Results for: "remove_const"

IO::EINPROGRESSWaitReadable

exception to wait for reading by EINPROGRESS. see IO.select.

DidYouMean::RequirePathChecker

No documentation available

Net::HTTPServerError

Parent class for server error (5xx) HTTP response classes.

A server error response indicates that the server failed to fulfill a request.

References:

Net::HTTPAlreadyReported

Response class for Already Reported (WebDAV) responses (status code 208).

The Already Reported (WebDAV) response indicates that the server has received the request, and that the members of a DAV binding have already been enumerated in a preceding part of the (multi-status) response, and are not being included again.

References:

Net::HTTPPermanentRedirect

Response class for Permanent Redirect responses (status code 308).

This and all future requests should be directed to the given URI.

References:

Net::HTTPPaymentRequired

Response class for Payment Required responses (status code 402).

Reserved for future use.

References:

Net::HTTPLengthRequired

Response class for Length Required responses (status code 411).

The request did not specify the length of its content, which is required by the requested resource.

References:

Net::HTTPUpgradeRequired

Response class for Upgrade Required responses (status code 426).

The client should switch to the protocol given in the Upgrade header field.

References:

Net::HTTPInternalServerError

Response class for Internal Server Error responses (status code 500).

An unexpected condition was encountered and no more specific message is suitable.

References:

Net::ProtoServerError

No documentation available

OpenURI::HTTPRedirect

Raised on redirection, only occurs when redirect option for HTTP is false.

OpenURI::TooManyRedirects

No documentation available

Prism::MatchRequiredNode

Represents the use of the ‘=>` operator.

foo => bar
^^^^^^^^^^

Prism::RequiredKeywordParameterNode

Represents a required keyword parameter to a method, block, or lambda definition.

def a(b: )
      ^^
end

Prism::RequiredParameterNode

Represents a required parameter to a method, block, or lambda definition.

def a(b)
      ^
end

Resolv::ResolvError

Indicates a failure to resolve a name or address.

Gem::Resolver

Given a set of Gem::Dependency objects as needed and a way to query the set of available specs via set, calculates a set of ActivationRequest objects which indicate all the specs that should be activated to meet the all the requirements.

Complex

A Complex object houses a pair of values, given when the object is created as either rectangular coordinates or polar coordinates.

Rectangular Coordinates

The rectangular coordinates of a complex number are called the real and imaginary parts; see Complex number definition.

You can create a Complex object from rectangular coordinates with:

Note that each of the stored parts may be a an instance one of the classes Complex, Float, Integer, or Rational; they may be retrieved:

The corresponding (computed) polar values may be retrieved:

Polar Coordinates

The polar coordinates of a complex number are called the absolute and argument parts; see Complex polar plane.

In this class, the argument part in expressed radians (not degrees).

You can create a Complex object from polar coordinates with:

Note that each of the stored parts may be a an instance one of the classes Complex, Float, Integer, or Rational; they may be retrieved:

The corresponding (computed) rectangular values may be retrieved:

What’s Here

First, what’s elsewhere:

Here, class Complex has methods for:

Creating Complex Objects

Querying

Comparing

Converting

Performing Complex Arithmetic

Working with JSON

These methods are provided by the JSON gem. To make these methods available:

require 'json/add/complex'

String

A String object has an arbitrary sequence of bytes, typically representing text or binary data. A String object may be created using String::new or as literals.

String objects differ from Symbol objects in that Symbol objects are designed to be used as identifiers, instead of text or data.

You can create a String object explicitly with:

You can convert certain objects to Strings with:

Some String methods modify self. Typically, a method whose name ends with ! modifies self and returns self; often, a similarly named method (without the !) returns a new string.

In general, if both bang and non-bang versions of a method exist, the bang method mutates and the non-bang method does not. However, a method without a bang can also mutate, such as String#replace.

Substitution Methods

These methods perform substitutions:

Each of these methods takes:

The examples in this section mostly use the String#sub and String#gsub methods; the principles illustrated apply to all four substitution methods.

Argument pattern

Argument pattern is commonly a regular expression:

s = 'hello'
s.sub(/[aeiou]/, '*') # => "h*llo"
s.gsub(/[aeiou]/, '*') # => "h*ll*"
s.gsub(/[aeiou]/, '')  # => "hll"
s.sub(/ell/, 'al')     # => "halo"
s.gsub(/xyzzy/, '*')   # => "hello"
'THX1138'.gsub(/\d+/, '00') # => "THX00"

When pattern is a string, all its characters are treated as ordinary characters (not as Regexp special characters):

'THX1138'.gsub('\d+', '00') # => "THX1138"

String replacement

If replacement is a string, that string determines the replacing string that is substituted for the matched text.

