Finding Help

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# Finding Help
## ⚔<br/>in the R wilderness
### Julia Piaskowski
### 2022-03-03

---

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## What do you do when you need to solve a problem in R?

![who ya gonna call](images/ghostbusters.jpeg)

---
# Check the documentation!

How do we do this?

```r
?par
??plot
```

(*Remember, you can spend 2 hours searching the web in order to save 15 minutes of reading the documentation).*

---
# No really, read the docs

2 main aspects of documentation:

1. Function reference
1. Vignettes

[CRAN](https://cran.r-project.org/web/packages/available_packages_by_name.html) can be a good place to start.

[tidyr example](https://CRAN.R-project.org/package=tidyr)

---
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## [exercise](exercises/exercise-3.html)

---
# Read your error messages

*They are often telling you something important.*

<div class="figure">
<img src="images/tweet_ignored_error.png" alt="Informative error message I ignored" width="80%" />
<p class="caption">Informative error message I ignored</p>
</div>

---
# Still, error messages can be confusing

![confused man meme at R error](images/r_function_error.jpg)

---
## Other help options

[RStudio Community](https://community.rstudio.com/)  
<br>  
![rstudio community screenshot](images/rstudio_community.png)

---
## Other help options

[R4DS community](https://www.rfordatasci.com/)  
<br>   
![R for DS community screenshot](images/r4ds_screenshot.png)

---
## Other help options

[Stack overflow](https://stackoverflow.com/)  
<br>  
![stack overflow screen shot](images/stackoverflow_screenshot.png)

---
# Read the source code

![read the source, luke](images/luke_source_code.jpeg)

*(this will help improve your coding, too)*

---
# How to find source code

* Type the function name in the console without parentheses:

```r
lm
```
*[suppressed output because it is long]*
<br><br>

* Sometimes this is not informative

```r
c
```

```
## function (...)  .Primitive("c")
```

```r
subset
```

```
## function (x, ...) 
## UseMethod("subset")
## <bytecode: 0x55f9840d3de0>
## <environment: namespace:base>
```

```r
`[`
```

```
## .Primitive("[")
```

---
# Use 'lookup' to find what you need

*(Prior to 'lookup', finding source code was a real [bugger](https://github.com/jennybc/access-r-source#readme)*

**lookup** checks CRAN, Bioconductor and GitHub!

```r
lookup::lookup(`[`)
```

---
#  Miscellaneous R tip

#### How to find other methods associated with an R object
--

All R objects have a class assigned to them:

```r
y <- rnorm(20); x <- y + rnorm(20)
m <- lm(y ~ x)
class(m)
```

```
## [1] "lm"
```

---

Once you know the object class, you can search on methods written for that class.

```r
methods(class = "lm")
```

```
##  [1] add1           alias          anova          case.names     coerce        
##  [6] confint        cooks.distance deviance       dfbeta         dfbetas       
## [11] drop1          dummy.coef     effects        extractAIC     family        
## [16] formula        hatvalues      influence      initialize     kappa         
## [21] labels         logLik         model.frame    model.matrix   nobs          
## [26] plot           predict        print          proj           qr            
## [31] residuals      rstandard      rstudent       show           simulate      
## [36] slotsFromS3    summary        variable.names vcov          
## see '?methods' for accessing help and source code
```