Introduction
Comparison operators
R has a set of operators that is the same as many other languages:
1 == 2 # FALSE
1 != 2 # TRUE
1 < 2 # TRUE
1 > 2 # FALSE
1 <= 2 # TRUE
1 >= 2 # FALSE
Branching
The basic form of an if-else is
if (x > 10) {
y <- "big"
} else if (x > 2) {
y <- "medium"
} else {
y <- "tiny"
}
In this case, parentheses () around the boolean and braces {} around the statement are both required.
A simple if statement can be shortened:
if (x == 0) return("success")
Instructions
In this exercise you'll be writing code to analyze the production of an assembly line in a car factory. The assembly line's speed can range from 0 (off) to 10 (maximum).
At its lowest speed (1), 221 cars are produced each hour. The production increases linearly with the speed. So with the speed set to 4, it should produce 4 * 221 = 884 cars per hour. However, higher speeds increase the likelihood that faulty cars are produced, which then have to be discarded.
You have three tasks.
1. Calculate the success rate
Implement the success_rate() method to calculate the ratio of an item being created without error for a given speed. The following table shows how speed influences the success rate:
-
0: 0% success rate.
-
1 to 4: 100% success rate.
-
5 to 8: 90% success rate.
-
9: 80% success rate.
-
10: 77% success rate.
success_rate(10)
# => 0.77
2. Calculate the production rate per hour
Implement the production_rate_per_hour() method to calculate the assembly line's production rate per hour, taking into account its success rate:
production_rate_per_hour(6)
# => 1193.4
Note that the value returned is a double.
3. Calculate the number of working items produced per minute
Implement the working_items_per_minute() method to calculate how many working cars are produced per minute:
working_items_per_minute(6)
# => 19
Note that the value returned is an integer: incomplete items are not included.
Learning Exercise
