First, some motivation. Here are two equivalent blocks of code:

ggplot(filter(summarize(group_by(flights,origin,carrier),n=n(),ave_delay=mean(dep_delay,rn.rm=T)),n>1000))+geom_point()

Which you would have recognized written like this:

flights %>%
  group_by(origin, carrier) %>%
  summarize(n         = n(),
            ave_delay = mean(dep_delay, na.rm = TRUE)) %>%
  filter(n > 1000) %>%
  ggplot(aes(n, ave_delay, color = carrier)) + geom_point()

One is pretty easy to read, the other is horrendous. The two style guides you should use in your R code are:

• Google’s
• Hadley Wickham’s.

Use meaningful and consistent names

• Dots: variable.name (Google preferred)
• Camel case: variableName (Google accepted)
• Capitalized: VariableName (Google accepted)
• Underscore: variable_name (Tidyverse)

In choosing names, be sure that the names you choose have meaning.

Bad:

one <- c(1, 2, 3, 4)
two <- mean(one)
other <- c("one", "two", "three", "four")

Good:

lengths     <- c(1, 2, 3, 4)
mean_length <- mean(lengths)
obs_names   <- c("one", "two", "three", "four")

Use white space!

R doesn’t care about spaces or newlines in your code. Use this to write beautiful code!

Compare:

z<-my_func(10,c(1,2,3,4),"string",TRUE,mean(x)>20,long=mad(x))

To:

z <- my_func(a    = 10,
             b    = c(1,2,3,4),
             c    = "string",
             d    = TRUE,
             e    = mean(x) > 20,
             long = mad(x))

Note the use of:

• Named arguments when you’ve got more than 2 - 3 arguments
• White space around all operators (“=”, “>”, etc.)
• New lines to enhance readability; keep each line < 80 characters
• White space to line up “=”

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