Ruby Keywords Flashcards
BEGIN
run this block when the script starts. BEGIN { puts “hi” }
END
Run this block when the script is done. END { puts “hi” }
alias
Create another name for a function. alias x y
and
Logical and, but lower priority than &&. puts “hello” and “goodbye”
begin
Start a block, usually for exceptions. begin end
break
Break out of a loop right now. while true; break; end
case
Case conditional, like an if. case X; when Y; else; end
class
Define a new class. Class X; end
def
Define a new function. def X(); end
defined?
Is this class/function/etc. defined already? defined? Class == “constant”
do
Create a block that maybe takes a parameter. (0..5).each do |x| puts x end
else
Else conditional If X; else; end
elsif
Else if conditional if X; elsif Y; else; end
end
Ends block, functions, classes, everything.
ensure
Run this code whether an exception happens or not.
for
For loop syntax. The .each syntax is preferred in ruby. for X in Y; end
if
If conditional. if X; end
in
In part for-loops. for X in Y; end
module
Define a new module. module X; end
next
Skip to the next element of a .each iterator. (0..5).each { |y| next }
not
Logical not. But use ! instead. not true == false
or
Logical or. puts “hello” or “goodbye”
redo
rerun a code block exactly the sames
(0..5).each {|e| redo if e > 2 }
rescue
Run this code if an exception happens
begin rescue X; end
retry
In a rescue clause, says to try the block again.
(0..5).each { |e| retry if e < 2 }
return
Returns a value from a function. Mostly optional.
return X
self
The current object, class, or module defined? self == "self
super
The parent of this class
then
Can be used with if optionally
if true then puts “hi” end
undef
Remove a function definition from a class undef X
unless
Inverse of if
unless false then puts “not” end
until
Inverse of while, execute block as long as false.
until false; end
when
Part of case conditional
case X; when Y; else; end
while
While loop
while true; end
yield
Pause and transfer control to the code block
