Nested Data

class: center, middle, inverse, title-slide

# Nested Data

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## Nested Data

* A nested data frame stores individual tables within the cells of a larger, organizing table.

* Use a nested data frame to:

* preserve relationships between observations and subsets of data
    * manipulate many sub-tables at once with the purrr functions map(), map2(), or pmap().
    
<img src="myss/nestdata.png" width="70%" />

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### How to create a nested data frame:

1. Group the data frame into groups with dplyr::group_by()

2. Use nest() to create a nested data frame with one row per group

```r
knitr::include_graphics("myss/nesteddata2.png")
```

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### unnest()

```r
knitr::include_graphics("myss/unnest.png")
```

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## List Columns

```r
knitr::include_graphics("image/tb03_list-column/listcolumn.png")
```

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## List Column Workflow

```r
knitr::include_graphics("myss/listColumn2.png")
```

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## WORK WITH LIST COLUMNS

```r
knitr::include_graphics("myss/workwithcolumnlist01.png")
```

```r
knitr::include_graphics("myss/workwithcolumnlist02.png")
```

```r
knitr::include_graphics("myss/workwithcolumnlist03.png")
```

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```r
knitr::include_graphics("image/tb03_list-column/mapLogic.png")
```

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## Simplify the List column

```r
knitr::include_graphics("image/tb03_list-column/mapWalk.png")
```

---