R Console and script files in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Hello, world!" in the R console.

R Programming

print([1])

Drag options to blanks, or click blank then click option'

AHello, world!

B"Hello, world!"

Cprint("Hello, world!")

DHello

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the text.

Putting the whole print statement inside print().

In R, to print text, you use print() with the text inside quotes.

2fill in blank

medium

Complete the code to assign the number 10 to a variable named x.

R Programming

x [1] 10

Drag options to blanks, or click blank then click option'

A=

B==

C<-

D->

Attempts:

3 left

💡 Hint

Common Mistakes

Using == which is for comparison, not assignment.

Using = which works but <- is preferred style.

In R, the preferred way to assign a value to a variable is using the <- operator.

3fill in blank

hard

Fix the error in the code to correctly run a script file named "script.R".

R Programming

source([1])

Drag options to blanks, or click blank then click option'

A"script.R"

Bscript

Cscript.R

D'script.R'

Attempts:

3 left

💡 Hint

Common Mistakes

Not putting the filename in quotes.

Using the filename without extension.

The source() function requires the filename as a string inside quotes.

4fill in blank

hard

Fill both blanks to create a vector of numbers from 1 to 5 and print it.

R Programming

numbers <- [1]([2])

Drag options to blanks, or click blank then click option'

Ac

B1:5

Cseq

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using seq without parameters.

Not using c() to create a vector.

Use c() to combine numbers into a vector. 1:5 creates numbers from 1 to 5.

5fill in blank

hard

Fill all three blanks to read a CSV file named "data.csv", assign it to a variable, and print the first rows.

R Programming

[1] <- read.csv([2])
head([3])

Drag options to blanks, or click blank then click option'

Amy_data

B"data.csv"

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Not putting filename in quotes.

Using different variable names inconsistently.

Assign the result of read.csv() to a variable, then use head() to print first rows.

Practice

1. What is the main purpose of the R Console?

easy

A. To type and run commands one at a time

B. To save many commands in a file

C. To create graphical plots only

D. To install R packages automatically

Solution

1. Step 1: Understand the R Console function

   The R Console allows users to type commands and see results immediately, one command at a time.

2. Step 2: Compare with script files

   Script files are used to save many commands to run later, not the console's main role.

3. Final Answer:

   To type and run commands one at a time -> Option A

4. Quick Check:

   R Console = run commands one by one [OK]

Hint: Console runs commands instantly, scripts save commands [OK]

Common Mistakes:

• Confusing console with script file
• Thinking console saves commands permanently
• Assuming console only creates plots

2. Which of the following is the correct way to run a script file named analysis.R in R?

easy

A. execute("analysis.R")

B. run("analysis.R")

C. source("analysis.R")

D. load("analysis.R")

Solution

1. Step 1: Recall R function to run scripts

   In R, the function source() is used to run commands saved in a script file.

2. Step 2: Check other options

   Functions like run(), execute(), and load() do not run script files; load() loads saved data, not scripts.

3. Final Answer:

   source("analysis.R") -> Option C

4. Quick Check:

   Run script = source() [OK]

Hint: Use source() to run saved R scripts [OK]

Common Mistakes:

• Using load() to run scripts
• Trying run() or execute() which don't exist
• Forgetting to use quotes around filename

3. What will be the output when you run the following commands in the R Console?

x <- 5
y <- 3
z <- x + y
print(z)

medium

A. NULL

B. 53

C. Error: object 'z' not found

D. 8

Solution

1. Step 1: Calculate the sum of x and y

   x is assigned 5, y is assigned 3, so z = 5 + 3 = 8.

2. Step 2: Print the value of z

   The print(z) command outputs the value stored in z, which is 8.

3. Final Answer:

   8 -> Option D

4. Quick Check:

   5 + 3 = 8 [OK]

Hint: Add variables then print result [OK]

Common Mistakes:

• Concatenating numbers as strings (53)
• Forgetting to assign z before print
• Expecting NULL output

4. You wrote this script file calc.R:

result <- a + b
print(result)

When you run source("calc.R") in the console, you get an error. What is the problem?

medium

A. Variables a and b are not defined before use

B. The print() function is misspelled

C. source() cannot run script files

D. The assignment operator <- is incorrect

Solution

1. Step 1: Check variable definitions

   The script uses variables a and b without assigning values first, causing an error.

2. Step 2: Verify other parts

   print() is correct, source() runs scripts, and <- is valid assignment in R.

3. Final Answer:

   Variables a and b are not defined before use -> Option A

4. Quick Check:

   Undefined variables cause errors [OK]

Hint: Define variables before using them in scripts [OK]

Common Mistakes:

• Assuming print() is wrong
• Thinking source() can't run scripts
• Confusing assignment operator syntax

5. You want to organize your R work by saving commands in a script file and running them all at once. Which approach is best?

hard

A. Use load() to run commands saved in a script

B. Write commands in a script file and use source() to run them

C. Save commands in a text file and open it in a text editor only

D. Type all commands directly in the console one by one

Solution

1. Step 1: Understand script file usage

   Script files save many commands so you can run them together later.

2. Step 2: Use source() to run scripts

   The source() function runs all commands in the script file at once.

3. Step 3: Evaluate other options

   Typing in console is manual and slow; text files alone don't run commands; load() loads data, not scripts.

4. Final Answer:

   Write commands in a script file and use source() to run them -> Option B

5. Quick Check:

   Scripts + source() = organized runs [OK]

Hint: Save commands in script, run with source() [OK]

Common Mistakes:

• Running scripts by typing manually
• Using load() instead of source()
• Not saving commands in R script format