Prevents further modifications to obj. A FrozenError
will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?
.
This method returns self.
a = [ "a", "b", "c" ] a.freeze a << "z"
produces:
prog.rb:3:in `<<': can't modify frozen Array (FrozenError) from prog.rb:3
Objects of the following classes are always frozen: Integer
, Float
, Symbol
.
Invokes Module.prepend_features
on each parameter in reverse order.
The equivalent of included
, but for prepended modules.
module A def self.prepended(mod) puts "#{self} prepended to #{mod}" end end module Enumerable prepend A end # => prints "A prepended to Enumerable"
Returns an integer representing the mode settings for exception handling and rounding.
These modes control exception handling:
BigDecimal::EXCEPTION_NaN.
BigDecimal::EXCEPTION_INFINITY.
BigDecimal::EXCEPTION_UNDERFLOW.
BigDecimal::EXCEPTION_OVERFLOW.
BigDecimal::EXCEPTION_ZERODIVIDE.
BigDecimal::EXCEPTION_ALL.
Values for setting
for exception handling:
true
: sets the given mode
to true
.
false
: sets the given mode
to false
.
nil
: does not modify the mode settings.
You can use method BigDecimal.save_exception_mode
to temporarily change, and then automatically restore, exception modes.
For clarity, some examples below begin by setting all exception modes to false
.
This mode controls the way rounding is to be performed:
BigDecimal::ROUND_MODE
You can use method BigDecimal.save_rounding_mode
to temporarily change, and then automatically restore, the rounding mode.
NaNs
Mode BigDecimal::EXCEPTION_NaN controls behavior when a BigDecimal NaN is created.
Settings:
false
(default): Returns BigDecimal('NaN')
.
true
: Raises FloatDomainError
.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 BigDecimal('NaN') # => NaN BigDecimal.mode(BigDecimal::EXCEPTION_NaN, true) # => 2 BigDecimal('NaN') # Raises FloatDomainError
Infinities
Mode BigDecimal::EXCEPTION_INFINITY controls behavior when a BigDecimal Infinity or -Infinity is created. Settings:
false
(default): Returns BigDecimal('Infinity')
or BigDecimal('-Infinity')
.
true
: Raises FloatDomainError
.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 BigDecimal('Infinity') # => Infinity BigDecimal('-Infinity') # => -Infinity BigDecimal.mode(BigDecimal::EXCEPTION_INFINITY, true) # => 1 BigDecimal('Infinity') # Raises FloatDomainError BigDecimal('-Infinity') # Raises FloatDomainError
Underflow
Mode BigDecimal::EXCEPTION_UNDERFLOW controls behavior when a BigDecimal underflow occurs. Settings:
false
(default): Returns BigDecimal('0')
or BigDecimal('-Infinity')
.
true
: Raises FloatDomainError
.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 def flow_under x = BigDecimal('0.1') 100.times { x *= x } end flow_under # => 100 BigDecimal.mode(BigDecimal::EXCEPTION_UNDERFLOW, true) # => 4 flow_under # Raises FloatDomainError
Overflow
Mode BigDecimal::EXCEPTION_OVERFLOW controls behavior when a BigDecimal overflow occurs. Settings:
false
(default): Returns BigDecimal('Infinity')
or BigDecimal('-Infinity')
.
true
: Raises FloatDomainError
.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 def flow_over x = BigDecimal('10') 100.times { x *= x } end flow_over # => 100 BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true) # => 1 flow_over # Raises FloatDomainError
Zero Division
Mode BigDecimal::EXCEPTION_ZERODIVIDE controls behavior when a zero-division occurs. Settings:
false
(default): Returns BigDecimal('Infinity')
or BigDecimal('-Infinity')
.
true
: Raises FloatDomainError
.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 one = BigDecimal('1') zero = BigDecimal('0') one / zero # => Infinity BigDecimal.mode(BigDecimal::EXCEPTION_ZERODIVIDE, true) # => 16 one / zero # Raises FloatDomainError
All Exceptions
Mode BigDecimal::EXCEPTION_ALL controls all of the above:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0 BigDecimal.mode(BigDecimal::EXCEPTION_ALL, true) # => 23
Rounding
Mode BigDecimal::ROUND_MODE controls the way rounding is to be performed; its setting
values are:
ROUND_UP
: Round away from zero. Aliased as :up
.
ROUND_DOWN
: Round toward zero. Aliased as :down
and :truncate
.
ROUND_HALF_UP
: Round toward the nearest neighbor; if the neighbors are equidistant, round away from zero. Aliased as :half_up
and :default
.
ROUND_HALF_DOWN
: Round toward the nearest neighbor; if the neighbors are equidistant, round toward zero. Aliased as :half_down
.
ROUND_HALF_EVEN
(Banker’s rounding): Round toward the nearest neighbor; if the neighbors are equidistant, round toward the even neighbor. Aliased as :half_even
and :banker
.
ROUND_CEILING
: Round toward positive infinity. Aliased as :ceiling
and :ceil
.
ROUND_FLOOR
: Round toward negative infinity. Aliased as :floor:
.
Returns an Array
of two Integer
values that represent platform-dependent internal storage properties.
This method is deprecated and will be removed in the future. Instead, use BigDecimal#n_significant_digits
for obtaining the number of significant digits in scientific notation, and BigDecimal#precision
for obtaining the number of digits in decimal notation.
Divides by the specified value, and returns the quotient and modulus as BigDecimal
numbers. The quotient is rounded towards negative infinity.
For example:
require 'bigdecimal' a = BigDecimal("42") b = BigDecimal("9") q, m = a.divmod(b) c = q * b + m a == c #=> true
The quotient q is (a/b).floor, and the modulus is the amount that must be added to q * b to get a.
