Example:
combination([:a, :b, :c, :d]) # => [[:a], [:b], [:c], [:d], [:a, :b], [:a, :c], [:a, :d], [:b, :c], [:b, :d], [:c, :d], [:a, :b, :c], [:a, :b, :d], [:a, :c, :d], [:b, :c, :d], [:a, :b, :c, :d]]
Creates a class to wrap the C union described by signature.
MyUnion = union ['int i', 'char c']
Generate a Table Caption element as a string.
align can be a string, giving the alignment of the caption (one of top, bottom, left, or right). It can be a hash of all the attributes of the element. Or it can be omitted.
The body of the element is provided by the passed-in no-argument block.
caption("left") { "Capital Cities" } # => <CAPTION ALIGN=\"left\">Capital Cities</CAPTION>
Sets OptionParser object, when opt is false or nil, methods OptionParser::Arguable#options and OptionParser::Arguable#options= are undefined. Thus, there is no ways to access the OptionParser object via the receiver object.
Actual OptionParser object, automatically created if nonexistent.
If called with a block, yields the OptionParser object and returns the result of the block. If an OptionParser::ParseError exception occurs in the block, it is rescued, a error message printed to STDERR and nil returned.
Adds to array all elements from each Array in other_arrays; returns self:
a = [0, 1] a.concat([2, 3], [4, 5]) # => [0, 1, 2, 3, 4, 5]
Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is negative, the returned value has at least ndigits.abs trailing zeros:
555.truncate(-1) # => 550 555.truncate(-2) # => 500 -555.truncate(-2) # => -500
Returns self when ndigits is zero or positive.
555.truncate # => 555 555.truncate(50) # => 555
Related: Integer#round.
Returns self truncated (toward zero) to a precision of digits decimal digits.
Numeric implements this by converting self to a Float and invoking Float#truncate.
Concatenates each object in objects to self and returns self:
s = 'foo' s.concat('bar', 'baz') # => "foobarbaz" s # => "foobarbaz"
For each given object object that is an Integer, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"
Related: String#<<, which takes a single argument.
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 the change time for the named file (the time at which directory information about the file was changed, not the file itself).
file_name can be an IO object.
Note that on Windows (NTFS), returns creation time (birth time).
File.ctime("testfile") #=> Wed Apr 09 08:53:13 CDT 2003
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
Returns the change time for file (that is, the time directory information about the file was changed, not the file itself).
Note that on Windows (NTFS), returns creation time (birth time).
File.new("testfile").ctime #=> Wed Apr 09 08:53:14 CDT 2003
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
Returns the number of decimal digits in self:
BigDecimal("0").precision # => 0 BigDecimal("1").precision # => 1 BigDecimal("1.1").precision # => 2 BigDecimal("3.1415").precision # => 5 BigDecimal("-1e20").precision # => 21 BigDecimal("1e-20").precision # => 20 BigDecimal("Infinity").precision # => 0 BigDecimal("-Infinity").precision # => 0 BigDecimal("NaN").precision # => 0
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
Equivalent to strftime with argument '%a %b %e %T %Y' (or its shorthand form '%c'):
Date.new(2001, 2, 3).asctime # => "Sat Feb 3 00:00:00 2001"
See asctime.
Date#ctime is an alias for Date#asctime.
Equivalent to strftime with argument '%a %b %e %T %Y' (or its shorthand form '%c'):
Date.new(2001, 2, 3).asctime # => "Sat Feb 3 00:00:00 2001"
See asctime.
Date#ctime is an alias for Date#asctime.
Returns a string representation of self, formatted by strftime('%a %b %e %T %Y') or its shorthand version strftime('%c'); see Formats for Dates and Times:
t = Time.new(2000, 12, 31, 23, 59, 59, 0.5) t.ctime # => "Sun Dec 31 23:59:59 2000" t.strftime('%a %b %e %T %Y') # => "Sun Dec 31 23:59:59 2000" t.strftime('%c') # => "Sun Dec 31 23:59:59 2000"
Time#asctime is an alias for Time#ctime.
Related: Time#to_s, Time#inspect:
t.inspect # => "2000-12-31 23:59:59.5 +000001" t.to_s # => "2000-12-31 23:59:59 +0000"
Returns a string representation of self, formatted by strftime('%a %b %e %T %Y') or its shorthand version strftime('%c'); see Formats for Dates and Times:
t = Time.new(2000, 12, 31, 23, 59, 59, 0.5) t.ctime # => "Sun Dec 31 23:59:59 2000" t.strftime('%a %b %e %T %Y') # => "Sun Dec 31 23:59:59 2000" t.strftime('%c') # => "Sun Dec 31 23:59:59 2000"
Time#asctime is an alias for Time#ctime.
Related: Time#to_s, Time#inspect:
t.inspect # => "2000-12-31 23:59:59.5 +000001" t.to_s # => "2000-12-31 23:59:59 +0000"
Invokes Posix system call ioctl(2), which issues a low-level command to an I/O device.
Issues a low-level command to an I/O device. The arguments and returned value are platform-dependent. The effect of the call is platform-dependent.
If argument argument is an integer, it is passed directly; if it is a string, it is interpreted as a binary sequence of bytes.
Not implemented on all platforms.
Returns the values in self as an array:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.to_a # => ["Joe Smith", "123 Maple, Anytown NC", 12345]
Struct#values and Struct#deconstruct are aliases for Struct#to_a.
Related: members.