NLTK Commands and Functions Table

Function/Command/Expression	Description
from nltk.book import *	Loads sample texts and predefined sentence variables from NLTK.
sents()	Lists available texts and sentence samples.
text1	Refers to 'Moby Dick' text loaded from NLTK.
sent1	Preloaded list containing ['Call', 'me', 'Ishmael', '.'].
len(text1)	Counts total words (tokens) in text1.
set(text1)	Extracts unique words (types) from text1.
len(set(text1))	Counts the number of unique words in text1.
sorted(set(text1))	Sorts unique words alphabetically.
text1.count('whale')	Counts occurrences of the word 'whale' in text1.
text1.concordance('monstrous')	Displays words surrounding 'monstrous' in text1.
text1.similar('monstrous')	Finds words used in similar contexts as 'monstrous' in text1.
text2.common_contexts(['monstrous', 'very'])	Finds shared contexts for 'monstrous' and 'very' in text2.
text4.dispersion_plot(['citizens', 'democracy'])	Plots occurrences of words across text4.
text3.generate()	Generates random text in the style of text3.
def lexical_diversity(text): return len(set(text)) / len(text)	Defines a function to compute lexical diversity.
def percentage(count, total): return 100 * count / total	Defines a function to compute percentage.
lexical_diversity(text3)	Computes lexical diversity for text3.
percentage(text4.count('a'), len(text4))	Finds the percentage of 'a' in text4.
FreqDist(text1)	Creates a frequency distribution of words in text1.
fdist1.most_common(50)	Gets the 50 most common words in fdist1.
fdist1.plot(50, cumulative=True)	Plots the cumulative frequency of the 50 most common words.
fdist1.hapaxes()	Finds words that appear only once in text1.
[w for w in set(text1) if len(w) > 15]	Finds words in text1 longer than 15 characters.
sorted(w for w in set(text5) if len(w) > 7 and fdist5[w] > 7)	Finds long words (7+ characters) appearing more than 7 times in text5.
fdist.most_common()	Displays the most common word lengths and their counts.
fdist.max()	Finds the most frequent word length in the text.
fdist.freq(X)	Finds the percentage of words with length X.
fdist.plot(15, cumulative=False)	Plots individual frequencies of word lengths (bar chart).
fdist.plot(15, cumulative=True)	Plots cumulative frequency of word lengths (rising curve).
if len(word) < 5:	Conditional check: Runs block only if word length is less than 5.
for word in sent1:	Loops through each word in sent1.
if word.endswith('l'):	Checks if a word ends with 'l'.
sorted(w for w in set(text2) if 'cie' in w or 'cei' in w)	Finds words in text2 containing 'cie' or 'cei'.
not s.islower()	Checks if a word is not fully lowercase.
s.isupper()	Checks if all characters are uppercase.
s.istitle()	Checks if the first letter is uppercase, rest lowercase (title case).
len(set(word.lower() for word in text1))	Finds unique lowercase words in text1 (removes case sensitivity).
len(word.lower() for word in set(text1))	Creates a generator that applies .lower(), but does not compute unique words properly.
len(set(word.lower() for word in set(text1)))	Corrected version that finds unique words after removing case differences.