Returns true
if rat
is greater than 0.
Returns true
if rat
is less than 0.
Returns a hash of values parsed from string
, which should be a valid XML date format:
d = Date.new(2001, 2, 3) s = d.xmlschema # => "2001-02-03" Date._xmlschema(s) # => {:year=>2001, :mon=>2, :mday=>3}
See argument limit.
Related: Date.xmlschema
(returns a Date object).
Returns a new Date object with values parsed from string
, which should be a valid XML date format:
d = Date.new(2001, 2, 3) s = d.xmlschema # => "2001-02-03" Date.xmlschema(s) # => #<Date: 2001-02-03>
See:
Argument start.
Argument limit.
Related: Date._xmlschema
(returns a hash).
Returns true
if the date is on or after the date of calendar reform, false
otherwise:
Date.new(1582, 10, 15).gregorian? # => true (Date.new(1582, 10, 15) - 1).gregorian? # => false
Equivalent to Date#new_start
with argument Date::GREGORIAN
.
Equivalent to strftime
with argument '%Y-%m-%d'
(or its shorthand form '%F'
);
Date.new(2001, 2, 3).iso8601 # => "2001-02-03"
Creates a new DateTime
object by parsing from a string according to some typical XML Schema formats.
DateTime.xmlschema('2001-02-03T04:05:06+07:00') #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
Raise an ArgumentError
when the string length is longer than limit. You can stop this check by passing limit: nil
, but note that it may take a long time to parse.
This method is equivalent to strftime(‘%FT%T%:z’). The optional argument n
is the number of digits for fractional seconds.
DateTime.parse('2001-02-03T04:05:06.123456789+07:00').iso8601(9) #=> "2001-02-03T04:05:06.123456789+07:00"
Parses time
as a dateTime defined by the XML Schema and converts it to a Time
object. The format is a restricted version of the format defined by ISO 8601.
ArgumentError
is raised if time
is not compliant with the format or if the Time
class cannot represent the specified time.
See xmlschema
for more information on this format.
require 'time' Time.xmlschema("2011-10-05T22:26:12-04:00") #=> 2011-10-05 22:26:12-04:00
You must require ‘time’ to use this method.
Returns a string which represents the time as a dateTime defined by XML Schema:
CCYY-MM-DDThh:mm:ssTZD CCYY-MM-DDThh:mm:ss.sssTZD
where TZD is Z or [+-]hh:mm.
If self is a UTC time, Z is used as TZD. [+-]hh:mm is used otherwise.
fraction_digits
specifies a number of digits to use for fractional seconds. Its default value is 0.
require 'time' t = Time.now t.iso8601 # => "2011-10-05T22:26:12-04:00"
You must require ‘time’ to use this method.
Returns number of bytes that can be read without blocking. Returns zero if no information available.
You must require ‘io/wait’ to use this method.
Returns a truthy value if input available without blocking, or a falsy value.
You must require ‘io/wait’ to use this method.
Calls the block with each successive line read from the stream.
When called from class IO (but not subclasses of IO), this method has potential security vulnerabilities if called with untrusted input; see Command Injection.
The first argument must be a string that is the path to a file.
With only argument path
given, parses lines from the file at the given path
, as determined by the default line separator, and calls the block with each successive line:
File.foreach('t.txt') {|line| p line }
Output: the same as above.
For both forms, command and path, the remaining arguments are the same.
With argument sep
given, parses lines as determined by that line separator (see Line Separator):
File.foreach('t.txt', 'li') {|line| p line }
Output:
"First li" "ne\nSecond li" "ne\n\nThird li" "ne\nFourth li" "ne\n"
Each paragraph:
File.foreach('t.txt', '') {|paragraph| p paragraph }
Output:
"First line\nSecond line\n\n" "Third line\nFourth line\n"
With argument limit
given, parses lines as determined by the default line separator and the given line-length limit (see Line Limit):
File.foreach('t.txt', 7) {|line| p line }
Output:
"First l" "ine\n" "Second " "line\n" "\n" "Third l" "ine\n" "Fourth l" "line\n"
With arguments sep
and limit
given, parses lines as determined by the given line separator and the given line-length limit (see Line Separator and Line Limit):
Optional keyword arguments opts
specify:
Encoding options.
Returns an Enumerator
if no block is given.
Returns an array of all lines read from the stream.
When called from class IO (but not subclasses of IO), this method has potential security vulnerabilities if called with untrusted input; see Command Injection.
The first argument must be a string that is the path to a file.
With only argument path
given, parses lines from the file at the given path
, as determined by the default line separator, and returns those lines in an array:
IO.readlines('t.txt') # => ["First line\n", "Second line\n", "\n", "Third line\n", "Fourth line\n"]
With argument sep
given, parses lines as determined by that line separator (see Line Separator):
# Ordinary separator. IO.readlines('t.txt', 'li') # =>["First li", "ne\nSecond li", "ne\n\nThird li", "ne\nFourth li", "ne\n"] # Get-paragraphs separator. IO.readlines('t.txt', '') # => ["First line\nSecond line\n\n", "Third line\nFourth line\n"] # Get-all separator. IO.readlines('t.txt', nil) # => ["First line\nSecond line\n\nThird line\nFourth line\n"]
With argument limit
given, parses lines as determined by the default line separator and the given line-length limit (see Line Limit):
IO.readlines('t.txt', 7) # => ["First l", "ine\n", "Second ", "line\n", "\n", "Third l", "ine\n", "Fourth ", "line\n"]
With arguments sep
and limit
given, parses lines as determined by the given line separator and the given line-length limit (see Line Separator and Line Limit):
Optional keyword arguments opts
specify:
Encoding options.