Each of the examples above uses a simple string as the replacing string.

String replacement may contain back-references to the pattern’s captures:

See Regexp for details.

Note that within the string replacement, a character combination such as $& is treated as ordinary text, not as a special match variable. However, you may refer to some special match variables using these combinations:

See Regexp for details.

Note that \\ is interpreted as an escape, i.e., a single backslash.

Note also that a string literal consumes backslashes. See string literal for details about string literals.

A back-reference is typically preceded by an additional backslash. For example, if you want to write a back-reference \& in replacement with a double-quoted string literal, you need to write "..\\&..".

If you want to write a non-back-reference string \& in replacement, you need to first escape the backslash to prevent this method from interpreting it as a back-reference, and then you need to escape the backslashes again to prevent a string literal from consuming them: "..\\\\&..".

You may want to use the block form to avoid excessive backslashes.

Hash replacement

If the argument replacement is a hash, and pattern matches one of its keys, the replacing string is the value for that key:

h = {'foo' => 'bar', 'baz' => 'bat'}
'food'.sub('foo', h) # => "bard"

Note that a symbol key does not match:

h = {foo: 'bar', baz: 'bat'}
'food'.sub('foo', h) # => "d"

Block

In the block form, the current match string is passed to the block; the block’s return value becomes the replacing string:

s = '@'
'1234'.gsub(/\d/) { |match| s.succ! } # => "ABCD"

Special match variables such as $1, $2, $`, $&, and $' are set appropriately.

Whitespace in Strings

In the class String, whitespace is defined as a contiguous sequence of characters consisting of any mixture of the following:

Whitespace is relevant for the following methods:

String Slices

A slice of a string is a substring selected by certain criteria.

These instance methods utilize slicing:

Each of the above methods takes arguments that determine the slice to be copied or replaced.

The arguments have several forms. For a string string, the forms are:

string[index]

When a non-negative integer argument index is given, the slice is the 1-character substring found in self at character offset index:

'bar'[0]      # => "b"
'bar'[2]      # => "r"
'bar'[20]     # => nil
'тест'[2]     # => "с"
'こんにちは'[4] # => "は"

When a negative integer index is given, the slice begins at the offset given by counting backward from the end of self:

'bar'[-3]      # => "b"
'bar'[-1]      # => "r"
'bar'[-20]     # => nil

string[start, length]

When non-negative integer arguments start and length are given, the slice begins at character offset start, if it exists, and continues for length characters, if available:

'foo'[0, 2]      # => "fo"
'тест'[1, 2]     # => "ес"
'こんにちは'[2, 2] # => "にち"
# Zero length.
'foo'[2, 0]      # => ""
# Length not entirely available.
'foo'[1, 200]    # => "oo"
# Start out of range.
'foo'[4, 2]      # => nil

Special case: if start equals the length of self, the slice is a new empty string:

'foo'[3, 2]    # => ""
'foo'[3, 200]  # => ""

When a negative start and non-negative length are given, the slice begins by counting backward from the end of self, and continues for length characters, if available:

'foo'[-2, 2]     # => "oo"
'foo'[-2, 200]   # => "oo"
# Start out of range.
'foo'[-4, 2]     # => nil

When a negative length is given, there is no slice:

'foo'[1, -1]   # => nil
'foo'[-2, -1]  # => nil

string[range]

When a Range argument range is given, it creates a substring of string using the indices in range. The slice is then determined as above:

'foo'[0..1]     # => "fo"
'foo'[0, 2]     # => "fo"

'foo'[2...2]    # => ""
'foo'[2, 0]     # => ""

'foo'[1..200]   # => "oo"
'foo'[1, 200]   # => "oo"

'foo'[4..5]     # => nil
'foo'[4, 2]     # => nil

'foo'[-4..-3]   # => nil
'foo'[-4, 2]    # => nil

'foo'[3..4]     # => ""
'foo'[3, 2]     # => ""

'foo'[-2..-1]   # => "oo"
'foo'[-2, 2]    # => "oo"

'foo'[-2..197]  # => "oo"
'foo'[-2, 200]  # => "oo"

string[regexp, capture = 0]

When the Regexp argument regexp is given, and the capture argument is 0, the slice is the first matching substring found in self:

'foo'[/o/]                # => "o"
'foo'[/x/]                # => nil
s = 'hello there'
s[/[aeiou](.)\1/]        # => "ell"
s[/[aeiou](.)\1/, 0]     # => "ell"

