nltk.treeprettyprinter.TreePrettyPrinter

class documentation

class TreePrettyPrinter(object): (source)

Constructor: TreePrettyPrinter(tree, sentence, highlight)

Pretty-print a tree in text format, either as ASCII or Unicode. The tree can be a normal tree, or discontinuous.

TreePrettyPrinter(tree, sentence=None, highlight=()) creates an object from which different visualizations can be created.

>>> from nltk.tree import Tree
>>> tree = Tree.fromstring('(S (NP Mary) (VP walks))')
>>> print(TreePrettyPrinter(tree).text())
... # doctest: +NORMALIZE_WHITESPACE
      S
  ____|____
 NP        VP
 |         |
Mary     walks

Parameters
tree	a Tree object.
sentence	a list of words (strings). If `sentence` is given, `tree` must contain integers as leaves, which are taken as indices in `sentence`. Using this you can display a discontinuous tree.
highlight	Optionally, a sequence of Tree objects in `tree` which should be highlighted. Has the effect of only applying colors to nodes in this sequence (nodes should be given as Tree objects, terminals as indices).

Static Method	`nodecoords`	Produce coordinates of nodes on a grid.
Method	`__init__`	Undocumented
Method	`__repr__`	Undocumented
Method	`__str__`	Undocumented
Method	`svg`	No summary
Method	`text`	No summary
Instance Variable	`coords`	Undocumented
Instance Variable	`edges`	Undocumented
Instance Variable	`highlight`	Undocumented
Instance Variable	`nodes`	Undocumented

@staticmethod
def nodecoords(tree, sentence, highlight): (source) ¶

Produce coordinates of nodes on a grid.

Objective:

Produce coordinates for a non-overlapping placement of nodes and

horizontal lines.
Order edges so that crossing edges cross a minimal number of previous

horizontal lines (never vertical lines).

Approach:

bottom up level order traversal (start at terminals)
at each level, identify nodes which cannot be on the same row
identify nodes which cannot be in the same column
place nodes into a grid at (row, column)
order child-parent edges with crossing edges last

Coordinates are (row, column); the origin (0, 0) is at the top left; the root node is on row 0. Coordinates do not consider the size of a node (which depends on font, &c), so the width of a column of the grid should be automatically determined by the element with the greatest width in that column. Alternatively, the integer coordinates could be converted to coordinates in which the distances between adjacent nodes are non-uniform.

Produces tuple (nodes, coords, edges, highlighted) where:

nodes[id]: Tree object for the node with this integer id
coords[id]: (n, m) coordinate where to draw node with id in the grid
edges[id]: parent id of node with this id (ordered dictionary)
highlighted: set of ids that should be highlighted

def __init__(self, tree, sentence=None, highlight=()): (source) ¶

Undocumented

def __repr__(self): (source) ¶

Undocumented

def __str__(self): (source) ¶

Undocumented

def svg(self, nodecolor='blue', leafcolor='red', funccolor='green'): (source) ¶

Returns
SVG representation of a tree.

def text(self, nodedist=1, unicodelines=False, html=False, ansi=False, nodecolor='blue', leafcolor='red', funccolor='green', abbreviate=None, maxwidth=16): (source) ¶

Parameters
nodedist	Undocumented
unicodelines	whether to use Unicode line drawing characters instead of plain (7-bit) ASCII.
html	whether to wrap output in html code (default plain text).
ansi	whether to produce colors with ANSI escape sequences (only effective when html==False).
nodecolor	Undocumented
leafcolor	Undocumented
funccolor	Undocumented
abbreviate	if True, abbreviate labels longer than 5 characters. If integer, abbreviate labels longer than `abbr` characters.
maxwidth	maximum number of characters before a label starts to wrap; pass None to disable.
leafcolor, nodecolor	specify colors of leaves and phrasal nodes; effective when either html or ansi is True.
Returns
ASCII art for a discontinuous tree.

coords = (source) ¶

Undocumented

edges = (source) ¶

Undocumented

highlight = (source) ¶

Undocumented

nodes = (source) ¶

Undocumented