R 데이터 초보 / 벡터의 연산(덧셈, 뺄셈) _ Introduction to R by EDX

벡터의 연산 Vector Arithmetic 의 기본은 간단하다. 

기존의 덧셈, 뺄셈기호를 이용하여 계산할 수 있다. 아래에 다양한 연습문제를 통해 익혀보았다. 

 

Summing and subtracting vectors

Take the element-wise sum of the variables A_vector and B_vector and it assign to total_vector. The result should be a vector. Inspect the result by printing total_vector to the console. Do the same thing, but this time subtract B_vector from A_vector and assign the result to diff_vector. Finally, print diff_vector to the console as well.

# A_vector and B_vector have already been defined for you

A_vector <- c(1, 2, 3)

B_vector <- c(4, 5, 6)

# Take the sum of A_vector and B_vector: total_vector

total_vector <- A_vector + B_vector

# Print total_vector

total_vector

# Calculate the difference between A_vector and B_vector: diff_vector

diff_vector <- A_vector - B_vector

# Print diff_vector

diff_vector

 

 

Calculate your earnings

Assign to the variable total_daily how much you won or lost on each day in total (poker and roulette combined).

# Casino 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

# Calculate your daily earnings: total_daily

total_daily <- poker_vector + roulette_vector

 

 

Calculate total winnings : sum()

Calculate the total amount of money that you have won/lost with poker and assign it to the variable total_poker. Do the same thing for roulette and assign the result to total_roulette. Now that you have the totals for roulette and poker, you can easily calculate total_week (which is the sum of all gains and losses of the week). Print the variable total_week.

# Casino 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

# Total winnings with poker: total_poker

total_poker <- sum(poker_vector)

# Total winnings with roulette: total_roulette

total_roulette <- sum(roulette_vector)

# Total winnings overall: total_week

total_week <- total_poker + total_roulette

# Print total_week

total_week

 

 

Comparing total winnings

Create a new vector containing logicals, poker_better, that tells whether your poker gains exceeded your roulette results on a daily basis. Calculate total_poker and total_roulette as in the previous exercise. Using total_poker and total_roulette, Check if your total gains in poker are higher than for roulette by using a comparison. Assign the result of this comparison to the variable choose_poker and print it out. What do you conclude, should you focus on roulette or on poker?

# Casino 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

# Calculate poker_better

poker_better <- as.logical(poker_vector > roulette_vector)

# Calculate total_poker and total_roulette, as before

total_poker <- sum(poker_vector)

total_roulette <- sum(roulette_vector)

# Calculate choose_poker

choose_poker <- total_poker > total_roulette

# Print choose_poker

choose_poker

 

 

First steps in rational gambling

Use the sum() function twice in combination with the + operator to calculate the total gains for your entire past week in Vegas (this means for both poker and roulette). Assign the result to total_past. Calculate difference of past to present poker performance: Using the - operator, subtract poker_past from poker_present, to calculate diff_poker. diff_poker should be a vector with 5 elements.

# Calculate total gains for your entire past week: total_past

total_past <- sum(poker_past + roulette_past)

# Difference of past to present performance: diff_poker

diff_poker <- poker_present - poker_past