FreqDist in NLTK
2018-02-16
1.FreqDist.
Usage as bellow:
from nltk import FreqDist
fdist = FreqDist([items])
This API FreqDist counting the count of each item in sequence and return the results as a list. But,it is one-dimensional frequency distribution.So you can just apply to one type items.
API of FreqDist
| API | description |
|---|---|
| FreqDist(samples) | create the FreqDsit object |
| fdist.inc(sample) | increment the count of this sample |
| fdist[‘sample’] | return the count of ‘sample’ |
| fdist.freq(‘sample’) | return the frequency of ‘sample’ |
| fdist.N() | total number of samples |
| fdist.keys() | return the samples sorted by decreasing frequency |
| for sample in fdist | iterate samples in order of decreasing frequency |
| fdist.max() | return the sample with max count |
| len(fdist) | return the count of items of freqdist |
| fdist.tabulate() | display a tab of freqdist |
| fdist.plot() | display a figure of freqdist |
| fdist1 < fdist2 | test if samples in fdist1 occur less than in fdist2 |
2.ConditionalFreqDist
Usage as bellow:
from nltk import ConditionalFreqDist
cfd = ConditionalFreqDsit(
(cond,sample)
for cond in [conds] if <xxx>
for sample in [samples] if <xxx>
)
With Conditional Frequency Distribution,you can count multi-dimension(each cond) item.
API of ConditionalFreqDist
| API | description |
|---|---|
| ConditionalFreqDist(cond_sample) | create a ConditionalFreqDist object |
| cfd.conditions() | return alphabetically sorted list of conditions |
| cfd[condition] | return the frequency distribution of this condition |
| cfd[condition][sample] | return the frequency of this sample in this condition |
| cfd.tabulate() | print the tab of cfd |
| cfd.tabulate(samples,conditions) | print the tab of these samples in these conditions |
| cfd.plot() | plot the conditional frequency distribution |
| cfd.plot(samples,conditions) | plot the cfd of these samples in these conditions |
| cfd1 < cfd2 | test if the frequency in cfd1 less than cfd2 |