diff options
Diffstat (limited to 'ruby.html.markdown')
-rw-r--r-- | ruby.html.markdown | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/ruby.html.markdown b/ruby.html.markdown index d77672ab..8e5f924a 100644 --- a/ruby.html.markdown +++ b/ruby.html.markdown @@ -23,6 +23,15 @@ contributors: ```ruby # This is a comment +=begin +This is a multi-line comment. +The beginning line must start with "=begin" +and the ending line must start with "=end". + +You can do this, or start each line in +a multi-line comment with the # character. +=end + # In Ruby, (almost) everything is an object. # This includes numbers... 3.class #=> Integer @@ -172,6 +181,9 @@ array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5] # Arrays can contain different types of items. [1, 'hello', false] #=> [1, "hello", false] +# You might prefer %w instead of quotes +%w[foo bar baz] #=> ["foo", "bar", "baz"] + # Arrays can be indexed. # From the front... array[0] #=> 1 @@ -247,7 +259,7 @@ else 'else, also optional' end -# If a condition controls invokation of a single statement rather than a block of code +# If a condition controls invocation of a single statement rather than a block of code # you can use postfix-if notation warnings = ['Patronimic is missing', 'Address too short'] puts("Some warnings occurred:\n" + warnings.join("\n")) if !warnings.empty? @@ -315,6 +327,11 @@ puts doubled puts array #=> [1,2,3,4,5] +# another useful syntax is .map(&:method) +a = ["FOO", "BAR", "BAZ"] +a.map { |s| s.downcase } #=> ["foo", "bar", "baz"] +a.map(&:downcase) #=> ["foo", "bar", "baz"] + # Case construct grade = 'B' @@ -410,7 +427,7 @@ def guests(&block) end # The 'call' method on the Proc is similar to calling 'yield' when a block is -# present. The arguments passed to 'call' will be forwarded to the block as arugments. +# present. The arguments passed to 'call' will be forwarded to the block as arguments. guests { |n| "You have #{n} guests." } # => "You have 4 guests." @@ -421,6 +438,16 @@ def guests(*array) array.each { |guest| puts guest } end +# There is also the shorthand block syntax. It's most useful when you need +# to call a simple method on all array items. +upcased = ['Watch', 'these', 'words', 'get', 'upcased'].map(&:upcase) +puts upcased +#=> ["WATCH", "THESE", "WORDS", "GET", "UPCASED"] + +sum = [1, 2, 3, 4, 5].reduce(&:+) +puts sum +#=> 15 + # Destructuring # Ruby will automatically destructure arrays on assignment to multiple variables. @@ -643,4 +670,4 @@ Something.new.qux #=> "qux" - [Ruby from other languages](https://www.ruby-lang.org/en/documentation/ruby-from-other-languages/) - [Programming Ruby](http://www.amazon.com/Programming-Ruby-1-9-2-0-Programmers/dp/1937785491/) - An older [free edition](http://ruby-doc.com/docs/ProgrammingRuby/) is available online. - [Ruby Style Guide](https://github.com/bbatsov/ruby-style-guide) - A community-driven Ruby coding style guide. -- [Try Ruby](http://tryruby.org) - Learn the basic of Ruby programming language, interactive in the browser. +- [Try Ruby](https://try.ruby-lang.org/) - Learn the basic of Ruby programming language, interactive in the browser. |