snippets.rb

def readStdIn()
  input = []
	while line = gets
		input << line.chomp
	end
	return input
end

# 1.9
def readFile(name)
	File.read(name, :encoding => Encoding::UTF_8).encode.split("\n")
end

#1.8
def readFileOther(name)
	input = []
	File.open(name, "r") {|io|
		while line = io.gets
			input << line
		end
	}
	return input
end
#1.9.3
def writeFile(name, data)
	File.write(name, data.join("\n"))
end
#1.8
def writeFileOther(name, data)
	File.open(name, "w") {|io|
		data.each {|line| io.puts line}
	}
end

# string to array, array to string
a = "1,2,3".split(",") #[1,2,3]
b = a.join(":") #"1,2,3

# stirng to number
"2".to_i 
"2".to_f

# collection
list =[1,2,3,4,5]

# filter, map -> reject, map. And, ! is destory method.
list.reject{|e| e > 2}.map{|n| n * 2}
#with index
list.each_with_index{|e, i| p "index:#{i}, valur:#{e}"}

#ref to previous element
list.each_cons(2){|first, second| p "[#{first},#{second}]"} #{1,2], [2,3], [3,4], [4,5]
#grouping
list.each_slice(2).map{|e| e} #[[1,2], [3,4], [5]]

# sum, 
list.inject{|e,i| e * i} # 120
list.inject{|e,i| e + i} # 15

#uniqe (set)
[1,2,3,4,4,4,2].uniq #[1,2,3,4]

#regeqp 
# initial
r1 = %r([\d]{4})
r2 = /[A-Z]{3}/

#mathc
r1 === "1234" # true
r2 === "abc"  # false

#with case
res = case "ABC"
 when r1; "r1 hit"
 when r2; "r2 hit"
 else; "not hit"
end #r2 hit

# get match string
%r|([\d]{4})/([\d]{2})/([\d]{2})| =~ "today is 2012/01/02."
p $` # today is 
p $& # 2012/01/02
p $1 # 2012
p $2 # 01
p $3 # 02
p $' # .