Package nltk :: Module sourcedstring :: Class StringSource

type StringSource

object --+
         |
        StringSource

Known Subclasses:

A description of the location of a string in a document. Each StringSource consists of a document identifier, along with information about the begin and end offsets of each character in the string. These offsets are typically either byte offsets or character offsets. (Note that for unicode strings, byte offsets and character offsets are not the same thing.)

StringSource is an abstract base class. Two concrete subclasses are used depending on the properties of the string whose source is being described:

ConsecutiveCharStringSource describes the source of strings whose characters have consecutive offsets (in particular, byte strings w/ byte offsets; and unicode strings with character offsets).
ContiguousCharStringSource describes the source of strings whose characters are contiguous, but do not necessarily have consecutive offsets (in particular, unicode strings with byte offsets).

Instance Methods

[hide private]

__init__(self, docid, **kwargs)
Create a new StringSource. source code

__getitem__(self, index)
Return a StringSource describing the location where the specified character was found.

source code

__getslice__(self, start, stop)
Return a StringSource describing the location where the specified substring was found.

source code

__len__(self)
Return the length of the string described by this StringSource. source code

__str__(self)

source code

__cmp__(self, other)

source code

__hash__(self)

source code

Static Methods

[hide private]

__new__(cls, docid, *args, **kwargs)

source code

Instance Variables

[hide private]

begin
The document offset where the string begins.

docid
An identifier (such as a filename) that specifies which document contains the string.

end
The document offset where the string ends.

offsets
A list of offsets specifying the location of each character in the document.

Method Details

[hide private]

new(cls, docid, *args, **kwargs)
Static Method

source code

Overrides: object.__new__: (inherited documentation)

init(self, docid, **kwargs)
(Constructor)

source code

Create a new StringSource. When the StringSource constructor is called directly, it automatically delegates to one of its two subclasses:

If begin and end are specified, then a ConsecutiveCharStringSource is returned.
If offsets is specified, then a ContiguousCharStringSource is returned.

In both cases, the arguments must be specified as keyword arguments (not positional arguments).

Overrides: object.__init__

getitem(self, index)
(Indexing operator)

source code

Return a StringSource describing the location where the specified character was found. In particular, if s is the string that this source describes, then return a StringSource describing the location of s[index].

Raises:

IndexError - If index is out of range.

getslice(self, start, stop)
(Slicling operator)

source code

Return a StringSource describing the location where the specified substring was found. In particular, if s is the string that this source describes, then return a StringSource describing the location of s[start:stop].

Decorators:

@abstract

Note: This method is abstract.

len(self)
(Length operator)

source code

Return the length of the string described by this StringSource. Note that this may not be equal to self.end-self.begin for unicode strings described using byte offsets.

Decorators:

@abstract

Note: This method is abstract.

str(self)
(Informal representation operator)

source code

Overrides: object.__str__: (inherited documentation)

hash(self)
(Hashing function)

source code

Overrides: object.__hash__: (inherited documentation)

Instance Variable Details

[hide private]

begin

The document offset where the string begins. (I.e., the offset of the first character in the string.) source.begin is always equal to source.offsets[0].

end

The document offset where the string ends. (For character offsets, one plus the offset of the last character; for byte offsets, one plus the offset of the last byte that encodes the last character). source.end is always equal to source.offsets[-1].

offsets

A list of offsets specifying the location of each character in the document. The ith character of the string begins at offset offsets[i] and ends at offset offsets[i+1]. The length of the offsets list is one greater than the list of the string described by this StringSource.

type StringSource

__new__(cls, docid, *args, **kwargs) Static Method

__init__(self, docid, **kwargs) (Constructor)

__getitem__(self, index) (Indexing operator)

__getslice__(self, start, stop) (Slicling operator)

__len__(self) (Length operator)

__str__(self) (Informal representation operator)

__hash__(self) (Hashing function)

begin

end

offsets

new(cls, docid, *args, **kwargs)
Static Method

init(self, docid, **kwargs)
(Constructor)

getitem(self, index)
(Indexing operator)

getslice(self, start, stop)
(Slicling operator)

len(self)
(Length operator)

str(self)
(Informal representation operator)

hash(self)
(Hashing function)