| instance methods | 
| % | str % arg
        -> aString | 
 | Format---Uses str as a format
      specification, and returns the result of applying it to
      arg. If the format specification contains more than one
      substitution, then arg must be an Arraycontaining the
      values to be substituted. SeeKernel::sprintfon page 427 for details of the format string.
  | "%05d" % 123 | » | "00123" |  
  | "%-5s: %08x" % [ "ID", self.id ] | » | "ID![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) : ![[visible space]](visible_space.gif) 200cd648" |  | | * | str * anInteger
        -> aString | 
 | Copy---Returns a new Stringcontaining anInteger copies of
      the receiver.
  | "Ho! " * 3 | » | "Ho! Ho! Ho! " |  | | + | str + aString
        -> aNewString | 
 | Concatenation---Returns a new Stringcontaining 
      aString concatenated to str.
  | "Hello from " + self.to_s | » | "Hello from main" |  | | << | str << aFixnum -> str str << anObject -> str
 | 
 | Append---Concatenates the given object to str. If the object is a Fixnumbetween 0 and 255, it is converted to a character
      before concatenation.
| a = "hello " |  
  | a << "world" | » | "hello world" |  
  | a << 33 | » | "hello world!" |  
  | a | » | "hello world!" |  | | <=> | str <=> aString
        -> -1, 0, +1 | 
 | Comparison---Returns -1 if str is less than, 0
      if str is equal to, and +1 if str is greater than
      aString. If the strings are of different lengths, and the
      strings are equal when compared up to the shortest length, then
      the longer string is considered greater than the shorter one. If
      the variable $=isfalse, the comparison is based
      on comparing the binary values of each character in the string.
      If$=is notfalse, then the comparison is
      case insensitive.[The locale is ignored when
        case-insensitive comparisons are performed, so ``\"o'' will not
        match ``\"O''.]<=>is the basis for the methods<,<=,>,>=, andbetween?,
      included from moduleComparable. The methodString#==does not useComparable#==.
  | "abcdef" <=> "abcde" | » | 1 |  
  | "abcdef" <=> "abcdef" | » | 0 |  
  | "abcdef" <=> "abcdefg" | » | -1 |  
  | "abcdef" <=> "ABCDEF" | » | 1 |  
| $= = true |  
  | "abcdef" <=> "ABCDEF" | » | 0 |  | | == | str == anObject
        -> trueorfalse | 
 | Equality---If anObject is not a String, returnsfalse. Otherwise, returnstrueif str<=>anObject returns zero. | | === | str === anObject
        -> trueorfalse | 
 | Case Equality---Synonym for String#==. | | =~ | str =~ anObject
        -> aFixnum or nil | 
 | Match---If anObject is a Regexpor aString, uses it as a
      pattern to match against str.  Returns
      the position the match starts, ornilif there is no match.
      Otherwise, invokes
      anObject.=~, passing str as an argument. The
      default=~inObjectreturnsfalse.
  | "cat o' 9 tails" =~ "\\d" | » | 7 |  
  | "cat o' 9 tails" =~ /\d/ | » | 7 |  
  | "cat o' 9 tails" =~ 9 | » | false |  | | [ ] | str[ aFixnum ] -> aFixnum or nilstr[ aFixnum, aFixnum ] -> aString or
 nilstr[ aRange ] -> aString or
 nilstr[ aRegexp ] -> aString or
 nilstr[ aString ] -> aString or
 nil | 
 | Element Reference---If passed a single Fixnum, returns the
        code of the character at that position. If passed twoFixnumobjects, returns a substring starting at the offset given
        by the first, and a length given by the second. If given a
        range, a substring containing characters at offsets given by
        the range is returned. In all three cases, if an offset is
        negative, it is counted from the end of str. Returnsnilif the initial offset falls outside the string, the length is
        negative, or the beginning of the range is greater than the
        end.
