Learning ruby - day 1

Table of Contents
  • Introduction
  • Content
  • Conclusion
    • Introduction
    Hey guys, welcome to my blog recording my ruby self-taught process
    I decided to learn this amazing language while I was trying to solving some ruby challenges to get my tenth badge in HackerRank
    Ok let's do it
    Create my first program in ruby 
    print "Hello World!!!"
    Output
    PS D:\Workplace> ruby hello-world.rb
Hello World!!!

    print "\n" equals puts

    print "First line "
print "still first line\n"
puts "Second line"
puts "Thirld line"
    Output
    First line still first line
Second line
Thirld line
    Everything is object 
    print else
    Output
    main
    Call Object Method

    check whether the num is even or odd

    num = 2
print num.even?
    Output
    true
    Call Object Method Parameters

    print the quotient of num and 2

    num = 2
num.div 2
print num
    Output
    1
    First loop

    print the value of each member in array to the power of 2

    array = [1, 2, 3, 4, 5]
array.each do |num|
    puts num.pow 2
end
    Output
    1
4
9
16
25
    First function

    print ASCII chars of any decimal number in array if number is not odd

    def print_char(array)
    array.each do |num|
        puts num.chr unless num.odd?
    end
end
array = [65, 66, 67, 68, 69, 70, 71]
print_char(array)
    Output
    B
D
F
    Array
    Working on single element

    Delete last element

    arr.pop

    Delete first element

    arr.shift

    Delete element at position a given position

    arr.delete_at(2)
    Working on multiple elements

    Delete all occurrences of a given element

    arr.delete(5)

    Delete elements if

    arr.delete_if {|a| a < 2}

    Delete elements unless

    arr.keep_if {|a| a < 4}
    Create subarray

    Select elements from array to subarray

    arr2 = arr.select {|a| a > 2}
print arr2

    Reject elements from array to subarray

    arr2 = arr.reject {|a| a > 2}

    Reject elements from array till returns false for the first time

    arr2 = arr.drop_while {|a| a > 1}
    Hash, a dictionary-like data structures 
    # initialize and set default value
empty_hash = Hash.new 
empty_hash.default = 1
# or
default_hash = Hash.new(1)
    Set value
    new_hash = {"key1" => 12, "key2" => 50}
# or
new_hash = Hash.new
new_hash["key1"] = 12
new_hash["key2"] = 50
# or
new_hash.store("key1", 12)
new_hash.store(1512032, 50)
    Loop with hash
    hash.each do |key, value|
    puts key
    puts value
end
# or
hash.each do |array|
    # now key is array[0], value is array[1]
    puts array[0]
    puts array[1]
end
    Delete pair
    # Delete specific key
hash.delete("key1")
# Delete if
hash.keep_if {|key, value| key.is_a? Integer} 
# or 
hash.delete_if {|key, value|key.even? }
    Infinite Loop 
    i = 0
loop do
    puts i
    i += 1
    break if i == 10
end
    Output
    1
2
3
4
5
6
7
8
9
10
    Conclusion
    We have learned how to print output
    How to do some basic loop and function
    Learned some common methods of array and a dictionary-like data structures called hash
    I'd like to thank HackerRank for giving me a chance to acknowledge and be interesting in this cool language
    If guys found Ruby is fascinating, please come to the link below and solve some Ruby challenges with me
    If you have any question or suggestion, please let me know at the comment section below.
    OK I'm going to wrap this up here
    Thanks for reading my blog

    33

    Categories:

    Ruby

    Tags:

    RubyBeginnersRubyday1Aderayevans

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    Learning ruby - day 1