kvh / python-suffix-tree

Suffix tree for string searching

Suffix Trees in Python

Based off of Mark Nelson's C++ implementation of Ukkonen's algorithm. Ukkonen's algorithm gives a O(n) + O(k) contruction time for a suffix tree, where n is the length of the string and k is the size of the alphabet of that string. Ukkonen's is an online algorithm, processing the input sequentially and producing a valid suffix tree at each character.

How to use

string = "I need to be searched!"
tree = SuffixTree(string)
index_of_need = tree.find_substring("need")

Usage note

This library is mostly an academic exercise. If you need an efficient library I would recommend a python-wrapped c implementation, such as this one.

python-suffix-tree's Issues

it would be great if you could support unicode strings/files

suffix link question in split_edge function

Hello,

I read your code and Mark Nelson's C++ implementation, and find that you both have the line:
self.nodes[e.dest_node_index].suffix_node = suffix.source_node_index ### need to add node for each edge
in _split_edge function, as you mentioned your implementation is based on Mark Nelson's one,

I don't understand why this line is needed, this line seems that a node have a suffix link pointing to its parent node, and this seams not the suffix link meaning.