      If aRegexpis supplied, the matching portion of str is
      returned. If aStringis given, that string is returned if it 
      occurs in str. In both cases,nilis returned if there
      is no match.
| a = "hello there" |  
  | a[1] | » | 101 |  
  | a[1,3] | » | "ell" |  
  | a[1..3] | » | "ell" |  
  | a[-3,2] | » | "er" |  
  | a[-4..-2] | » | "her" |  
  | a[-2..-4] | » | nil |  
  | a[/th[aeiou]/] | » | "the" |  
  | a["lo"] | » | "lo" |  
  | a["bye"] | » | nil |  | | [ ]= | str[ aFixnum ] = aFixnum str[ aFixnum ] = aString
 str[ aFixnum, aFixnum ] = aString
 str[ aRange ] = aString
 str[ aRegexp ] = aString
 str[ aString ] = aString
 | 
 | Element Assignment---Replaces some or all of the content of
        str. The portion of the string affected is determined using
        the same criteria as String#[]. If the replacement
        string is not the same length as the text it is replacing, the
        string will be adjusted accordingly.  
                The forms that take aFixnumwill raise anIndexErrorif the value is out of range; theRangeform will raise aRangeError, and theRegexpandStringforms will silently ignore the assignment.
  | a = "hello"; a[2]       = 96;    a | » | "he`lo" |  
  | a = "hello"; a[2, 4]    = "xyz"; a | » | "hexyz" |  
  | a = "hello"; a[-4, 2]   = "xyz"; a | » | "hxyzlo" |  
  | a = "hello"; a[2..4]    = "xyz"; a | » | "hexyz" |  
  | a = "hello"; a[-4..-2]  = "xyz"; a | » | "hxyzo" |  
  | a = "hello"; a[/[el]+/] = "xyz"; a | » | "hxyzo" |  
  | a = "hello"; a["l"]     = "xyz"; a | » | "hexyzlo" |  
  | a = "hello"; a["ll"]    = "xyz"; a | » | "hexyzo" |  
  | a = "hello"; a["bad"]   = "xyz"; a | » | "hello" |  
  | a = "hello"; a[2, 0]    = "xyz"; a | » | "hexyzllo" |  | | ~ | ~str
        -> aFixnum or nil | 
 | Equivalent to $_ =~ str. | | capitalize | str.capitalize
        -> aString | 
 | Returns a copy of str with the first character converted to
      uppercase and the remainder to lowercase. 
  | "hello".capitalize | » | "Hello" |  
  | "HELLO".capitalize | » | "Hello" |  
  | "123ABC".capitalize | » | "123abc" |  | | capitalize! | str.capitalize!
        -> str or nil | 
 | Modifies str by converting  the first character to
      uppercase and the remainder to lowercase. Returns nilif 
      no changes are made.
| a = "hello" |  
  | a.capitalize! | » | "Hello" |  
  | a | » | "Hello" |  
  | a.capitalize! | » | nil |  | | center | str.center( anInteger )
        -> aString | 
 | If anInteger is greater than the length of str, returns a
      new Stringof length anInteger with str centered
      between spaces; otherwise,
      returns str.
  | "hello".center(4) | » | "hello" |  
  | "hello".center(20) | » | "![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) hello ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) " |  | | chomp | str.chomp( aString= $/)
        -> aString | 
 | Returns a new Stringwith the given record separator removed 
      from the end of str (if present).
  | "hello".chomp | » | "hello" |  
  | "hello\n".chomp | » | "hello" |  
  | "hello \n there".chomp | » | "hello \n there" |  
  | "hello".chomp("llo") | » | "he" |  | | chomp! | str.chomp!( aString= $/)
        -> str ornil | 
 | Modifies str in place as described for String#chomp,
      returning str, ornilif no modifications were made. | | chop | str.chop
        -> aString | 
 | Returns a new Stringwith the last character removed. If the 
      string ends with\r\n, both characters are
      removed. Applyingchopto an empty string returns an
      empty string.String#chompis often a safer alternative,
      as it leaves the string unchanged  if it doesn't end in a record 
      separator.
  | "string\r\n".chop | » | "string" |  
  | "string\n\r".chop | » | "string\n" |  
  | "string\n".chop | » | "string" |  
  | "string".chop | » | "strin" |  
  | "x".chop.chop | » | "" |  | | chop! | str.chop!
