Results for: "String#[]"

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.

@param [Object] requirement we wish to check @param [Array] possible_binding_requirements array of requirements @param [Array] possibilities array of possibilities the requirements will be used to filter @return [Boolean] whether or not the given requirement is required to filter

out all elements of the array of possibilities.

Load extra data embed into binary format String object.

Reset nil attributes to their default values to make the spec valid

If object is an Array object, returns object.

Otherwise if object responds to :to_ary, calls object.to_ary and returns the result.

Returns nil if object does not respond to :to_ary

Raises an exception unless object.to_ary returns an Array object.

Replaces the content of self with the content of other_array; returns self:

a = [:foo, 'bar', 2]
a.replace(['foo', :bar, 3]) # => ["foo", :bar, 3]

Iterates over array indexes.

When a block given, passes each successive array index to the block; returns self:

a = [:foo, 'bar', 2]
a.each_index {|index|  puts "#{index} #{a[index]}" }

Output:

0 foo
1 bar
2 2

Allows the array to be modified during iteration:

a = [:foo, 'bar', 2]
a.each_index {|index| puts index; a.clear if index > 0 }

Output:

0
1

When no block given, returns a new Enumerator:

a = [:foo, 'bar', 2]
e = a.each_index
e # => #<Enumerator: [:foo, "bar", 2]:each_index>
a1 = e.each {|index|  puts "#{index} #{a[index]}"}

Output:

0 foo
1 bar
2 2

Related: each, reverse_each.

Calls the block with each repeated combination of length n of the elements of self; each combination is an Array; returns self. The order of the combinations is indeterminate.

When a block and a positive Integer argument n are given, calls the block with each n-tuple repeated combination of the elements of self. The number of combinations is (n+1)(n+2)/2.

n = 1:

a = [0, 1, 2]
a.repeated_combination(1) {|combination| p combination }

Output:

[0]
[1]
[2]

n = 2:

a.repeated_combination(2) {|combination| p combination }

Output:

[0, 0]
[0, 1]
[0, 2]
[1, 1]
[1, 2]
[2, 2]

If n is zero, calls the block once with an empty Array.

If n is negative, does not call the block:

a.repeated_combination(-1) {|combination| fail 'Cannot happen' }

Returns a new Enumerator if no block given:

a = [0, 1, 2]
a.repeated_combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>

Using Enumerators, it’s convenient to show the combinations and counts for some values of n:

e = a.repeated_combination(0)
e.size # => 1
e.to_a # => [[]]
e = a.repeated_combination(1)
e.size # => 3
e.to_a # => [[0], [1], [2]]
e = a.repeated_combination(2)
e.size # => 6
e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]

Searches self as described at method bsearch, but returns the index of the found element instead of the element itself.

Returns the list of private methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

module M;    end
class A
  include M
end
class B < A; end
class C < B; end

b = B.new
b.is_a? A          #=> true
b.is_a? B          #=> true
b.is_a? C          #=> false
b.is_a? M          #=> true

b.kind_of? A       #=> true
b.kind_of? B       #=> true
b.kind_of? C       #=> false
b.kind_of? M       #=> true

Returns the number of bits of the value of int.

“Number of bits” means the bit position of the highest bit which is different from the sign bit (where the least significant bit has bit position 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**1000-1).bit_length   #=> 1001
(-2**1000).bit_length     #=> 1000
(-2**1000+1).bit_length   #=> 1000
(-2**12-1).bit_length     #=> 13
(-2**12).bit_length       #=> 12
(-2**12+1).bit_length     #=> 12
-0x101.bit_length         #=> 9
-0x100.bit_length         #=> 8
-0xff.bit_length          #=> 8
-2.bit_length             #=> 1
-1.bit_length             #=> 0
0.bit_length              #=> 0
1.bit_length              #=> 1
0xff.bit_length           #=> 8
0x100.bit_length          #=> 9
(2**12-1).bit_length      #=> 12
(2**12).bit_length        #=> 13
(2**12+1).bit_length      #=> 13
(2**1000-1).bit_length    #=> 1000
(2**1000).bit_length      #=> 1001
(2**1000+1).bit_length    #=> 1001

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

Since int is already an Integer, returns self.

Returns the factorization of self.

See Prime#prime_division for more details.

Iterates the given block over all prime numbers.

See Prime#each for more details.

Invokes the child class’s to_i method to convert num to an integer.

1.0.class          #=> Float
1.0.to_int.class   #=> Integer
1.0.to_i.class     #=> Integer

Returns the float truncated to an Integer.

1.2.to_i      #=> 1
(-1.2).to_i   #=> -1

Note that the limited precision of floating point arithmetic might lead to surprising results:

(0.3 / 0.1).to_i  #=> 2 (!)

to_int is an alias for to_i.

Like backtrace, but returns each line of the execution stack as a Thread::Backtrace::Location. Accepts the same arguments as backtrace.

f = Fiber.new { Fiber.yield }
f.resume
loc = f.backtrace_locations.first
loc.label  #=> "yield"
loc.path   #=> "test.rb"
loc.lineno #=> 1

Returns true if the named file is writable by the real user and group id of this process. See access(3).

Note that some OS-level security features may cause this to return true even though the file is not writable by the real user/group.

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:

• CSV

• Etc.sysconfdir and Etc.systmpdir

• File data read from disk

• File names from Dir

• Integer#chr

• String#inspect and Regexp#inspect

• Strings returned from Readline

• Strings returned from SDBM

• Time#zone

• 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 script encoding (__ENCODING__), not default_internal, is used as the encoding of created strings.

Encoding::default_internal is initialized with -E option or nil otherwise.