Returns two arrays, the first containing the elements of enum for which the block evaluates to true, the second containing the rest.
If no block is given, an enumerator is returned instead.
(1..6).partition { |v| v.even? } #=> [[2, 4, 6], [1, 3, 5]]
Returns the first element, or the first n elements, of the enumerable. If the enumerable is empty, the first form returns nil, and the second form returns an empty array.
%w[foo bar baz].first #=> "foo" %w[foo bar baz].first(2) #=> ["foo", "bar"] %w[foo bar baz].first(10) #=> ["foo", "bar", "baz"] [].first #=> nil [].first(10) #=> []
Passes each element of the collection to the given block. The method returns true if the block returns true exactly once. If the block is not given, one? will return true only if exactly one of the collection members is true.
If instead a pattern is supplied, the method returns whether pattern === element for exactly one collection member.
%w{ant bear cat}.one? { |word| word.length == 4 } #=> true %w{ant bear cat}.one? { |word| word.length > 4 } #=> false %w{ant bear cat}.one? { |word| word.length < 4 } #=> false %w{ant bear cat}.one?(/t/) #=> false [ nil, true, 99 ].one? #=> false [ nil, true, false ].one? #=> true [ nil, true, 99 ].one?(Integer) #=> true [].one? #=> false
Passes each element of the collection to the given block. The method returns true if the block never returns true for all elements. If the block is not given, none? will return true only if none of the collection members is true.
If instead a pattern is supplied, the method returns whether pattern === element for none of the collection members.
%w{ant bear cat}.none? { |word| word.length == 5 } #=> true %w{ant bear cat}.none? { |word| word.length >= 4 } #=> false %w{ant bear cat}.none?(/d/) #=> true [1, 3.14, 42].none?(Float) #=> false [].none? #=> true [nil].none? #=> true [nil, false].none? #=> true [nil, false, true].none? #=> false
Computes the cosine of decimal to the specified number of digits of precision, numeric.
If decimal is Infinity or NaN, returns NaN.
BigMath.cos(BigMath.PI(4), 16).to_s #=> "-0.999999999999999999999999999999856613163740061349e0"
Computes the Jacobian of f at x. fx is the value of f at x.
Performs LU decomposition of the n by n matrix a.
Enables coverage measurement.
Generates a hex-encoded version of a given string.
Returns system temporary directory; typically “/tmp”.
Returns a Digest subclass by name
require 'openssl' OpenSSL::Digest("MD5") # => OpenSSL::Digest::MD5 Digest("Foo") # => NameError: wrong constant name Foo
Returns a Digest subclass by name
require 'openssl' OpenSSL::Digest("MD5") # => OpenSSL::Digest::MD5 Digest("Foo") # => NameError: wrong constant name Foo
Returns an inspect() string summarizing the object state.
Return true if the named file exists.
file_name can be an IO object.
“file exists” means that stat() or fstat() system call is successful.
Deprecated method. Don’t use.
Returns true if the named file has the sticky bit set.
file_name can be an IO object.
Initiates garbage collection, unless manually disabled.
This method is defined with keyword arguments that default to true:
def GC.start(full_mark: true, immediate_sweep: true); end
Use full_mark: false to perform a minor GC. Use immediate_sweep: false to defer sweeping (use lazy sweep).
Note: These keyword arguments are implementation and version dependent. They are not guaranteed to be future-compatible, and may be ignored if the underlying implementation does not support them.
The number of times GC occurred.
It returns the number of times GC occurred since the process started.
Returns a Hash containing information about the GC.
The hash includes information about internal statistics about GC such as:
{
:count=>0,
:heap_allocated_pages=>24,
:heap_sorted_length=>24,
:heap_allocatable_pages=>0,
:heap_available_slots=>9783,
:heap_live_slots=>7713,
:heap_free_slots=>2070,
:heap_final_slots=>0,
:heap_marked_slots=>0,
:heap_eden_pages=>24,
:heap_tomb_pages=>0,
:total_allocated_pages=>24,
:total_freed_pages=>0,
:total_allocated_objects=>7796,
:total_freed_objects=>83,
:malloc_increase_bytes=>2389312,
:malloc_increase_bytes_limit=>16777216,
:minor_gc_count=>0,
:major_gc_count=>0,
:remembered_wb_unprotected_objects=>0,
:remembered_wb_unprotected_objects_limit=>0,
:old_objects=>0,
:old_objects_limit=>0,
:oldmalloc_increase_bytes=>2389760,
:oldmalloc_increase_bytes_limit=>16777216
}
The contents of the hash are implementation specific and may be changed in the future.
This method is only expected to work on C Ruby.
Returns the Base64-encoded version of bin. This method complies with RFC 2045. Line feeds are added to every 60 encoded characters.
require 'base64' Base64.encode64("Now is the time for all good coders\nto learn Ruby")
Generates:
Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g UnVieQ==
Returns the Base64-decoded version of str. This method complies with RFC 2045. Characters outside the base alphabet are ignored.
require 'base64' str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' + 'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' + 'ZSB0aHJlZQpBbmQgc28gb24uLi4K' puts Base64.decode64(str)
Generates:
This is line one This is line two This is line three And so on...
Get the default RubyGems API host. This is normally https://rubygems.org.
Set the default RubyGems API host.
Returns the cosine of z, where z is given in radians
CMath.cos(1 + 1i) #=> (0.8337300251311491-0.9888977057628651i)
Returns the hyperbolic cosine of z, where z is given in radians
CMath.cosh(1 + 1i) #=> (0.8337300251311491+0.9888977057628651i)