B.1 No parentheses around arguments

When we call a method that has arguments, we put the arguments within parentheses (()) immediately next to the method name (with no space between the method name and the opening parenthesis):

"hello".gsub("l", "z")

# => "hezzo"

Ruby will allow you to, optionally, drop the parentheses around arguments:

"hello".gsub "l", "z"

# => "hezzo"

It’s important to remember not to mix these two by putting a space before parentheses!

# If you're going to use parens, don't also have a space

"hello".gsub ("l", "z") # bad

I like to include the parentheses around arguments because it makes it clear what’s what, especially when you are chaining multiple methods together. The only time that I drop the parentheses is if I am using trivial methods at the beginning of a line, like p or ap:

# Rather than

p("Hi there")

# I will usually do this instead:

p "Hi there"