VIP برنامه نویسی Client Side

[☾♔TALAYEH_A♔☽]

Collections
ایجاد و استفاده از یک آرایه:

a = [1, 'hi', 3.14, 1, 2, [4, 5]]

a[2] # 3.14
a.reverse # [[4, 5], 2, 1, 3.14, 'hi', 1]
a.flatten.uniq # [1, 'hi', 3.14, 2, 4, 5]

 

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ایجاد و استفاده از یک هش:

hash = {:water => 'wet', :fire => 'hot'}
puts hash[:fire] # Prints: hot

hash.each_pair do |key, value| # Or: hash.each do |key, value|
puts "#{key} is #{value}"
end

# Prints: water is wet
# fire is hot

hash.delete_if {|key, value| key == water} # Deletes :water => 'wet'

 

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Blocks and iterators
هر دو سینتکس برای ایجاد یک بلوک کد:

{ puts "Hello, World!" }

== do puts "Hello, World!" end ==

 

[☾♔TALAYEH_A♔☽]

ارسال پارامتر به یک بلاک تا یک closure شود:

# In an object instance variable, remember a block.
def remember(&b)
@block = b
end

# Invoke the above method, giving it a block that takes a name.
remember {|name| puts "Hello, #{name}!"}

# When the time is right (for the object) -- call the closure!
@block.call("John")
# Prints "Hello, John!"

 

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بازگشت closure از یک متد:

def foo(initial_value=0)
var = initial_value
return Proc.new {|x| var = x}, Proc.new { var }
end

setter, getter = foo
setter.call(21)
getter.call # => 21

 

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دادن جریان کنترل یک برنامه به یک بلوک که در هنگام فراخوانی ایجاد شده:

def a
yield "hello"
end

# Invoke the above method, passing it a block.
a {|s| puts s} # Prints: 'hello'

# Perhaps the following needs cleaning up.

# Breadth-first search
def bfs(e) # 'e' should be a block.
q = [] # Make an array.
e.mark # 'mark' is a user-defined method. (??)
yield e # Yield to the block.
q.push e # Add the block to the array.
while not q.empty? # This could be made much more Ruby-like.
u = q.shift
u.edge_iterator do |v|
if not v.marked? # 'marked?' is a user-defined method.
v.mark
yield v
q.push v
end
end
end
end
bfs(e) {|v| puts v}

 

[☾♔TALAYEH_A♔☽]

ایجاد حلقه بر روی آرایه‌ها و enumorationها با استفاده از بلوکها:

a = [1, 'hi', 3.14]
a.each {|item| puts item} # Prints each element
(3..6).each {|num| puts num} # Prints the numbers 3 through 6
[1,3,5].inject(0) {|sum, element| sum + element} # Prints 9 (you can pass both a parameter and a block)

 

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بلوکها با بسیاری از متدهای داخلی روبی کار می‌کنند:

File.open('file.txt', 'w+b') do |file|
file.puts 'Wrote some text.'
end # File is automatically closed here

 

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یا:

File.readlines('file.txt').each do |line|
# Process each line, here.
end

 

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استفاده از یک enumoration و یک بلوک برای جذر گرفتن اعداد ۱ تا ۱۰:

(1..10).collect {|x| x*x} => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]