Slide 1
Slide 1 text
No content
Slide 2
Slide 2 text
No content
Slide 3
Slide 3 text
No content
Slide 4
Slide 4 text
No content
Slide 5
Slide 5 text
No content
Slide 6
Slide 6 text
for ($i=0; $i<3; $i++) {
echo "hello";
}
Slide 7
Slide 7 text
for ($i=0; $i < $array.length; $i++) {
echo $array[$i];
}
Slide 8
Slide 8 text
$result = [];
for ($i=0; $i<$array.length; $i++) {
if ($array[$i] % 2 == 0) {
$result[] = $array[$i];
}
}
return $result;
Slide 9
Slide 9 text
No content
Slide 10
Slide 10 text
3.times do
puts "hello"
end
Slide 11
Slide 11 text
array.each do |item|
puts item
end
Slide 12
Slide 12 text
array.select do |n|
n.even?
end
Slide 13
Slide 13 text
No content
Slide 14
Slide 14 text
No content
Slide 15
Slide 15 text
No content
Slide 16
Slide 16 text
No content
Slide 17
Slide 17 text
No content
Slide 18
Slide 18 text
No content
Slide 19
Slide 19 text
(5..7).each do |n|
puts n
end
# 5
# 6
# 7
Slide 20
Slide 20 text
No content
Slide 21
Slide 21 text
march = Date.new(2022, 3)
sept = Date.new(2022, 9)
(march..sept).each do |date|
# ...
end
# March 1, March 2, March 3, ...
Slide 22
Slide 22 text
(march..sept).select do |date|
date.day == 1
end.each do |date|
# ...
end
# March 1, April 1, May 1, ...
Slide 23
Slide 23 text
No content
Slide 24
Slide 24 text
No content
Slide 25
Slide 25 text
class Month
def initialize(months)
@months = months
end
end
Slide 26
Slide 26 text
class Month
def self.from_parts(year, months)
new (year * 12) + months
end
end
Slide 27
Slide 27 text
march = Month.from_parts(2022, 3)
sept = Month.from_parts(2022, 9)
(march..sept).each do |month|
# ...
end
# ArgumentError: bad value for range
Slide 28
Slide 28 text
No content
Slide 29
Slide 29 text
No content
Slide 30
Slide 30 text
No content
Slide 31
Slide 31 text
class Month
def <=>(other)
months <=> other.months
end
end
Slide 32
Slide 32 text
class Month
def succ
Month.new(months.succ)
end
end
Slide 33
Slide 33 text
march = Month.from_parts(2022, 3)
sept = Month.from_parts(2022, 9)
(march..sept).each do |month|
# ...
end
# March 2022, April 2022, May 2022, ...
Slide 34
Slide 34 text
No content
Slide 35
Slide 35 text
No content
Slide 36
Slide 36 text
No content
Slide 37
Slide 37 text
No content
Slide 38
Slide 38 text
No content
Slide 39
Slide 39 text
No content
Slide 40
Slide 40 text
No content
Slide 41
Slide 41 text
No content
Slide 42
Slide 42 text
No content
Slide 43
Slide 43 text
No content
Slide 44
Slide 44 text
class CompositeFile
def initialize(files)
@files = files
end
end
Slide 45
Slide 45 text
monte_cristo = CompositeFile.new(chapters)
monte_cristo.find { |line| line.include? "Villefort" }
# Undefined method `find` for CompositeFile
Slide 46
Slide 46 text
No content
Slide 47
Slide 47 text
No content
Slide 48
Slide 48 text
def each
@files.each do |file|
file.each do |line|
yield line
end
end
end
Slide 49
Slide 49 text
monte_cristo.each do |line|
puts line
end
Slide 50
Slide 50 text
No content
Slide 51
Slide 51 text
class CompositeFile
include Enumerable
# ...
end
Slide 52
Slide 52 text
monte_cristo.find do |line|
line.include? "Villefort"
end
# => "“Could you ever have credited such a thing, my dear
Danglars?” asked M. Morrel, as, on his return to the port
for the purpose of gleaning fresh tidings of Dantès, from
M. de Villefort, the assistant procureur, he overtook his
supercargo and Caderousse."
Slide 53
Slide 53 text
No content
Slide 54
Slide 54 text
No content
Slide 55
Slide 55 text
No content
Slide 56
Slide 56 text
array.each_with_index(1) do |item, index|
puts "#{index}. #{item}"
end
Slide 57
Slide 57 text
No content
Slide 58
Slide 58 text
array.map.with_index(1) do |item, index|
"#{index}. #{item}"
end
# => ["1. first", "2. second", ... ]
Slide 59
Slide 59 text
array = [1, 2, 3]
array.cycle(3).with_index(1).select do |item, index|
index.even? && item.even?
end
# => [[2, 2], [2, 8]]
Slide 60
Slide 60 text
No content
Slide 61
Slide 61 text
[1, 2, 3].map
# => #
Slide 62
Slide 62 text
No content
Slide 63
Slide 63 text
No content
Slide 64
Slide 64 text
3.times
#=> #
5.upto(10)
#=> #
[1, 2, 3].each
#=> #
Slide 65
Slide 65 text
No content
Slide 66
Slide 66 text
No content
Slide 67
Slide 67 text
No content
Slide 68
Slide 68 text
No content
Slide 69
Slide 69 text
enum = [1, 2].to_enum(:each)
enum.next
# => 1
enum.next
# 2
enum.next
# raise StopIteration
Slide 70
Slide 70 text
No content
Slide 71
Slide 71 text
percentages = Enumerator.produce { rand(100) }
percentages.next
# => 7
percentages.next
# => 51
Slide 72
Slide 72 text
No content
Slide 73
Slide 73 text
No content
Slide 74
Slide 74 text
numbers = [1, 2, 3].cycle
numbers.take(4)
# => [1, 2, 3, 1]
Slide 75
Slide 75 text
No content
Slide 76
Slide 76 text
No content
Slide 77
Slide 77 text
class CompositeBook
include Enumerable
def each
# by line
end
def each
# by word
end
end
Slide 78
Slide 78 text
class CompositeBook
def each_line
# ...
end
def each_word
# ...
end
end
Slide 79
Slide 79 text
class CompositeBook
def each_line
return to_enum(:each_line) unless block_given
# actual looping
end
end
Slide 80
Slide 80 text
monte_cristo.each_line.find { |line| ... }
monte_cristo.each_word.map { |word| ... }
Slide 81
Slide 81 text
No content
Slide 82
Slide 82 text
No content
Slide 83
Slide 83 text
No content