If the argument capture is provided and not 0, it should be either a capture group index (integer) or a capture group name (String or Symbol); the slice is the specified capture (see Groups at Regexp and Captures):

s = 'hello there'
s[/[aeiou](.)\1/, 1] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, "non_vowel"] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, :vowel]      # => "e"

If an invalid capture group index is given, there is no slice. If an invalid capture group name is given, IndexError is raised.

string[substring]

When the single String argument substring is given, it returns the substring from self if found, otherwise nil:

'foo'['oo'] # => "oo"
'foo'['xx'] # => nil

What’s Here

First, what’s elsewhere. Class String:

Here, class String provides methods that are useful for:

Methods for Creating a String

Methods for a Frozen/Unfrozen String

Methods for Querying

Counts

Substrings

Encodings

Other

Methods for Comparing

Methods for Modifying a String

Each of these methods modifies self.

Insertion

Substitution

Casing

Encoding

Deletion

Methods for Converting to New String

Each of these methods returns a new String based on self, often just a modified copy of self.

Extension

Encoding

Substitution

Casing

Deletion

Duplication

Methods for Converting to Non-String

Each of these methods converts the contents of self to a non-String.

Characters, Bytes, and Clusters

Splitting

Matching

Numerics

Strings and Symbols

Methods for Iterating

Encoding

An Encoding instance represents a character encoding usable in Ruby. It is defined as a constant under the Encoding namespace. It has a name and, optionally, aliases:

Encoding::US_ASCII.name  # => "US-ASCII"
Encoding::US_ASCII.names # => ["US-ASCII", "ASCII", "ANSI_X3.4-1968", "646"]

A Ruby method that accepts an encoding as an argument will accept:

These are equivalent:

'foo'.encode(Encoding::US_ASCII) # Encoding object.
'foo'.encode('US-ASCII')         # Encoding name.
'foo'.encode('ASCII')            # Encoding alias.

For a full discussion of encodings and their uses, see the Encodings document.

Encoding::ASCII_8BIT is a special-purpose encoding that is usually used for a string of bytes, not a string of characters. But as the name indicates, its characters in the ASCII range are considered as ASCII characters. This is useful when you use other ASCII-compatible encodings.

Exception

Class Exception and its subclasses are used to indicate that an error or other problem has occurred, and may need to be handled. See Exceptions.

An Exception object carries certain information:

Built-In Exception Class Hierarchy

The hierarchy of built-in subclasses of class Exception:

SignalException

Raised when a signal is received.

begin
  Process.kill('HUP',Process.pid)
  sleep # wait for receiver to handle signal sent by Process.kill
rescue SignalException => e
  puts "received Exception #{e}"
end

produces:

received Exception SIGHUP

StandardError

The most standard error types are subclasses of StandardError. A rescue clause without an explicit Exception class will rescue all StandardErrors (and only those).

def foo
  raise "Oups"
end
foo rescue "Hello"   #=> "Hello"

On the other hand:

require 'does/not/exist' rescue "Hi"

raises the exception:

LoadError: no such file to load -- does/not/exist

EncodingError

EncodingError is the base class for encoding errors.

Rational

A rational number can be represented as a pair of integer numbers: a/b (b>0), where a is the numerator and b is the denominator. Integer a equals rational a/1 mathematically.

You can create a Rational object explicitly with:

You can convert certain objects to Rationals with:

Examples

Rational(1)      #=> (1/1)
Rational(2, 3)   #=> (2/3)
Rational(4, -6)  #=> (-2/3) # Reduced.
3.to_r           #=> (3/1)
2/3r             #=> (2/3)

You can also create rational objects from floating-point numbers or strings.

Rational(0.3)    #=> (5404319552844595/18014398509481984)
Rational('0.3')  #=> (3/10)
Rational('2/3')  #=> (2/3)

0.3.to_r         #=> (5404319552844595/18014398509481984)
'0.3'.to_r       #=> (3/10)
'2/3'.to_r       #=> (2/3)
0.3.rationalize  #=> (3/10)

A rational object is an exact number, which helps you to write programs without any rounding errors.

10.times.inject(0) {|t| t + 0.1 }              #=> 0.9999999999999999
10.times.inject(0) {|t| t + Rational('0.1') }  #=> (1/1)

However, when an expression includes an inexact component (numerical value or operation), it will produce an inexact result.

Rational(10) / 3   #=> (10/3)
Rational(10) / 3.0 #=> 3.3333333333333335

Rational(-8) ** Rational(1, 3)
                   #=> (1.0000000000000002+1.7320508075688772i)
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