Working with R

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# Working with R
## Dr. Mine Dogucu

]

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## Reminder

- Close all apps on your computer.  
- Open slides for this session from the cluster website (https://cosmos-datascience.netlify.app).

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# Introductions

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# First things first:
- Do you have a computer?
- Do you have R on your computer?
- Do you have RStudio on your computer?

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# A Walkthrough of RStudio
### Why it's a nice environment for R coding

It is an IDE(Integrated Development Environment) which we use to manage and execute R code.

It is open-source and free, and incoperated with other platforms.

### Create a new document in which to do R coding

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# R review
## Object assignment operator

``` r
birth_year <- 2007
```

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# R review

R is case-sensitive

``` r
my_age <- 2024 - birth_year

My_age
```

```
## Error in eval(expr, envir, enclos): object 'My_age' not found
```

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## Variables in R

`character`: takes string values (e.g. a person's name, address)

`integer`: integer (single precision)

`double`: floating decimal (double precision)

`numeric`: integer or double

`factor`: categorical variables with different levels(AD, no AD)

`logical`: TRUE (1), FALSE (0)

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## Variables in R

typeof is the function we use to check the type

``` r
typeof(1)
```

```
## [1] "double"
```

``` r
typeof(1L)
```

```
## [1] "integer"
```

``` r
typeof(as.integer(1))
```

```
## [1] "integer"
```

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# R review

If something comes in quotes, it is not defined in R.

``` r
ages <- c(25, my_age, 32)

names <- c("Menglin", "Mine", "Rafael")

data.frame(age = ages, name = names)
```

```
##   age    name
## 1  25 Menglin
## 2  17    Mine
## 3  32  Rafael
```

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# R review
## Functions and Arguments

``` r
do(something)
```

`do()` is a function;   
`something` is the argument of the function.

``` r
do(something, colorful)
```

`do()` is a function;   
`something` is the first argument of the function;   
`colorful` is the second argument of the function.

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# R review

## Getting Help

In order to get any help we can use `?` followed by function (or object) name.

``` r
?c
```

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# Some basic data structures
- variables/assignment
- combine/vector
- matrix

``` r
temp_variable = 1
temp_vector = c(1, 2, 3)
temp_matrix = matrix(c(1,2,3,4), nrow=2, ncol=2, 
                     byrow=TRUE)
```