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FreqDist in NLTK



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 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


Usage as bellow:

from nltk import ConditionalFreqDist
cfd = ConditionalFreqDsit(
          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