Ruby tips

tip.rb

# string merging
"asd" "qwe" "zxc"
# => "asdqwezxc"


# separators may be a space
% sometext .size
# => 8


# fast array creation
[*0..5]
# => [0, 1, 2, 3, 4, 5]


# json pretty print
require 'json'
a = {a: [1,2,3], b: 'c'}
j a
# => {"a":[1,2,3],"b":"c"}
jj a
# => 
# {
#   "a": [
#     1,
#     2,
#     3
#   ],
#   "b": "c"
# }


# underscore as a last result (irb)
"TEST".downcase
# => "test"
_
# => "test"
_ + _
# => "testtest"


# source path
require 'json'
method(:j).source_location
# => ["/Users/artemeff/.rbenv/versions/2.0.0-p0/lib/ruby/2.0.0/json/common.rb", 447]


# extract data to variables from regular expression 
str = "Fred Flinstone: TESTBANGAHAHA"
str[/(\w+) (\w+)/]
# => "Fred Flinstone"
str[/(\w+) (\w+)/, 1]
# => "Fred"
str[/(\w+) (\w+)/, 2]
# => "Flinstone"
str[/(?<first>\w+) (?<last>\w+)/, :last]
# => "Flinstone"
$~[:first]
# => "Fred"
$~
# => #<MatchData "Fred Flinstone" first:"Fred" last:"Flinstone">
/(?<first>\w+) (?<last>\w+)/ =~ str
first
# => "Fred"
last
# => "Flinstone"