|
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 Array containing the
values to be substituted. See
Kernel::sprintf
on page 423 for details of the format string.
"%05d" % 123
|
» |
"00123"
|
"%-5s: %08x" % [ "ID", self.id ]
|
» |
"ID![[visible space]](visible_space.gif) :200e1670"
|
|
|
*
|
str * anInteger
-> aString
|
|
Copy---Returns a new String containing anInteger copies of
the receiver.
"Ho! " * 3
|
» |
"Ho! Ho! Ho! "
|
|
|
+
|
str + aString
-> aNewString
|
|
Concatenation---Returns a new String containing
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
Fixnum between 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 $= is false, the comparison is based
on comparing the binary values of each character in the string.
If $= is not false, 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 <,
<=, >, >=, and between?,
included from module Comparable. The method
String#==
does not use
Comparable#==
.
"abcdef" <=> "abcde"
|
» |
1
|
"abcdef" <=> "abcdef"
|
» |
0
|
"abcdef" <=> "abcdefg"
|
» |
-1
|
"abcdef" <=> "ABCDEF"
|
» |
1
|
$= = true
|
"abcdef" <=> "ABCDEF"
|
» |
0
|
|
|
==
|
str == anObject
-> true or false
|
|
Equality---If anObject is not a String, returns
false. Otherwise, returns true if str <=>
anObject returns zero.
|
|
===
|
str === anObject
-> true or false
|
|
Case Equality---Synonym for
String#==
.
|
|
=~
|
str =~ anObject
-> aFixnum or nil
|
|
Match---If anObject is a Regexp or a String, uses it as a
pattern to match against str. Returns
the position the match starts, or nil if there is no match.
Otherwise, invokes
anObject.=~, passing str as an argument. The
default =~ in Object returns false.
"cat o' 9 tails" =~ "\\d"
|
» |
7
|
"cat o' 9 tails" =~ /\d/
|
» |
7
|
"cat o' 9 tails" =~ 9
|
» |
false
|
|
|
[ ]
|
str[ aFixnum ] -> aFixnum or nil
str[ aFixnum, aFixnum ] -> aString or nil
str[ aRange ] -> aString or nil
str[ aRegexp ] -> aString or nil
str[ aString ] -> aString or nil
|
|
Element Reference---If passed a single Fixnum, returns the
code of the character at that position. If passed two
Fixnum objects, 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. Returns nil
if the initial offset falls outside the string, the length is
negative, or the beginning of the range is greater than the
end.
If a Regexp is supplied, the matching portion of str is
returned. If a String is given, that string is returned if it
occurs in str. In both cases, nil is 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 a Fixnum will raise an
IndexError if the value is out of range; the Range
form will raise a RangeError, and the Regexp and
String forms 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 $_
=~ str
.
|
|
capitalize
|
str.capitalize
-> aString
|
|
Returns a copy of str with the first character converted to
uppercase and the remainder to lowercase.
"hello".capitalize
|
» |
"Hello"
|
"HELLO".capitalize
|
» |
"Hello"
|
"123ABC".capitalize
|
» |
"123abc"
|
|
|
capitalize!
|
str.capitalize!
-> str or nil
|
|
Modifies str by converting the first character to
uppercase and the remainder to lowercase. Returns nil if
no changes are made.
a = "hello"
|
a.capitalize!
|
» |
"Hello"
|
a
|
» |
"Hello"
|
a.capitalize!
|
» |
nil
|
|
|
center
|
str.center( anInteger )
-> aString
|
|
If anInteger is greater than the length of str, returns a
new String of length anInteger with str centered
between spaces; otherwise,
returns str.
"hello".center(4)
|
» |
"hello"
|
"hello".center(20)
|
» |
"hello"
|
|
|
chomp
|
str.chomp( aString=$/ )
-> aString
|
|
Returns a new String with 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 or nil
|
|
Modifies str in place as described for
String#chomp
,
returning str, or nil if no modifications were made.
|
|
chop
|
str.chop
-> aString
|
|
Returns a new String with the last character removed. If the
string ends with \r\n, both characters are
removed. Applying chop to an empty string returns an
empty string.
String#chomp
is 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,
or nil if str is the empty string. See also
String#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 delete operation in place, returning str, or
nil if 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 nil if no
changes were made.
|
|
dump
|
str.dump -> aString
|
|
Produces a version of str with all nonprinting characters
replaced by \nnn notation and all special characters
escaped.
|
|
each
|
str.each( aString=$/ )
{| substr | block }
-> str
|
|
Splits str using the supplied parameter as the record
separator ($/ by default), passing each substring in turn
to the supplied block. If a zero-length record separator is
supplied, the string is split on \n characters, except
that multiple successive newlines are appended together.
print "Example one\n"
"hello\nworld".each {|s| p s}
print "Example two\n"
"hello\nworld".each('l') {|s| p s}
print "Example three\n"
"hello\n\n\nworld".each('') {|s| p s}
|
produces:
Example one
"hello\n"
"world"
Example two
"hel"
"l"
"o\nworl"
"d"
Example three
"hello\n\n\n"
"world"
|
|
|
each_byte
|
str.each_byte {| aFixnum | block }
-> str
|
|
Passes each byte in str to the given block.
"hello".each_byte {|c| print c, ' ' }
|
produces:
|
|
each_line
|
str.each_line( aString=$/ )
{| substr | block }
-> str
|
|
Synonym for
String#each
.
|
|
empty?
|
str.empty? -> true or false
|
|
Returns true if 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 371.
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 |
 |
|
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.
