function summary of nltk in python

1. re.findall(regexp,word):find the characters in word by the pattern "regexp"
2. nltk.regexp_tokenize(text,pattern): find the characters in text by the pattern "pattern" 
3. re.split(r",",string):divide the string by ","
4. text.concordance("hello"):find "hello" in text and output the at line 
5. text.similar("hello"):find the similar attribute like "hello" and output the word 
6. sorted(word_list):sort the words in word_list
7. set(word_list):delete the words 
8. word_list.append("hello"):add "hello" to the word_list
9. len(word_list):count the words number 
10. word_list.count("hello"):count the number of "hello" in the word_list  
11. word_list.index("hello"):return the index of the first "hello" in the word_list
12. fdist = FreqDist(word_list):calculate the words number and create the word:number pairs 
13. nltk.***.words("fileid"):get the content of "fileid" in type of words
14. ***.fileids():return all the fileid in the language library "***"
15. text = nltk.Text(wordlist):convert the wordlist into the text mode 
16. PlaintextCorpusReader(path,".*"):get all the file content in the path
17. nltk.word_tokenize(string):divide the string into wordlist
18. nltk.sent_tokenize(string):divide the string into sent
19. the for used in nltk
    for item in s : traverse elements in s
    for item in set(s) :  traverse elements in s and no repeat
    for item in sort(s) ; traverse elements in s by order
    for item in reversed(s) : traverse elements in s by reversed order
    for item in set(s).difference(t) : traverse elements in s but not in t
    for item in random.shuffle(s) : traverse elements in s by random order