Extracts data from self, forming objects that become the elements of a new array; returns that array. See Packed Data.
Like String#unpack, but unpacks and returns only the first extracted object. See Packed Data.
Returns an unescaped version of self:
s_orig = "\f\x00\xff\\\"" # => "\f\u0000\xFF\\\"" s_dumped = s_orig.dump # => "\"\\f\\x00\\xFF\\\\\\\"\"" s_undumped = s_dumped.undump # => "\f\u0000\xFF\\\"" s_undumped == s_orig # => true
Related: String#dump (inverse of String#undump).
Returns the total number of characters in self that are specified by the given selectors (see Multiple Character Selectors):
a = "hello world" a.count "lo" #=> 5 a.count "lo", "o" #=> 2 a.count "hello", "^l" #=> 4 a.count "ej-m" #=> 4 "hello^world".count "\\^aeiou" #=> 4 "hello-world".count "a\\-eo" #=> 4 c = "hello world\\r\\n" c.count "\\" #=> 2 c.count "\\A" #=> 0 c.count "X-\\w" #=> 3
Returns self rounded to the nearest value with a precision of ndigits decimal digits.
When ndigits is non-negative, returns a float with ndigits after the decimal point (as available):
f = 12345.6789 f.round(1) # => 12345.7 f.round(3) # => 12345.679 f = -12345.6789 f.round(1) # => -12345.7 f.round(3) # => -12345.679
When ndigits is negative, returns an integer with at least ndigits.abs trailing zeros:
f = 12345.6789 f.round(0) # => 12346 f.round(-3) # => 12000 f = -12345.6789 f.round(0) # => -12346 f.round(-3) # => -12000
If keyword argument half is given, and self is equidistant from the two candidate values, the rounding is according to the given half value:
:up or nil: round away from zero:
2.5.round(half: :up) # => 3 3.5.round(half: :up) # => 4 (-2.5).round(half: :up) # => -3
:down: round toward zero:
2.5.round(half: :down) # => 2 3.5.round(half: :down) # => 3 (-2.5).round(half: :down) # => -2
:even: round toward the candidate whose last nonzero digit is even:
2.5.round(half: :even) # => 2 3.5.round(half: :even) # => 4 (-2.5).round(half: :even) # => -2
Raises and exception if the value for half is invalid.
Related: Float#truncate.
Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is positive, returns a float with ndigits digits after the decimal point (as available):
f = 12345.6789 f.truncate(1) # => 12345.6 f.truncate(3) # => 12345.678 f = -12345.6789 f.truncate(1) # => -12345.6 f.truncate(3) # => -12345.678
When ndigits is negative, returns an integer with at least ndigits.abs trailing zeros:
f = 12345.6789 f.truncate(0) # => 12345 f.truncate(-3) # => 12000 f = -12345.6789 f.truncate(0) # => -12345 f.truncate(-3) # => -12000
Note that the limited precision of floating-point arithmetic may lead to surprising results:
(0.3 / 0.1).truncate #=> 2 (!)
Related: Float#round.
Returns:
1, if self is Infinity.
-1 if self is -Infinity.
nil, otherwise.
Examples:
f = 1.0/0.0 # => Infinity f.infinite? # => 1 f = -1.0/0.0 # => -Infinity f.infinite? # => -1 f = 1.0 # => 1.0 f.infinite? # => nil f = 0.0/0.0 # => NaN f.infinite? # => nil
Returns true if self is not Infinity, -Infinity, or NaN, false otherwise:
f = 2.0 # => 2.0 f.finite? # => true f = 1.0/0.0 # => Infinity f.finite? # => false f = -1.0/0.0 # => -Infinity f.finite? # => false f = 0.0/0.0 # => NaN f.finite? # => false
Removes the directory at dirpath from the underlying file system:
Dir.rmdir('foo') # => 0
Raises an exception if the directory is not empty.
Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. Since the underlying implementation relies on the unlink(2) system call, the type of exception raised depends on its error type (see linux.die.net/man/2/unlink) and has the form of e.g. Errno::ENOENT.
See also Dir::rmdir.
Truncates the file file_name to be at most integer bytes long. Not available on all platforms.
f = File.new("out", "w") f.write("1234567890") #=> 10 f.close #=> nil File.truncate("out", 5) #=> 0 File.size("out") #=> 5
Truncates file to at most integer bytes. The file must be opened for writing. Not available on all platforms.
f = File.new("out", "w") f.syswrite("1234567890") #=> 10 f.truncate(5) #=> 0 f.close() #=> nil File.size("out") #=> 5
Round to the nearest integer (by default), returning the result as a BigDecimal if n is specified, or as an Integer if it isn’t.
BigDecimal('3.14159').round #=> 3 BigDecimal('8.7').round #=> 9 BigDecimal('-9.9').round #=> -10 BigDecimal('3.14159').round(2).class.name #=> "BigDecimal" BigDecimal('3.14159').round.class.name #=> "Integer"
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result, and return value will be an Integer.
BigDecimal('3.14159').round(3) #=> 3.142 BigDecimal('13345.234').round(-2) #=> 13300
The value of the optional mode argument can be used to determine how rounding is performed; see BigDecimal.mode.
Returns nil, -1, or +1 depending on whether the value is finite, -Infinity, or +Infinity.
Returns True if the value is finite (not NaN or infinite).
Truncate to the nearest integer (by default), returning the result as a BigDecimal.
BigDecimal('3.14159').truncate #=> 3 BigDecimal('8.7').truncate #=> 8 BigDecimal('-9.9').truncate #=> -9
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').truncate(3) #=> 3.141 BigDecimal('13345.234').truncate(-2) #=> 13300.0
Returns rat truncated (toward zero) to a precision of ndigits decimal digits (default: 0).
When the precision is negative, the returned value is an integer with at least ndigits.abs trailing zeros.
Returns a rational when ndigits is positive, otherwise returns an integer.
Rational(3).truncate #=> 3 Rational(2, 3).truncate #=> 0 Rational(-3, 2).truncate #=> -1 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').truncate(+1).to_f #=> -123.4 Rational('-123.456').truncate(-1) #=> -120
Returns rat rounded to the nearest value with a precision of ndigits decimal digits (default: 0).
When the precision is negative, the returned value is an integer with at least ndigits.abs trailing zeros.
Returns a rational when ndigits is positive, otherwise returns an integer.
Rational(3).round #=> 3 Rational(2, 3).round #=> 1 Rational(-3, 2).round #=> -2 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').round(+1).to_f #=> -123.5 Rational('-123.456').round(-1) #=> -120
The optional half keyword argument is available similar to Float#round.
Rational(25, 100).round(1, half: :up) #=> (3/10) Rational(25, 100).round(1, half: :down) #=> (1/5) Rational(25, 100).round(1, half: :even) #=> (1/5) Rational(35, 100).round(1, half: :up) #=> (2/5) Rational(35, 100).round(1, half: :down) #=> (3/10) Rational(35, 100).round(1, half: :even) #=> (2/5) Rational(-25, 100).round(1, half: :up) #=> (-3/10) Rational(-25, 100).round(1, half: :down) #=> (-1/5) Rational(-25, 100).round(1, half: :even) #=> (-1/5)
Returns true if self is a Sunday, false otherwise.
Returns false
Returns a new Time object whose numeric value is that of self, with its seconds value rounded to precision ndigits:
t = Time.utc(2010, 3, 30, 5, 43, 25.123456789r) t # => 2010-03-30 05:43:25.123456789 UTC t.round # => 2010-03-30 05:43:25 UTC t.round(0) # => 2010-03-30 05:43:25 UTC t.round(1) # => 2010-03-30 05:43:25.1 UTC t.round(2) # => 2010-03-30 05:43:25.12 UTC t.round(3) # => 2010-03-30 05:43:25.123 UTC t.round(4) # => 2010-03-30 05:43:25.1235 UTC t = Time.utc(1999, 12,31, 23, 59, 59) t # => 1999-12-31 23:59:59 UTC (t + 0.4).round # => 1999-12-31 23:59:59 UTC (t + 0.49).round # => 1999-12-31 23:59:59 UTC (t + 0.5).round # => 2000-01-01 00:00:00 UTC (t + 1.4).round # => 2000-01-01 00:00:00 UTC (t + 1.49).round # => 2000-01-01 00:00:00 UTC (t + 1.5).round # => 2000-01-01 00:00:01 UTC
Related: Time#ceil, Time#floor.
Returns true if self represents a Sunday, false otherwise:
t = Time.utc(2000, 1, 2) # => 2000-01-02 00:00:00 UTC t.sunday? # => true
Related: Time#monday?, Time#tuesday?, Time#wednesday?.