DiskDict

Description

DiskDict is a file based module which stores data as key, value pairs like a python dictionary. DiskDict stores the data on the disk unlike python dictionary which stores data in the RAM.

Installation

Prerequisites: Python

$ sudo pip install diskdict

Quick Example

>>> from diskdict import DiskDict

# Initiate the diskdict with the path
>>> dd = DiskDict('/tmp/diskdict')

# Storing the data into diskdict
>>> dd['deepcompute'] = 1
>>> dd['deeporg'] = 2
>>> dd[1] = 5

# Get the values regarding keys from diskdict
>>> print(dd.get('deepcompute'))
1

>>> print(dd['deepcompute'])
1

# Get key, value pairs in tuple format from diskdict
>>> next(dd.items())
('deeporg', 2)

>>> for item in dd.items():
...     print(item)
...
('deeporg', 2)
('deepcompute', 1)
(1, 5)

# Get the keys from diskdict
>>> next(dd.keys())
deeporg

>>> for key in dd.keys():
...     print(key)
...
deeporg
deepcompute
1

# Get the values from diskdict
>>> next(dd.values())
2

>>> for value in dd.values():
...     print(value)
...
2
1
5

# closing the file
>>> dd.close()

Interactive console

$ diskdict interact <input_file>

QuickExample

$ diskdict interact /tmp/disk.dict
DiskDict Console
>>> dd['dc']=1
>>> dd.get('dc')
1

Static String to Int map

diskdict uses cmph and mmap to build static string to integer map. We have to provide the byte strings initially. diskdict builds respective index for each key.

Example

from diskdict import StaticStringIndexDict

l = [b'india', b'usa', b'japan', b'china']
s = StaticStringIndexDict(path='/data/map', keys=l)

print(s[b'japan'])

s.close()

Above example builds the map in the location of /data/map. We don't have to provide the byte strings from second time onwards.

from diskdict import StaticStringIndexDict

s = StaticStringIndexDict(path='/data/map')
print(s[b'japan'])

s.close()

Running Tests

$ python setup.py test