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 nil
str.gsub!( pattern ) {| match | block }
-> str or nil
|
|
Performs the substitutions of
String#gsub
in place,
returning str, or nil if no substitutions were
performed.
|
|
hash
|
str.hash -> aFixnum
|
|
Generates a Fixnum hash value for str. If $= is
true, 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
|
» |
{"cat"=>"Feline", "dog"=>"canine"}
|
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 -> true or false
str.include? aFixnum -> true or false
|
|
Returns true if 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 nil
str.index( aFixnum [, anOffset
] )
-> aFixnum or nil
str.index( aRegexp [, anOffset
] )
-> aFixnum or nil
|
|
Returns the index of the first occurrence of the given substring,
character, or pattern in str. Returns nil if 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 Symbol corresponding to str, creating the
symbol if it did not previously exist. See
Symbol#id2name
on page 384.
|
|
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 String of length anInteger with str left
justified and space padded; otherwise, returns str.
"hello".ljust(4)
|
» |
"hello"
|
"hello".ljust(20)
|
» |
"hello"
|
|
|
next
|
str.next
-> aString
|
|
Synonym for
String#succ
.
|
|
next!
|
str.next! -> str
|
|
Synonym for
String#succ!
.
|
|
oct
|
str.oct
-> anInteger
|
|
Treats leading characters of 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 nil
str.rindex( aFixnum [, aFixnum
] )
-> aFixnum or nil
str.rindex( aRegexp [, aFixnum
] )
-> aFixnum or nil
|
|
Returns the index of the last occurrence of the given substring,
character, or pattern in str. Returns nil if 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 String of length
anInteger with str right justified and space padded;
otherwise, returns str.
"hello".rjust(4)
|
» |
"hello"
|
"hello".rjust(20)
|
» |
"hello"
|
|
|
scan
|
str.scan( pattern ) -> anArray
str.scan( pattern ) {| match, ...| block }
-> str
|
|
Both forms iterate through str, matching the pattern (which
may be a Regexp or a String). 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, $&. If the pattern contains groups, each
individual result is itself an array containing one entry per group.
a = "cruel world"
|
a.scan(/\w+/)
|
» |
["cruel", "world"]
|
a.scan(/.../)
|
» |
["cru", "el ", "wor"]
|
a.scan(/(...)/)
|
» |
[["cru"], ["el "], ["wor"]]
|
a.scan(/(..)(..)/)
|
» |
[["cr", "ue"], ["l ", "wo"]]
|
And the block form:
a.scan(/\w+/) {|w| print "<<#{w}>> " }
print "\n"
a.scan(/(.)(.)/) {|a,b| print b, a }
print "\n"
|
produces:
<<cruel>> <<world>>
rceu lowlr
|
|
|
size
|
str.size -> anInteger
|
|
Synonym for
String#length
.
|
|
slice
|
str.slice( aFixnum ) -> aFixnum or nil
str.slice( aFixnum, aFixnum )
-> aString or nil
str.slice( aRange ) -> aString or nil
str.slice( aRegexp ) -> aString or nil
str.slice( aString ) -> aString or nil
|
|
Synonym for
String#[ ]
.
a = "hello there"
|
a.slice(1)
|
» |
101
|
a.slice(1,3)
|
» |
"ell"
|
a.slice(1..3)
|
» |
"ell"
|
a.slice(-3,2)
|
» |
"er"
|
a.slice(-4..-2)
|
» |
"her"
|
a.slice(-2..-4)
|
» |
nil
|
a.slice(/th[aeiou]/)
|
» |
"the"
|
a.slice("lo")
|
» |
"lo"
|
a.slice("bye")
|
» |
nil
|
|
|
slice!
|
str.slice!( aFixnum ) -> aFixnum or nil
str.slice!( aFixnum, aFixnum )
-> aString or nil
str.slice!( aRange ) -> aString or nil
str.slice!( aRegexp ) -> aString or nil
str.slice!( aString ) -> aString or nil
|
|
Deletes the specified portion from str, and returns the portion
deleted. The forms that take a Fixnum will raise an
IndexError if the value is out of range; the Range
form will raise a RangeError, and the Regexp and
String forms will silently ignore the assignment.
string = "this is a string"
|
string.slice!(2)
|
» |
105
|
string.slice!(3..6)
|
» |
" is "
|
string.slice!(/s.*t/)
|
» |
"sa st"
|
string.slice!("r")
|
» |
"r"
|
string
|
» |
"thing"
|
|
|
split
|
str.split( pattern=$;,
[
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 a Regexp, 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 $; is nil (which is the default),
str is split on whitespace as if `' 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#count
on page 368. 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
nil if 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
nil if 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 371 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 nil
str.sub!( pattern ) {| match | block }
-> str or nil
|
|
Performs the substitutions of
String#sub
in place,
returning str, or nil if 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, or nil if 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, 0.0 is 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, 0 is 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_str is
used by methods such as
String#concat
to convert their
arguments to a string. Unlike to_s, which is supported
by almost all classes, to_str is normally implemented
only by those classes that act like strings. Of the built-in
classes, only Exception
and String implement to_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, or nil if 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_s
processing on str in place,
returning str, or nil if 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 379. 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 directives sSiIlL may 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 also
Array#pack
on page 286.
Directives for
String#unpack
|
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. |
--- |
|
1 May be modified by appending ``_'' to the directive.
|
"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 nil if 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#succ
method is used to generate each
value.
"a8".upto("b6") {|s| print s, ' ' }
for s in "a8".."b6"
print s, ' '
end
|
produces:
a8 a9 b0 b1 b2 b3 b4 b5 b6
a8 a9 b0 b1 b2 b3 b4 b5 b6
|
|