        -> str or nil | 
 | Processes str as for String#chop, returning str,
      ornilif str is the empty string.  See alsoString#chomp!. | | concat | str.concat( aFixnum ) -> str str.concat( anObject ) -> str
 | 
 | Synonym for String#<<. | | count | str.count( [aString]+ )
        -> aFixnum | 
 | Each aString parameter defines a set of characters to
      count. The intersection of these sets defines the characters to count
      in str. Any aString that starts with a caret (^) is
      negated. The sequence c1--c2 means all characters between
      c1 and c2. 
| a = "hello world" |  
  | a.count "lo" | » | 5 |  
  | a.count "lo", "o" | » | 2 |  
  | a.count "hello", "^l" | » | 4 |  
  | a.count "ej-m" | » | 4 |  | | crypt | str.crypt( aString )
        -> aString | 
 | Applies a one-way      
      cryptographic hash to str by invoking the standard library
      function crypt. The argument is the salt
      string, which should be two characters long, each character
      drawn from[a-zA-Z0-9./]. | | delete | str.delete( [aString]+ )
        -> aString | 
 | Returns a copy of str with all characters in the intersection of
      its arguments deleted. Uses the same rules for building the set
      of characters as String#count.
  | "hello".delete "l","lo" | » | "heo" |  
  | "hello".delete "lo" | » | "he" |  
  | "hello".delete "aeiou", "^e" | » | "hell" |  
  | "hello".delete "ej-m" | » | "ho" |  | | delete! | str.delete!( [aString]+ )
        -> str or nil | 
 | Performs a deleteoperation in place, returning str, ornilif str was not modified. | | downcase | str.downcase -> aString | 
 | Returns a copy of str with all uppercase letters replaced
      with their lowercase counterparts. The operation is locale
      insensitive---only characters ``A'' to ``Z'' are affected. 
  | "hEllO".downcase | » | "hello" |  | | downcase! | str.downcase!
        -> str or nil | 
 | Downcases the contents of str, returning nilif no
      changes were made. | | dump | str.dump -> aString | 
 | Produces a version of str with all nonprinting characters
      replaced by \nnnnotation and all special characters
      escaped. | | each | str.each( aString= $/)
        {| substr | block }
 -> str | 
 | Splits str using the supplied parameter as the record
      separator ( $/by default), passing each substring in turn 
      to the supplied block. If a zero-length record separator is
      supplied, the string is split on\ncharacters, except
      that multiple successive newlines are appended together.produces:| 
print "Example one\n"
"hello\nworld".each {|s| p s}
print "Example two\n"
"hello\nworld".each('l') {|s| p s}
print "Example three\n"
"hello\n\n\nworld".each('') {|s| p s}
 | 
 | 
Example one
"hello\n"
"world"
Example two
"hel"
"l"
"o\nworl"
"d"
Example three
"hello\n\n\n"
"world"
 | 
 | | each_byte | str.each_byte {| aFixnum | block }
        -> str | 
 | Passes each byte in str to the given block. produces:| 
"hello".each_byte {|c| print c, ' ' }
 | 
 | | each_line | str.each_line( aString= $/)
        {| substr | block }
 -> str | 
 | Synonym for String#each. | | empty? | str.empty? -> trueorfalse | 
 | Returns trueif str has a length of zero.
  | "hello".empty? | » | false |  
  | "".empty? | » | true |  | | gsub | str.gsub( pattern, replacement )
          -> aString str.gsub( pattern ) {| match | block }
          -> aString
 | 
 | Returns a copy of str with all occurrences of
      pattern replaced with either replacement or the
      value of the block. If a string is used as the replacement,
      special variables from the match (such as $&and$1) cannot be substituted into it, as substitution into
      the string occurs before the pattern match starts. However, the
      sequences\1,\2, and so on may be used to
      interpolate successive groups in the match. These sequences are shown in
      Table 22.7 on page 376.In the block form, the current match is passed in as a
      parameter, and variables such as| Backslash sequences in substitution
          strings 
  | Sequence | Text That Is Substituted |  
  | \1, \2, ... \9 | The value matched by the
          nth grouped subexpression |  
  | \& | The last match |  
  | \` | The part of the string before the match |  
  | \' | The part of the string after the match |  
  | \+ | The highest-numbered group matched |  |  |  | 
 $1,$2,$`,$&, and$'will be set
      appropriately. The value returned by the block will be
      substituted for the match on each call.
