The Design of Everyday R Functions
Jon Harmon, Atorus Research
“All artificial things are designed.”
1️⃣ Make functionality obvious
2️⃣ Forgive input
3️⃣ Describe mistake fixes
Make it obvious what functions do
Make it obvious what functions do
Make it obvious what functions do
Make it obvious what functions do
Make it obvious what functions do
Make it obvious what functions do
Make it obvious what functions do
1️⃣ Functions = verbs
2️⃣ Arguments = nouns
3️⃣ Defaults = standards / hints
Forgive “close enough” input
Forgive “close enough” input
Forgive “close enough” input
Forgive “close enough” input
Forgive “close enough” input
compile_order_df <- function(items, prices, tax_rate = 0.0825) {
prices <- stbl::to_dbl(prices)
tax_rate <- stbl::to_dbl_scalar(tax_rate)
items <- stbl::to_chr(items)
sales_tax <- ceiling(prices * tax_rate * 100) / 100
total_price <- prices + sales_tax
data.frame(
item = items,
price = prices,
sales_tax = sales_tax,
total_price = total_price
)
}Forgive “close enough” input
Forgive “close enough” input
compile_order_df <- function(items, prices, tax_rate = 0.0825) {
prices <- stbl::to_dbl(prices)
tax_rate <- stbl::to_dbl_scalar(tax_rate)
items <- stbl::to_chr(items)
sales_tax <- ceiling(prices * tax_rate * 100) / 100
total_price <- prices + sales_tax
data.frame(
item = items,
price = prices,
sales_tax = sales_tax,
total_price = total_price
)
}compile_order_df <- function(items, prices, tax_rate = 0.0825) {
prices <- as.double(prices)
tax_rate <- as.double(tax_rate)
items <- as.character(items)
sales_tax <- ceiling(prices * tax_rate * 100) / 100
total_price <- prices + sales_tax
data.frame(
item = items,
price = prices,
sales_tax = sales_tax,
total_price = total_price
)
}Tell users how to fix mistakes
Tell users how to fix mistakes
compile_order_df <- function(items, prices, tax_rate = 0.0825) {
prices <- stbl::to_dbl(prices)
tax_rate <- stbl::to_dbl_scalar(tax_rate)
items <- stbl::to_chr(items)
sales_tax <- ceiling(prices * tax_rate * 100) / 100
total_price <- prices + sales_tax
data.frame(
item = items,
price = prices,
sales_tax = sales_tax,
total_price = total_price
)
}Tell users how to fix mistakes
Tell users how to fix mistakes
Tell users how to fix mistakes
Error:
! `prices` <character> must be coercible to <double>
✖ Can't convert some values due to incompatible values.
• Locations: 2
• Values: "b"
ℹ Repair or remove these values and try again.❗ Problem statement
❌ Exact issue (if known)
🔵 More info
ℹ️ Suggestions