best ruby cheat sheet
def greeting(hello, *names) # *name is a splat argument, takes several parameters passed in an array return "#{hello}, #{names}" end start = greeting("Hi", "Justin", "Maria", "Herbert") # call a method by name def name(variable=default) ### The last line in here get's returned by default end
best ruby cheat sheet
hash = { "key1" => "value1", "key2" => "value2" } # same as objects in JavaScript hash = { key1: "value1", key2: "value2" } # the same hash using symbols instead of strings my_hash = Hash.new # same as my_hash = {} – set a new key like so: pets["Stevie"] = "cat" pets["key1"] # value1 pets["Stevie"] # cat my_hash = Hash.new("default value") hash.select{ |key, value| value > 3 } # selects all keys in hash that have a value greater than 3 hash.each_key { |k| print k, " " } # ==> key1 key2 hash.each_value { |v| print v } # ==> value1value2 my_hash.each_value { |v| print v, " " } # ==> 1 2 3
best ruby cheat sheet
=begin Bla Multyline comment =end
best ruby cheat sheet
for i in 1..5 next if i % 2 == 0 # If the remainder of i / 2 is zero, we go to the next iteration of the loop. print i end
best ruby cheat sheet
unless false # unless checks if the statement is false (opposite to if). puts “I’m here” else puts “not here” end # or puts "not printed" unless true
best ruby cheat sheet
i = 0 loop do i += 1 print "I'm currently number #{i}” # a way to have ruby code in a string break if i > 5 end
best ruby cheat sheet
"Hello".length # 5 "Hello".reverse # “olleH” "Hello".upcase # “HELLO” "Hello".downcase # “hello” "hello".capitalize # “Hello” "Hello".include? "i" # equals to false because there is no i in Hello "Hello".gsub!(/e/, "o") # Hollo "1".to_i # transform string to integer –– 1 "test".to_sym # converts to :test "test".intern # :test :test.to_s # converts to "test"
best ruby cheat sheet
10.times do print “this text will appear 10 times” end
best ruby cheat sheet
i = 0 until i == 6 puts i i += 1 end
best ruby cheat sheet
my_array = [a,b,c,d,e] my_array[1] # b my_array[2..-1] # c , d , e multi_d = [[0,1],[0,1]] [1, 2, 3] << 4 # [1, 2, 3, 4] same as [1, 2, 3].push(4)
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