      The result inherits any tainting in the original string or any
      supplied replacement string.
  | "hello".gsub(/[aeiou]/, '*') | » | "h*ll*" |  
  | "hello".gsub(/([aeiou])/, '<\1>') | » | "h<e>ll<o>" |  
  | "hello".gsub('.') {|s| s[0].to_s + ' '} | » | "104 101 108 108 111 " |  | | gsub! | str.gsub!( pattern, replacement )
          -> str or nilstr.gsub!( pattern ) {| match | block }
          -> str or
 nil | 
 | Performs the substitutions of String#gsubin place,
      returning str, ornilif no substitutions were
      performed. | | hash | str.hash -> aFixnum | 
 | Generates a Fixnumhash value for str. If$=istrue, the hash will be case insensitive.
| $= = true |  
| hash = { 'cat' => 'Feline', 'dog' => 'canine' } |  
  | hash['cat'] | » | "Feline" |  
  | hash['cAt'] | » | "Feline" |  
| $= = false |  
  | hash.rehash     # re-calculate hash values | » | {"dog"=>"canine", "cat"=>"Feline"} |  
  | hash['cat'] | » | "Feline" |  
  | hash['cAt'] | » | nil |  | | hex | str.hex -> anInteger | 
 | Treats leading characters from str as a string of hexadecimal
      digits (with an optional sign and an optional 0x) and
      returns the corresponding number. Zero is returned on error.
  | "0x0a".hex | » | 10 |  
  | "-1234".hex | » | -4660 |  
  | "0".hex | » | 0 |  
  | "wombat".hex | » | 0 |  | | include? | str.include? aString -> trueorfalsestr.include? aFixnum ->
 trueorfalse | 
 | Returns trueif str contains the given string or character.
  | "hello".include? "lo" | » | true |  
  | "hello".include? "ol" | » | false |  
  | "hello".include? ?h | » | true |  | | index | str.index( aString [, anOffset] )
            -> aFixnum or nilstr.index( aFixnum [, anOffset] )
            -> aFixnum or
 nilstr.index( aRegexp [, anOffset] )
            -> aFixnum or
 nil | 
 | Returns the index of the first occurrence of the given substring,
      character, or pattern in str. Returns nilif not found.
      If the second parameter is present, it specifies the position in
      the string to begin the search.
  | "hello".index('e') | » | 1 |  
  | "hello".index('lo') | » | 3 |  
  | "hello".index('a') | » | nil |  
  | "hello".index(101) | » | 1 |  
  | "hello".index(/[aeiou]/, -3) | » | 4 |  | | intern | str.intern -> aSymbol | 
 | Returns the Symbolcorresponding to str, creating the
      symbol if it did not previously exist. SeeSymbol#id2nameon page 389. | | length | str.length -> anInteger | 
 | Returns the length of str. | | ljust | str.ljust( anInteger )
        -> aString | 
 | If anInteger is greater than the length of str, returns a
      new Stringof length anInteger with str left
      justified and space padded; otherwise, returns str.
  | "hello".ljust(4) | » | "hello" |  
  | "hello".ljust(20) | » | "hello![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) " |  | | next | str.next
        -> aString | 
 | Synonym for String#succ. | | next! | str.next! -> str | 
 | Synonym for String#succ!. | | oct | str.oct
        -> anInteger | 
 | Treats str as a string of octal digits (with an optional 
      sign) and returns the corresponding number.  Returns 0 if the
      conversion fails. 
  | "123".oct | » | 83 |  
  | "-377".oct | » | -255 |  
  | "bad".oct | » | 0 |  
  | "0377bad".oct | » | 255 |  | | replace | str.replace( aString )
        -> str | 
 | Replaces the contents and taintedness of str with the
      corresponding values in aString. 
  | s = "hello" | » | "hello" |  
  | s.replace "world" | » | "world" |  | | reverse | str.reverse
        -> aString | 
 | Returns a new string  with the characters from str in
      reverse order. 
  | "stressed".reverse | » | "desserts" |  | | reverse! | str.reverse! -> str | 
 | Reverses str in place. | | rindex | str.rindex( aString [, aFixnum] )
            -> aFixnum or nilstr.rindex( aFixnum [, aFixnum] )
            -> aFixnum or
 nilstr.rindex( aRegexp [, aFixnum] )
            -> aFixnum or
 nil | 
 | Returns the index of the last occurrence of the given substring,
      character, or pattern in str. Returns nilif not found.
