How to get the WordNet synset given an offset ID?
Solution 1
As of NLTK 3.2.3, there's a public method for doing this:
wordnet.synset_from_pos_and_offset(pos, offset)
In earlier versions you can use:
wordnet._synset_from_pos_and_offset(pos, offset)
This returns a synset based on it's POS and offest ID. I think this method is only available in NLTK 3.0 but I'm not sure.
Example:
from nltk.corpus import wordnet as wn
wn.synset_from_pos_and_offset('n',4543158)
>> Synset('wagon.n.01')
Solution 2
For NTLK 3.2.3 or newer, please see donners45's answer.
For older versions of NLTK:
There is no built-in method in the NLTK but you could use this:
from nltk.corpus import wordnet
syns = list(wordnet.all_synsets())
offsets_list = [(s.offset(), s) for s in syns]
offsets_dict = dict(offsets_list)
offsets_dict[14204095]
>>> Synset('heatstroke.n.01')
You can then pickle the dictionary and load it whenever you need it.
For NLTK versions prior to 3.0, replace the line
offsets_list = [(s.offset(), s) for s in syns]
with
offsets_list = [(s.offset, s) for s in syns]
since prior to NLTK 3.0 offset
was an attribute instead of a method.
Solution 3
You can use of2ss()
, For example:
from nltk.corpus import wordnet as wn
syn = wn.of2ss('01580050a')
will return
Synset('necessary.a.01')
Solution 4
Other than using NLTK, another option would be to use the .tab file from the Open Multilingual WordNet
http://compling.hss.ntu.edu.sg/omw/ for the Princeton WordNet. Normally i used the recipe below to access wordnet as a dictionary with offset as the key and ;
delimited strings as a values:
# Gets first instance of matching key given a value and a dictionary.
def getKey(dic, value):
return [k for k,v.split(";") in dic.items() if v in value]
# Read Open Multi WN's .tab file
def readWNfile(wnfile, option="ss"):
reader = codecs.open(wnfile, "r", "utf8").readlines()
wn = {}
for l in reader:
if l[0] == "#": continue
if option=="ss":
k = l.split("\t")[0] #ss as key
v = l.split("\t")[2][:-1] #word
else:
v = l.split("\t")[0] #ss as value
k = l.split("\t")[2][:-1] #word as key
try:
temp = wn[k]
wn[k] = temp + ";" + v
except KeyError:
wn[k] = v
return wn
princetonWN = readWNfile('wn-data-eng.tab')
offset = "n#05576222"
offset = offset.split('#')[1]+'-'+ offset.split('#')[0]
print princetonWN.split(";")
print getKey('heatstroke')
Admin
Updated on June 15, 2022Comments
-
Admin almost 2 years
I have a WordNet synset offset (for example
id="n#05576222"
). Given this offset, how can I get the synset using Python? -
Omer over 8 years
offset
is now a method. Try this instead:offsets_dict = {s.offset(): s for s in wn.all_synsets()}
-
Mark Amery over 6 years"There is no built-in method in the NLTK" - there is now! See donners45's answer; this one is obsolete.
-
Daniel Loureiro over 5 yearsThis solution requires a pos tag, while Suzana's doesn't. Can someone explain why the pos tag is necessary for wn.synset_from_pos_and_offset() ?
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vsocrates almost 2 yearsI'm curious about the above as well!