Week 1: Your First Steps with R

Basic Syntax and Conventions: The Rules of R.

Like any language, R has its grammar and style. Understanding these basics is key to writing clear and functional R code.

• Comments: Explain your code using comments. In R, comments start with the hash symbol `#`. Everything after `#` on that line is ignored by R.

  # This is a comment explaining the code below
  radius <- 5 # Assigning the value 5 to the variable 'radius'

• Case Sensitivity: R is case-sensitive. `myVariable`, `MyVariable`, and `myvariable` are treated as distinct variables.
• Statements: R code is executed statement by statement, typically one per line. You can put multiple statements on one line separated by semicolons `;`, but this is generally less readable.

  a <- 1; b <- 2; print(a+b) # Less common style

• Assignment Operator: The preferred assignment operator in R is `<-`. While `=` also works for assignment in most contexts, `<-` is stylistically preferred and less ambiguous (as `=` is also used for function arguments).

  x <- 100   # Preferred style
  y = 200    # Also works, but less conventional

• Blocks and Braces `{}`: Unlike Python's reliance on indentation[cite: 10], R uses curly braces `{}` to group multiple statements into a block, often used with control flow structures (like `if`, `for`) and functions. Indentation is still crucial for readability but doesn't define the block structure syntactically.

  if (x > 50) {
    print("x is large")
    print("This is part of the if block")
  }

• Variable Naming Conventions:
  • Should be descriptive.
  • Can contain letters, numbers, dots (`.`), and underscores (`_`).
  • Must start with a letter or a dot (if starting with a dot, the second character cannot be a number).
  • Common styles include `snake_case` (e.g., `user_age`) or using dots (e.g., `user.age`). Consistency is key.
  • Avoid using names of built-in functions (e.g., `c`, `list`, `mean`).

Getting comfortable with these basic rules will make your R learning journey smoother.