      If the second parameter is present, it specifies the position in
      the string to end the search---characters beyond this point will 
      not be considered.
  | "hello".rindex('e') | » | 1 |  
  | "hello".rindex('l') | » | 3 |  
  | "hello".rindex('a') | » | nil |  
  | "hello".rindex(101) | » | 1 |  
  | "hello".rindex(/[aeiou]/, -2) | » | 1 |  | | rjust | str.rjust( anInteger )
        -> aString | 
 | If anInteger is greater than the length of str,
      returns a new Stringof length
      anInteger with str right justified and space padded;
      otherwise, returns str.
  | "hello".rjust(4) | » | "hello" |  
  | "hello".rjust(20) | » | "![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) ![[visible space]](visible_space.gif) hello" |  | | scan | str.scan( pattern ) -> anArray str.scan( pattern ) {| match, ...| block }
 -> str
 | 
 | Both forms iterate through str, matching the pattern (which
      may be a Regexpor aString). For each match, a result
      is generated and either added 
      to the result array or passed to the block. If the pattern
      contains no groups, each individual result consists of the matched
      string,$&. If the pattern contains groups, each
      individual result is itself an array containing one entry per group.
And the block form:
| a = "cruel world" |  
  | a.scan(/\w+/) | » | ["cruel", "world"] |  
  | a.scan(/.../) | » | ["cru", "el ", "wor"] |  
  | a.scan(/(...)/) | » | [["cru"], ["el "], ["wor"]] |  
  | a.scan(/(..)(..)/) | » | [["cr", "ue"], ["l ", "wo"]] |  produces:| 
a.scan(/\w+/) {|w| print "<<#{w}>> " }
print "\n"
a.scan(/(.)(.)/) {|a,b| print b, a }
print "\n"
 | 
 | 
<<cruel>> <<world>>
rceu lowlr
 | 
 | | size | str.size -> anInteger | 
 | Synonym for String#length. | | slice | str.slice( aFixnum ) -> aFixnum or nilstr.slice( aFixnum, aFixnum )
                                        -> aString or
 nilstr.slice( aRange ) -> aString or
 nilstr.slice( aRegexp ) -> aString or
 nilstr.slice( aString ) -> aString or
 nil | 
 | Synonym for String#[ ].
| a = "hello there" |  
  | a.slice(1) | » | 101 |  
  | a.slice(1,3) | » | "ell" |  
  | a.slice(1..3) | » | "ell" |  
  | a.slice(-3,2) | » | "er" |  
  | a.slice(-4..-2) | » | "her" |  
  | a.slice(-2..-4) | » | nil |  
  | a.slice(/th[aeiou]/) | » | "the" |  
  | a.slice("lo") | » | "lo" |  
  | a.slice("bye") | » | nil |  | | slice! | str.slice!( aFixnum ) -> aFixnum or nilstr.slice!( aFixnum, aFixnum )
                                        -> aString or
 nilstr.slice!( aRange ) -> aString or
 nilstr.slice!( aRegexp ) -> aString or
 nilstr.slice!( aString ) -> aString or
 nil | 
 | Deletes the specified portion from str, and returns the portion
      deleted.         The forms that take a Fixnumwill raise anIndexErrorif the value is out of range; theRangeform will raise aRangeError, and theRegexpandStringforms will silently ignore the assignment.
| string = "this is a string" |  
  | string.slice!(2) | » | 105 |  
  | string.slice!(3..6) | » | " is " |  
  | string.slice!(/s.*t/) | » | "sa st" |  
  | string.slice!("r") | » | "r" |  
  | string | » | "thing" |  | | split | str.split( pattern= $;,
          [limit] ) -> anArray | 
 | Divides str into substrings based on a delimiter, returning
      an array of these substrings.
      If pattern is a String, then its contents are used as 
      the delimiter when splitting str. If pattern is a
      single space, str is split on whitespace, with leading
      whitespace and runs of contiguous whitespace characters ignored.
      If pattern is aRegexp, str is divided where the
      pattern matches. Whenever the pattern matches a zero-length string,
      str is split into individual characters.
      If pattern is omitted, the value of$;is
      used. If$;isnil(which is the default),
      str is split on whitespace as if `![[visible space]](visible_space.gif) ' were specified.
