/ruby/string_examples.yml

--- 
ruby_string_examples: |-
  # Use single quotes \' to create a literal string. 
    # Inside a quoted string #{foobar}, \, ... is not interpreted.
    %q = single quoted 
    # e.g. 
    %q{ 'single quoted text' doesn't need to be escaped} =>  " 'single quoted text' doesn't need to be escaped" 
  
    %Q = double quoted
    # e.g. %Q{ "doublee quoted text" doesn't need to be escaped}
  
    # Can replace curly braces with any other character, like a dot "."
    %q = single quoted
    # e.g.
    %q. 'single quoted text' doesn't need to be escaped. =>  " 'single quoted text' doesn't need to be escaped" 
  
    # here document
    mystring = <<EOS
    this is a 
    mulitword 
    string
    EOS
    
    # Most operations don't change the orginal string.
    # Unless the bang \! is used or the method implies it, replace method.
  
    "a" + "b" => "ab"
    "a" << "b"  => "ab"
    b = "some string"
    "a#{b}" =>  "asome string" 
    "%d some text more text" % 33 => "33 some text more text" 
    "%d some text more text" % [55]  => "55 some text more text" 
    "some int %d some float %f" % [55, 44.7] =>  "some int %d some float %f" % [55, 44.7]
    # Massaging strings
    # Default will create a new string. For in-place changes add bang ! to method name
  
    capitilize	"tom".captilize => "Tom"
    upcase	"tom".upcase => "TOM"
    downcase	"TOM".downcase => "tom"
    swapcase	"tom".swapcase = "TOM"
    strip		 "  lose the outer spaces  ".strip => "lose the outer spaces"
    rstrip	 "  lose the right spaces   ".rstrip =>  "  lose the outer spaces" 
    lstrip	 " lose the left spaces    ".lstrip =>  "lose the outer spaces  " 
    chop		 "remove the last character".chop => "remove the last characte"
    chomp		 "remove trailing newline\n".chomp =>  "remove the the trailing newline" 
    reverse	 " gnirts eht esrever".reverse => "reverse the string"
  
    # Getting character
    "foobar"[3] => 98 # ascii number for 'b'
    "foobar"[3].chr => "b" 
    "foobar"[3,2] => "ba"
    "foobar"[-2].chr => "a"
  
    # Getting Substrings
    "This is a string"[5, 4] => "is a"
    "foo bar baz"[/foo (\w+) baz/, 1]  => "bar"
  
  
    # Replacement
    foo = "bar"
    foo.replace "hush" => "hush"
    foo = "This is a string"
    foo[5, 4] => "is a"
    "Some string with  whitespace\n and\t\tlines".gsub(/\s+/,'_') => "Some_string_with_whitespace_and_lines" 
    
    # Equality
    "a" == "a" => true
    # they are not the place in memory. different obj ids
    "a".equal? "a" =>  false
  
    # Comparision
    <=> spaceship operator, return -1, 0, 1 for less than, equal to, greater than