Chapter8-Strings, Symbols and other scalar objects

Chapter8-Strings, Symbols and other scalar objects/string_manipulation.rb

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+### string manipulation
+
+>> string = "Ruby is a cool language"
+=> "Ruby is a cool language"
+
+---------------------------------------
+
+# if string is present then the slice
+# method will return the string else 
+# it will return nil.
+>> string.slice ("cool")
+=> "cool"
+
+>> sting.slice ("not cool")
+=> nil
+
+# there is another method slice! which
+# removes the characters from string
+# permanently.
+>> string.slice! ("cool")
+=> "cool"
+
+>> string
+>> "Ruby is a language"
+
+---------------------------------------
+
+# you can ask a string whether it
+# includes a given substring, using the 
+# includes? method.
+
+>> string.includes? ("Ruby")
+=> true
+
+# you can test for a given start or end
+# to a string with start_with? and
+# end_with? method.
+
+>> string.start_with? ("Ruby")
+=> true
+
+>> string.end_with? ("!!!")
+=> false
+
+---------------------------------------
+
+# formatting strings
+
+>> string.rjust (30)
+=> "       Ruby is a cool language"
+
+>> string.ljust (30)
+=> "Ruby is a cool language       "
+
+# you can also perform paddding 
+
+>> string.rjust(30, ".")
+=> ".......Ruby is a cool language"
+
+# or do something like 
+
+>> "the middle".center(25, "*")
+=> "*******the middle********"
+
+---------------------------------------
+
+# chop and chomp methods are both in the
+# business of removing characters from
+# the emd of the strings. The main
+# difference being that chop removes the 
+# last character unconditionally, whereas
+# chomp removes a target substring if it 
+# finds that sub-string at the end of line.
+# By default, chomp's target substring is
+# newline - \n
+
+>> "Ruby is a cool language".chop
+=> "Ruby is a cool languag"
+
+>> "Ruby is a cool language\n".chomp
+=> "Ruby is a cool language"
+
+>> "Ruby is a cool language".chomp('age')
+=> "Ruby is a cool langu"
+
+---------------------------------------