      If the limit parameter is omitted, trailing null fields are
      supressed. If limit is a positive number, at most that
      number of fields will be returned (if limit is 1,
      the entire string is returned as the only entry in an array). If
      negative, there is no limit to the number of fields returned,
      and trailing null fields are not supressed.
  | " now's  the time".split | » | ["now's", "the", "time"] |  
  | " now's  the time".split(' ') | » | ["now's", "the", "time"] |  
  | " now's  the time".split(/ /) | » | ["", "now's", "", "the", "time"] |  
  | "1, 2.34,56, 7".split(/,\s*/) | » | ["1", "2.34", "56", "7"] |  
  | "hello".split(//) | » | ["h", "e", "l", "l", "o"] |  
  | "hello".split(//, 3) | » | ["h", "e", "llo"] |  
  | "hi mom".split(/\s*/) | » | ["h", "i", "m", "o", "m"] |  
  | "mellow yellow".split("ello") | » | ["m", "w y", "w"] |  
  | "1,2,,3,4,,".split(',') | » | ["1", "2", "", "3", "4"] |  
  | "1,2,,3,4,,".split(',', 4) | » | ["1", "2", "", "3,4,,"] |  
  | "1,2,,3,4,,".split(',', -4) | » | ["1", "2", "", "3", "4", "", ""] |  | | squeeze | str.squeeze( [aString]* )
        -> aNewString | 
 | Builds a set of characters from the aString parameter(s)
      using the procedure described for String#counton page 373. Returns a new string where runs of
      the same character that occur in this set are replaced
      by a single character. If no arguments are given,
      all runs of identical characters are replaced by a single
      character.
  | "yellow moon".squeeze | » | "yelow mon" |  
  | "  now   is  the".squeeze(" ") | » | " now is the" |  
  | "putters shoot balls".squeeze("m-z") | » | "puters shot balls" |  | | squeeze! | str.squeeze!( [aString]* )
        -> str or nil | 
 | Squeezes str in place, returning either str, or nilif no changes were made. | | strip | str.strip -> aString | 
 | Returns a copy of str with leading and trailing whitespace removed. 
  | "    hello    ".strip | » | "hello" |  
  | "\tgoodbye\r\n".strip | » | "goodbye" |  | | strip! | str.strip! -> str or nil | 
 | Removes leading and trailing whitespace from str. Returns nilif str was not altered. | | sub | str.sub( pattern, replacement )
          -> aString str.sub( pattern ) {| match | block }
 -> aString
 | 
 | Returns a copy of str with the first occurrence of
        pattern replaced with either replacement or the
        value of the block. If the string form of the method is used,
        special variables such as $&will not be useful, as
        substitution into the string occurs before the pattern match
        starts. However, the sequences\1,\2,
        listed in Table 22.7 on page 376 may be used.
        In the block form, the current match is passed in as a
        parameter, and variables such as$1,$2,$`,$&, and$'will be set appropriately. The value returned by the block
        will be substituted for the match on each call.
  | "hello".sub(/[aeiou]/, '*') | » | "h*llo" |  
  | "hello".sub(/([aeiou])/, '<\1>') | » | "h<e>llo" |  
  | "hello".sub('.') {|s| s[0].to_s + ' ' } | » | "104 ello" |  | | sub! | str.sub!( pattern, replacement )
          -> str or nilstr.sub!( pattern ) {| match | block }
          -> str or
 nil | 
 | Performs the substitutions of String#subin place,
      returning str, ornilif no substitutions were
      performed. | | succ | str.succ
        -> aString | 
 | Returns the successor to str. The successor is calculated by
      incrementing characters starting from the rightmost 
      alphanumeric (or the rightmost character if there are no
      alphanumerics) in the string. Incrementing a digit always results
      in another digit, and incrementing a letter results in another
      letter of the same case. Incrementing nonalphanumerics uses the 
      underlying character set's collating sequence.
