Programming Example

Vector selection, another way of selection

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💻 Practical Program

📘 Step by Step Learning

Selecting multiple elements of poker_vector with c(2, 3, 4)is not very convenient. Many statisticians are lazy people by nature, so they created an easier way to do this: c(2, 3, 4) can be abbreviated to2:4, which generates a vector with all natural numbers from 2 up to 4.

So, another way to find the mid-week results is poker_vector[2:4]. Notice how the vector 2:4 is placed between the square brackets to select element 2 up to 4.

Instruction

Assign to roulette_selection_vector the roulette results from Tuesday up to Friday; make use of : if it makes things easier for you.

Program Code

# Poker and roulette winnings from Monday to Friday:
poker_vector <- c(140, -50, 20, -120, 240)
roulette_vector <- c(-24, -50, 100, -350, 10)
days_vector <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")
names(poker_vector) <- days_vector
names(roulette_vector) <- days_vector

# Define a new variable based on a selection
roulette_selection_vector <- poker_vector[2:4]

# See result
roulette_selection_vector

Output

> # Poker and roulette winnings from Monday to Friday:
> poker_vector <- c(140, -50, 20, -120, 240)
> roulette_vector <- c(-24, -50, 100, -350, 10)
> days_vector <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")
> names(poker_vector) <- days_vector
> names(roulette_vector) <- days_vector
> 
> # Define a new variable based on a selection
> roulette_selection_vector <- poker_vector[2:4]
> 
> # See result
> roulette_selection_vector
  Tuesday Wednesday  Thursday 
      -50        20      -120

Explanation

This line is important

# Define a new variable based on a selection roulette_selection_vector <- poker_vector[2:4]

How to learn from this program

First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.

Practice suggestion

After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.