diamonds, it will take some time to download.

```{ruby}
#| tags: []
dataset = Datasets::Diamonds.new
diamonds = DataFrame.new(dataset)
```

```{ruby}
#| tags: []
df = diamonds
  .slice { carat > 1 } # or use #filter instead of #slice
  .group(:cut)
  .mean(:price) # `pick` prior to `group` is not required if `:price` is specified here.
  .sort('-mean(price)')
```

```{ruby}
#| tags: []
usdjpy = 110.0 # when the yen was stronger

df.rename('mean(price)': :mean_price_USD)
  .assign(:mean_price_JPY) { mean_price_USD * usdjpy }
```

## Example: starwars dataset

```{ruby}
#| tags: []
uri = URI('https://vincentarelbundock.github.io/Rdatasets/csv/dplyr/starwars.csv')

starwars = DataFrame.load(uri)
```

```{ruby}
#| tags: []
starwars
  .drop(0) # delete unnecessary index column
  .remove { species == "NA" } # delete unnecessary rows
  .group(:species) { [count(:species), mean(:height, :mass)] }
  .slice { count > 1 } # or use #filter instead of slice
```

## `RedAmber::Vector`

```{ruby}
#| tags: []
penguins = DataFrame.new(Datasets::Penguins.new)
```

```{ruby}
#| tags: []
penguins[:bill_length_mm]
```

```{ruby}
#| tags: []
penguins[:bill_length_mm] < 40
```

```{ruby}
#| tags: []
penguins[:bill_length_mm].mean
```