      If the increment generates a ``carry,'' the character to the
      left of it is incremented. This process repeats until there is
      no carry, adding an additional character if necessary. 
  | "abcd".succ | » | "abce" |  
  | "THX1138".succ | » | "THX1139" |  
  | "<<koala>>".succ | » | "<<koalb>>" |  
  | "1999zzz".succ | » | "2000aaa" |  
  | "ZZZ9999".succ | » | "AAAA0000" |  
  | "***".succ | » | "**+" |  | | succ! | str.succ! -> str | 
 | Equivalent to String#succ, but modifies the receiver in place. | | sum | str.sum( aFixnum=16 )
        -> anInteger | 
 | Returns a basic      
      n-bit checksum of the characters in
      str, where n is the optional parameter, defaulting to 16. The
      result is simply the sum of the binary value of each character
      in str modulo 2n - 1. This is not a particularly good checksum. | | swapcase | str.swapcase -> aString | 
 | Returns a copy of str with uppercase alphabetic characters 
      converted to lowercase and lowercase characters converted to uppercase. 
  | "Hello".swapcase | » | "hELLO" |  
  | "cYbEr_PuNk11".swapcase | » | "CyBeR_pUnK11" |  | | swapcase! | str.swapcase! -> str or nil | 
 | Equivalent to String#swapcase, but modifies the receiver in
      place, returning str, ornilif no changes were
      made. | | to_f | str.to_f -> aFloat | 
 | Returns the result of interpreting leading characters in str
      as a floating point number. Extraneous characters past the end
      of a valid number are ignored. If there is not a valid number at 
      the start of str, 0.0is returned. The method never
      raises an exception.
  | "123.45e1".to_f | » | 1234.5 |  
  | "45.67 degrees".to_f | » | 45.67 |  
  | "thx1138".to_f | » | 0.0 |  | | to_i | str.to_i -> anInteger | 
 | Returns the result of interpreting leading characters in str
      as a decimal integer. Extraneous characters past the end
      of a valid number are ignored. If there is not a valid number at 
      the start of str, 0is returned. The method never
      raises an exception.
  | "12345".to_i | » | 12345 |  
  | "99 red balloons".to_i | » | 99 |  
  | "0x0a".to_i | » | 0 |  
  | "hello".to_i | » | 0 |  | | to_s | str.to_s -> str | 
 | Returns the receiver. | | to_str | str.to_str -> str | 
 | Synonym for String#to_s.to_stris
      used by methods such asString#concatto convert their
      arguments to a string. Unliketo_s, which is supported 
      by almost all classes,to_stris normally implemented
      only by those classes that act like strings. Of the built-in
      classes, onlyExceptionandStringimplementto_str. | | tr | str.tr( fromString, toString )
        -> aString | 
 | Returns a copy of str with the characters in
      fromString replaced by the corresponding characters in
      toString. If toString is shorter than
      fromString, it is padded with its last character. Both
      strings may use the c1--c2 notation to denote ranges of
      characters, and fromString may start with a ^,
      which denotes all characters except those listed.
  | "hello".tr('aeiou', '*') | » | "h*ll*" |  
  | "hello".tr('^aeiou', '*') | » | "*e**o" |  
  | "hello".tr('el', 'ip') | » | "hippo" |  
  | "hello".tr('a-y', 'b-z') | » | "ifmmp" |  | | tr! | str.tr!( fromString, toString )
        -> str or nil | 
 | Translates str in place, using the same rules as String#tr. Returns str, ornilif no changes were 
      made. | | tr_s | str.tr_s( fromString, toString )
        -> aString | 
 | Processes a copy of str as described under String#tr,
      then removes duplicate characters in regions that were affected
      by the translation.
  | "hello".tr_s('l', 'r') | » | "hero" |  
  | "hello".tr_s('el', '*') | » | "h*o" |  
  | "hello".tr_s('el', 'hx') | » | "hhxo" |  | | tr_s! | str.tr_s!( fromString, toString )
        -> str or nil | 
 | Performs String#tr_sprocessing on str in place,
      returning str, ornilif no changes were made. | | unpack | str.unpack( format )
