Sets the (group) real and/or effective group IDs of the current process to rid and eid, respectively. A value of -1 for either means to leave that ID unchanged. Not available on all platforms.
Sets the (user) real, effective, and saved user IDs of the current process to rid, eid, and sid respectively. A value of -1 for any value means to leave that ID unchanged. Not available on all platforms.
Sets the (group) real, effective, and saved user IDs of the current process to rid, eid, and sid respectively. A value of -1 for any value means to leave that ID unchanged. Not available on all platforms.
Returns whether this dependency, which has no possible matching specifications, can safely be ignored.
@param [Object] dependency @return [Boolean] whether this dependency can safely be skipped.
Load extra data embed into binary format String object.
Reset nil attributes to their default values to make the spec valid
Tries to convert obj into an array, using to_ary method. Returns the converted array or nil if obj cannot be converted for any reason. This method can be used to check if an argument is an array.
Array.try_convert([1]) #=> [1] Array.try_convert("1") #=> nil if tmp = Array.try_convert(arg) # the argument is an array elsif tmp = String.try_convert(arg) # the argument is a string end
Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.
a = [ "a", "b", "c", "d", "e" ] a.replace([ "x", "y", "z" ]) #=> ["x", "y", "z"] a #=> ["x", "y", "z"]
Same as Array#each, but passes the index of the element instead of the element itself.
An Enumerator is returned if no block is given.
a = [ "a", "b", "c" ] a.each_index {|x| print x, " -- " }
produces:
0 -- 1 -- 2 --
When invoked with a block, yields all repeated combinations of length n of elements from the array and then returns the array itself.
The implementation makes no guarantees about the order in which the repeated combinations are yielded.
If no block is given, an Enumerator is returned instead.
Examples:
a = [1, 2, 3] a.repeated_combination(1).to_a #=> [[1], [2], [3]] a.repeated_combination(2).to_a #=> [[1,1],[1,2],[1,3],[2,2],[2,3],[3,3]] a.repeated_combination(3).to_a #=> [[1,1,1],[1,1,2],[1,1,3],[1,2,2],[1,2,3], # [1,3,3],[2,2,2],[2,2,3],[2,3,3],[3,3,3]] a.repeated_combination(4).to_a #=> [[1,1,1,1],[1,1,1,2],[1,1,1,3],[1,1,2,2],[1,1,2,3], # [1,1,3,3],[1,2,2,2],[1,2,2,3],[1,2,3,3],[1,3,3,3], # [2,2,2,2],[2,2,2,3],[2,2,3,3],[2,3,3,3],[3,3,3,3]] a.repeated_combination(0).to_a #=> [[]] # one combination of length 0
By using binary search, finds an index of a value from this array which meets the given condition in O(log n) where n is the size of the array.
It supports two modes, depending on the nature of the block and they are exactly the same as in the case of bsearch method with the only difference being that this method returns the index of the element instead of the element itself. For more details consult the documentation for bsearch.
Returns the number of bits of the value of int.
“the number of bits” means that the bit position of the highest bit which is different to the sign bit. (The bit position of the bit 2**n is n+1.) If there is no such bit (zero or minus one), zero is returned.
I.e. This method returns ceil(log2(int < 0 ? -int : int+1)).
(-2**10000-1).bit_length #=> 10001 (-2**10000).bit_length #=> 10000 (-2**10000+1).bit_length #=> 10000 (-2**1000-1).bit_length #=> 1001 (-2**1000).bit_length #=> 1000 (-2**1000+1).bit_length #=> 1000 (2**1000-1).bit_length #=> 1000 (2**1000).bit_length #=> 1001 (2**1000+1).bit_length #=> 1001 (2**10000-1).bit_length #=> 10000 (2**10000).bit_length #=> 10001 (2**10000+1).bit_length #=> 10001
This method can be used to detect overflow in Array#pack as follows.
if n.bit_length < 32 [n].pack("l") # no overflow else raise "overflow" end
Numerics are immutable values, which should not be copied.
Any attempt to use this method on a Numeric will raise a TypeError.
Invokes the child class’s to_i method to convert num to an integer.
1.0.class => Float 1.0.to_int.class => Fixnum 1.0.to_i.class => Fixnum
Returns true if the named file is writable by the real user and group id of this process. See access(3)
If file_name is writable by others, returns an integer representing the file permission bits of file_name. Returns nil otherwise. The meaning of the bits is platform dependent; on Unix systems, see stat(2).
file_name can be an IO object.
File.world_writable?("/tmp") #=> 511 m = File.world_writable?("/tmp") sprintf("%o", m) #=> "777"
Returns the list of available encoding names.
Encoding.name_list
#=> ["US-ASCII", "ASCII-8BIT", "UTF-8",
"ISO-8859-1", "Shift_JIS", "EUC-JP",
"Windows-31J",
"BINARY", "CP932", "eucJP"]
Returns default internal encoding. Strings will be transcoded to the default internal encoding in the following places if the default internal encoding is not nil:
File data read from disk
Strings returned from Readline
Strings returned from SDBM
Values from ENV
Values in ARGV including $PROGRAM_NAME
Additionally String#encode and String#encode! use the default internal encoding if no encoding is given.
The locale encoding (__ENCODING__), not default_internal, is used as the encoding of created strings.
Encoding::default_internal is initialized by the source file’s internal_encoding or -E option.
Sets default internal encoding or removes default internal encoding when passed nil. You should not set Encoding::default_internal in ruby code as strings created before changing the value may have a different encoding from strings created after the change. Instead you should use ruby -E to invoke ruby with the correct default_internal.
See Encoding::default_internal for information on how the default internal encoding is used.
Iterates the given block for each element with an index, which starts from offset. If no block is given, returns a new Enumerator that includes the index, starting from offset
offset
the starting index to use