# Basics of R

Find the solution to these exercises **without** using R.

**Exercise 1:** Write the output.

```
4:8
```

## Answer

4 5 6 7 8

**Exercise 2:** Write the output.

```
3 * c(3, 4)
```

## Answer

9 12

**Exercise 3:** Write the output.

```
sqrt(25)
```

## Answer

5

**Exercise 4:** Write the output.

```
hello <- 6
Hello <- 4
hello
```

## Answer

6

**Exercise 5:** Solve the problem.

```
round(sum(vector)
```

## Answer

it lacks the last parenthesis `)`

**Exercise 6:** Solve the problem.

```
data.frame(country = c("Germany", "Argentina", "China"),
lifeexp = c(81.2, 76.2, 73.1)
```

## Answer

it lacks the last parenthesis `)`

**Exercise 7:** Solve the problem(s).

```
country <- c("Germany". "Argentina", "China"),
lifeexp <- c(81.2, 76.2, 73.1)
data.frame(country, lifexp)
```

## Answer

a point separates Germany and Argentina

the comma at the end of the first line should be removed

**Exercise 8:** Write the output.

```
c(TRUE, 4)
```

## Answer

1 4

**Exercise 9:** Does this produce a character, numeric or logical vector?

```
c(TRUE, 4)
```

## Answer

numeric vector

**Exercise 10:** What is the output of the following code?

```
c(FALSE, "One", 2)
```

## Answer

“FALSE” “One” “2”

**Exercise 11:** Does this produce a character, numeric or logical vector?

```
c(FALSE, "One", 2)
```

## Answer

character vector

**Exercise 12:** Write the output.

```
numbers <- c(10,6,12,17,5)
numbers[3,5]
```

## Answer

12 5

**Exercise 13:** Write the output.

```
numbers <- c(3,22,4,23,5)
numbers[2:3]
```

## Answer

22 4

**Exercise 14:** Which rows and columns do we select?

```
dataframe[c(1,4), ]
```

## Answer

1st and 4th row, all columns

**Exercise 15:** Which rows and columns do we select?

```
dataframe[ ,"country"]
```

## Answer

All rows, the column named “country”

**Exercise 16:** Write the output.

```
numbers <- c(3.55, 4.99, 5.62)
round(numbers)
```

## Answer

4 5 6

**Exercise 17:** Write the output.

```
max(c(3.55, 4.99, 5.62))
```

## Answer

5.62

**Exercise 18:** Write the output.

```
max(sum(c(3.5, 6.5)))
sum(max(c(3.5, 6.5)))
```

## Answer

10 6.5

**Exercise 19:** Write the output.

```
as.numeric(c(FALSE, TRUE))
```

## Answer

0 1

**Exercise 20:** Write the output.

```
as.integer(6.2)
```

## Answer

6

**Exercise 21:** Write the output.

```
as.integer(factor(c("Argentina", "Zambia", "Congo")))
```

## Answer

1 3 2

**Exercise 22:** Write the output.

```
end <- c(5, 9, 3)
as.numeric(end > 6)
```

## Answer

0 1 0