        -> anArray | 
 | Decodes      
      str (which may contain binary data) according to the format
      string, returning an array of each value extracted.  The format
      string consists of a sequence of single-character directives,
      summarized in Table 22.8 on page 384.  Each directive may be
      followed by a number, indicating the number of times to repeat
      with this directive.  An asterisk (`` *'') will use up all
      remaining elements.  The directivessSiIlLmay each be followed
      by an underscore (``_'') to use the underlying platform's
      native size for the specified type; otherwise, it uses a
      platform-independent consistent size.  Spaces are ignored in the format
      string. See alsoArray#packon page 290.| Directives for String#unpack
1 May be modified by appending ``_'' to the directive.
  | Format | Function | Returns |  
  | A | String with trailing nulls and spaces removed. | String |  
  | a | String. | String |  
  | B | Extract bits from each character (msb first). | String |  
  | b | Extract bits from each character (lsb first). | String |  
  | C | Extract a character as an unsigned integer. | Fixnum |  
  | c | Extract a character as an integer. | Fixnum |  
  | d | Treat sizeof(double) characters as a native
          double. | Float |  
  | E | Treat sizeof(double) characters as a double in
          little-endian byte order. | Float |  
  | e | Treat sizeof(float) characters as a float in
          little-endian byte order. | Float |  
  | f | Treat sizeof(float) characters as a native float. | Float |  
  | G | Treat sizeof(double) characters as a double in
          network byte order. | Float |  
  | g | Treat sizeof(float) characters as a float in
          network byte order. | Float |  
  | H | Extract hex nibbles from each character (most
          significant first). | String |  
  | h | Extract hex nibbles from each character (least
          significant first). | String |  
  | I | Treat sizeof(int)1 successive
          characters as an unsigned native integer. | Integer |  
  | i | Treat sizeof(int)1 successive
          characters as a signed native integer. | Integer |  
  | L | Treat four1 successive
          characters as an unsigned native
          long integer. | Integer |  
  | l | Treat four1 successive
          characters as a signed native
          long integer. | Integer |  
  | M | Extract a quoted-printable string. | String |  
  | m | Extract a base64 encoded string. | String |  
  | N | Treat four characters as an unsigned long in network
          byte order. | Fixnum |  
  | n | Treat two characters as an unsigned short in network
          byte order. | Fixnum |  
  | P | Treat sizeof(char *) characters as a pointer, and 
          return len characters from the referenced location. | String |  
  | p | Treat sizeof(char *) characters as a pointer to a 
          null-terminated string. | String |  
  | S | Treat two1 successive characters as an unsigned
          short in
          native byte order. | Fixnum |  
  | s | Treat two1 successive
          characters as a signed short in
          native byte order. | Fixnum |  
  | U | Extract UTF-8 characters as unsigned integers. | Integer |  
  | u | Extract a UU-encoded string. | String |  
  | V | Treat four characters as an unsigned long in little-endian
          byte order. | Fixnum |  
  | v | Treat two characters as an unsigned short in little-endian
          byte order. | Fixnum |  
  | X | Skip backward one character. | --- |  
  | x | Skip forward one character. | --- |  
  | Z | String with trailing nulls removed. | String |  
  | @ | Skip to the offset given by the length argument. | --- |  |  |  | 
 
  | "abc \0\0abc \0\0".unpack('A6Z6') | » | ["abc", "abc "] |  
  | "abc \0\0".unpack('a3a3') | » | ["abc", " \000\000"] |  
  | "aa".unpack('b8B8') | » | ["10000110", "01100001"] |  
  | "aaa".unpack('h2H2c') | » | ["16", "61", 97] |  
  | "\xfe\xff\xfe\xff".unpack('sS') | » | [-2, 65534] |  
  | "now=20is".unpack('M*') | » | ["now is"] |  
  | "whole".unpack('xax2aX2aX1aX2a') | » | ["h", "e", "l", "l", "o"] |  | | upcase | str.upcase -> aString | 
 | Returns a copy of str with all lowercase letters replaced
      with their uppercase counterparts. The operation is locale
      insensitive---only characters ``a'' to ``z'' are affected. | | upcase! | str.upcase! -> str or nil | 
 | Upcases the contents of str, returning nilif no
      changes were made. | | upto | str.upto( aString )
        {| s | block }
 -> str | 
 | Iterates through successive values, starting at str and
      ending at aString inclusive, passing each value in turn to
      the block. The String#succmethod is used to generate each
      value.produces:| 
"a8".upto("b6") {|s| print s, ' ' }
for s in "a8".."b6"
  print s, ' '
end
 | 
 | 
a8 a9 b0 b1 b2 b3 b4 b5 b6
a8 a9 b0 b1 b2 b3 b4 b5 b6
 | 
 |