R Code Style

This guide is based on:

• Google's R Style - https://google.github.io/styleguide/Rguide.xml
• R Packages book - http://r-pkgs.had.co.nz/r.html#style

Rules

1. File Names: end in .R and use _ if necessary
2. Variables: variable.name
3. Function Names: function_names
4. Constants: UPPERCASE
5. Line Length: maximum 80 characters
6. Indentation: two spaces, no tabs Spacing
7. Curly Braces: Always indent the code inside curly braces
8. if: It’s ok to leave very short statements on the same line without braces
9. else: Surround else with braces (and the if too)
10. for: Always with braces
11. Assignment: use <-, not =
12. Semicolons: don't use them
13. Space:

• Place spaces around all binary operators (=, +, -, <-, etc.)
• Spaces around ='s are optional when passing parameters in a function call or list name
• Do not place a space before a comma, but always place one after a comma
• Place a space before left parenthesis, except in a function call

14. Errors: Errors should be raised using stop()
15. Documentation: Omit the @title and @description

##Examples

IF

#Valid Examples
if (debug) do_something()

if (debug) {
  do_something()
}

if (debug) {
  do_something()
} 
else {
  do_nothing()
}

Functions

short_function <- function (a, b) {
  # Code
}

PredictCTR <- function(query, property, num.days,
                       show.plot = TRUE) {
  # Code
}

long_function_name <- function(a = "a long argument", 
                               b = "another argument",
                               c = "another long argument") {
  # Code
}

cat("one", "Two", "\n")

plot(x    = x.coord,
     y    = data.mat[, MakeColName(metric, ptiles[1], "roiOpt")],
     ylim = ylim,
     xlab = "dates",
     ylab = metric,
     main = (paste(metric, " for 3 samples ", sep = "")))

Braces

# Good Examples
diamonds[5, ]
total <- sum(x[, 1])
total <- sum(x[1, ])

Comments

# Load data ---------------------------

# Create histogram of frequency of campaigns by pct budget spent.
hist(df$pct.spent,
     breaks = "scott",  # method for choosing number of buckets
     main   = "Histogram: fraction budget spent by campaignid",
     xlab   = "Fraction of budget spent",
     ylab   = "Frequency (count of campaignids)")