Module Math provides methods for basic trigonometric, logarithmic, and transcendental functions, and for extracting roots.
You can write its constants and method calls thus:
Math::PI # => 3.141592653589793 Math::E # => 2.718281828459045 Math.sin(0.0) # => 0.0 Math.cos(0.0) # => 1.0
If you include module Math, you can write simpler forms:
include Math PI # => 3.141592653589793 E # => 2.718281828459045 sin(0.0) # => 0.0 cos(0.0) # => 1.0
For simplicity, the examples here assume:
include Math INFINITY = Float::INFINITY
The domains and ranges for the methods are denoted by open or closed intervals, using, respectively, parentheses or square brackets:
An open interval does not include the endpoints:
(-INFINITY, INFINITY)
A closed interval includes the endpoints:
[-1.0, 1.0]
A half-open interval includes one endpoint, but not the other:
[1.0, INFINITY)
Many values returned by Math methods are numerical approximations. This is because many such values are, in mathematics, of infinite precision, while in numerical computation the precision is finite.
Thus, in mathematics, cos(π/2) is exactly zero, but in our computation cos(PI/2) is a number very close to zero:
cos(PI/2) # => 6.123031769111886e-17
For very large and very small returned values, we have added formatted numbers for clarity:
tan(PI/2) # => 1.633123935319537e+16 # 16331239353195370.0 tan(PI) # => -1.2246467991473532e-16 # -0.0000000000000001
See class Float for the constants that affect Ruby’s floating-point arithmetic.
::cos: Returns the cosine of the given argument.
::sin: Returns the sine of the given argument.
::tan: Returns the tangent of the given argument.
::acos: Returns the arc cosine of the given argument.
::asin: Returns the arc sine of the given argument.
::atan: Returns the arc tangent of the given argument.
::atan2: Returns the arg tangent of two given arguments.
::cosh: Returns the hyperbolic cosine of the given argument.
::sinh: Returns the hyperbolic sine of the given argument.
::tanh: Returns the hyperbolic tangent of the given argument.
::acosh: Returns the inverse hyperbolic cosine of the given argument.
::asinh: Returns the inverse hyperbolic sine of the given argument.
::atanh: Returns the inverse hyperbolic tangent of the given argument.
::exp: Returns the value of a given value raised to a given power.
::log: Returns the logarithm of a given value in a given base.
::log10: Returns the base 10 logarithm of the given argument.
::log2: Returns the base 2 logarithm of the given argument.
::frexp: Returns the fraction and exponent of the given argument.
::ldexp: Returns the value for a given fraction and exponent.
::cbrt: Returns the cube root of the given argument.
::sqrt: Returns the square root of the given argument.
::erf: Returns the value of the Gauss error function for the given argument.
::erfc: Returns the value of the complementary error function for the given argument.
::gamma: Returns the value of the gamma function for the given argument.
::lgamma: Returns the value of the logarithmic gamma function for the given argument.
::hypot: Returns sqrt(a**2 + b**2) for the given a and b.
OpenSSL::HMAC allows computing Hash-based Message Authentication Code (HMAC). It is a type of message authentication code (MAC) involving a hash function in combination with a key. HMAC can be used to verify the integrity of a message as well as the authenticity.
OpenSSL::HMAC has a similar interface to OpenSSL::Digest.
key = "key" data = "message-to-be-authenticated" mac = OpenSSL::HMAC.hexdigest("SHA256", key, data) #=> "cddb0db23f469c8bf072b21fd837149bd6ace9ab771cceef14c9e517cc93282e"
data1 = File.binread("file1") data2 = File.binread("file2") key = "key" hmac = OpenSSL::HMAC.new(key, 'SHA256') hmac << data1 hmac << data2 mac = hmac.digest
Document-class: OpenSSL::HMAC
OpenSSL::HMAC allows computing Hash-based Message Authentication Code (HMAC). It is a type of message authentication code (MAC) involving a hash function in combination with a key. HMAC can be used to verify the integrity of a message as well as the authenticity.
OpenSSL::HMAC has a similar interface to OpenSSL::Digest.
key = "key" data = "message-to-be-authenticated" mac = OpenSSL::HMAC.hexdigest("SHA256", key, data) #=> "cddb0db23f469c8bf072b21fd837149bd6ace9ab771cceef14c9e517cc93282e"
data1 = File.binread("file1") data2 = File.binread("file2") key = "key" hmac = OpenSSL::HMAC.new(key, 'SHA256') hmac << data1 hmac << data2 mac = hmac.digest
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
Default formatter for log messages.
Parent class for informational (1xx) HTTP response classes.
An informational response indicates that the request was received and understood.
References:
Response class for Non-Authoritative Information responses (status code 203).
The Non-Authoritative Information response indicates that the server is a transforming proxy (such as a Web accelerator) that received a 200 OK response from its origin, and is returning a modified version of the origin’s response.
References:
Response class for Moved Permanently responses (status code 301).
The Moved Permanently response indicates that links or records returning this response should be updated to use the given URL.
References:
Response class for Permanent Redirect responses (status code 308).
This and all future requests should be directed to the given URI.
References:
Response class for Too Many Requests responses (status code 429).
The user has sent too many requests in a given amount of time.
References:
Map from option/keyword string to object with completion.
This represents a magic comment that was encountered during parsing.
Base class for all Gem commands. When creating a new gem command, define initialize, execute, arguments, defaults_str, description and usage (as appropriate). See the above mentioned methods for details.
A very good example to look at is Gem::Commands::ContentsCommand