Skip to content
Projects
Groups
Snippets
Help
Loading...
Help
Submit feedback
Contribute to GitLab
Sign in
Toggle navigation
D
dict-trie
Project
Project
Details
Activity
Releases
Cycle Analytics
Repository
Repository
Files
Commits
Branches
Tags
Contributors
Graph
Compare
Charts
Issues
0
Issues
0
List
Board
Labels
Milestones
Merge Requests
0
Merge Requests
0
CI / CD
CI / CD
Pipelines
Jobs
Schedules
Charts
Wiki
Wiki
Snippets
Snippets
Members
Members
Collapse sidebar
Close sidebar
Activity
Graph
Charts
Create a new issue
Jobs
Commits
Issue Boards
Open sidebar
Jeroen F.J. Laros
dict-trie
Commits
c4696045
Commit
c4696045
authored
Apr 30, 2017
by
Jeroen F.J. Laros
Browse files
Options
Browse Files
Download
Email Patches
Plain Diff
Added README.
parent
5f6cdc3a
Changes
1
Hide whitespace changes
Inline
Side-by-side
Showing
1 changed file
with
116 additions
and
0 deletions
+116
-0
README.md
README.md
+116
-0
No files found.
README.md
0 → 100644
View file @
c4696045
# Trie implementation using nested dictionaries
This library provides a
[
trie
](
https://en.wikipedia.org/wiki/Trie
)
implementation using nested dictionaries. Apart from the basic operations, a
number of functions for
*approximate matching*
are implemented.
## Installation
Via
[
pypi
](
https://pypi.python.org/pypi/dict-trie
)
:
pip install dict-trie
From source:
git clone https://git.lumc.nl/j.f.j.laros/dict-trie.git
cd dict-trie
pip install .
## Usage
The library provides the
`Trie`
class. Full documentation can be found
[
here
](
https://git.lumc.nl/j.f.j.laros/dict-trie
)
### Basic operations
Initialisation of the trie is done via the constructor by providing a list of
words.
```
python
>>>
from
dict_trie
import
Trie
>>>
>>>
trie
=
Trie
([
'abc'
,
'te'
,
'test'
])
```
Alternatively, an empty trie can be made to which words can be added with the
`add`
function.
```
python
>>>
trie
=
Trie
()
>>>
trie
.
add
(
'abc'
)
>>>
trie
.
add
(
'te'
)
>>>
trie
.
add
(
'test'
)
```
Membership can be tested with the
`in`
statement.
```
python
>>>
'abc'
in
trie
True
```
Test whether a prefix is present by using the
`has_prefix`
function.
```
python
>>>
trie
.
has_prefix
(
'ab'
)
True
```
Remove a word from the trie with the
`remove`
function. This function returns
`False`
if the word was not in the trie.
```
python
>>>
trie
.
remove
(
'abc'
)
True
>>>
'abc'
in
trie
False
>>>
trie
.
remove
(
'abc'
)
False
```
Iterate over all words in a trie.
```
python
>>>
list
(
trie
)
[
'abc'
,
'te'
,
'test'
]
```
### Approximate matching
A trie can be used to efficiently find a word that is similar to a query word.
This is implemented via a number of functions that search for a word, allowing
a given number of mismatches. These functions are divided in two families, one
using the Hamming distance which only allows substitutions, the other using the
Levenshtein distance which allows substitutions, insertions and deletions.
To find a word that has at most Hamming distance 2 to the word 'abe', the
`hamming`
function is used.
```
python
>>>
trie
=
Trie
([
'abc'
,
'aaa'
,
'ccc'
])
>>>
trie
.
hamming
(
'abe'
,
2
)
'aaa'
```
To get all words that have at most Hamming distance 2 to the word 'abe', the
`all_hamming`
function is used. This function returns a generator.
```
python
>>>
list
(
trie
.
all_hamming
(
'abe'
,
2
))
[
'aaa'
,
'abc'
]
```
In order to find a word that is closest to the query word, the
`best_hamming`
function is used. In this case a word with distance 1 is returned.
```
python
>>>
trie
.
best_hamming
(
'abe'
,
2
)
'abc'
```
The functions
`levenshtein`
,
`all_levenshtein`
and
`best_levenshtein`
are used
in a similar way.
### Other functionalities
A trie can be populated with all words of a fixed length over an alphabet by
using the
`fill`
function.
```
python
>>>
trie
=
Trie
()
>>>
trie
.
fill
((
'a'
,
'b'
),
2
)
>>>
list
(
trie
)
[
'aa'
,
'ab'
,
'ba'
,
'bb'
]
```
The trie data structure can be accessed via the
`root`
member variable.
```
python
>>>
trie
.
root
{
'a'
:
{
'a'
:
{
''
:
{}},
'b'
:
{
''
:
{}}},
'b'
:
{
'a'
:
{
''
:
{}},
'b'
:
{
''
:
{}}}}
>>>
trie
.
root
.
keys
()
[
'a'
,
'b'
]
```
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment