---
title: "Spreading and Gathering"
output:
  word_document: default
  pdf_document: default
  html_notebook: default
---

```{r message=FALSE}
library(tidyverse)
```

Nice Example:  Here is a nice example from the [tidyr](https://tidyr.tidyverse.org/reference/spread.html) website.

```{r}
set.seed(12345)

stocks <- data.frame(
  time = as.Date('2009-01-01') + 0:9,
  X = rnorm(10, 0, 1),
  Y = rnorm(10, 0, 2),
  Z = rnorm(10, 0, 4)
)

stocks
```

```{r}
stocksm <- stocks %>% gather(stock, price, -time)
stocksm
```


```{r}
stocksm %>% spread(stock, price)
#>          time           X           Y          Z
#> 1  2009-01-01 -0.25148344  0.03835518 -0.9835856
#> 2  2009-01-02  0.44479712  0.05912151 -4.7102532
#> 3  2009-01-03  2.75541758  1.09965508 -3.9034025
#> 4  2009-01-04  0.04653138 -4.54822971  4.2602293
#> 5  2009-01-05  0.57770907  5.36511437  0.5266825
#> 6  2009-01-06  0.11819487 -0.72244251  1.9545152
#> 7  2009-01-07 -1.91172049  0.42671150 -6.7978023
#> 8  2009-01-08  0.86208648  2.14869176 -5.8829452
#> 9  2009-01-09 -0.24323674 -1.33017650  1.1366014
#> 10 2009-01-10 -0.20608719  2.22790484  5.3492817
```

```{r}
stocksm %>% spread(time, price)
#>   stock  2009-01-01  2009-01-02 2009-01-03  2009-01-04 2009-01-05 2009-01-06
#> 1     X -0.25148344  0.44479712   2.755418  0.04653138  0.5777091  0.1181949
#> 2     Y  0.03835518  0.05912151   1.099655 -4.54822971  5.3651144 -0.7224425
#> 3     Z -0.98358565 -4.71025324  -3.903402  4.26022928  0.5266825  1.9545152
#>   2009-01-07 2009-01-08 2009-01-09 2009-01-10
#> 1 -1.9117205  0.8620865 -0.2432367 -0.2060872
#> 2  0.4267115  2.1486918 -1.3301765  2.2279048
#> 3 -6.7978023 -5.8829452  1.1366014  5.3492817
```


# Download some stock market data.  Nice and tidy.

Using [quantmod](http://www.quantmod.com/)

```{r message=FALSE}
library(quantmod)
```


```{r}
getSymbols("GOOG",src="yahoo") # from yahoo finance 
```

```{r}
getSymbols("GOOG",src="yahoo") 
barChart(GOOG) 
```

```{r}
GOOG %>% head()
```



We will use the [BatchGetSymbols](https://cran.r-project.org/web/packages/BatchGetSymbols/vignettes/BatchGetSymbols-vignette.html) R package to download stock market data.

```{r}
library(BatchGetSymbols)
library(tidyverse)
```


```{r}
# set dates
first.date <- Sys.Date() - 10
last.date <- Sys.Date()

# set tickers
tickers <- c('F','Goog','AAPL')

l.out <- BatchGetSymbols(tickers = tickers, 
                         first.date = first.date,
                         last.date = last.date, 
                         cache.folder = file.path(tempdir(), 
                                                  'BGS_Cache') ) # cache in tempdir()
```


```{r}
print(l.out$df.control)
```

Is the data in a tidy format?

```{r}
print(l.out$df.tickers)
```


```{r}
l.out$df.tickers %>% ggplot(aes(x = ref.date, y = price.close)) +
   geom_line() +
   facet_wrap(~ticker, scales = 'free_y') 
```