[Language Processing and Python] 5.3 use the Python dictionary ing word and Its Attributes

Dictionary data type (other programming languages may be called associated arrays or hash arrays)

Index linked list VS Dictionary (omitted)

Python dictionary

# Initializing an empty dictionary

Pos = {}

# Other dictionary usage: pos. keys0, pos. values (), pos. items ()

# Define a non-empty dictionary

>>>pos= {:, : , : , : >>>pos= dict(colorless=,ideas=, sleep=, furiously=)

The first method is usually used. Note that a dictionary key cannot be modified.

Default dictionary

We can use the default dictionary, so that when accessing a key that does not exist, the default value is assigned, rather than the error message is returned.

Set the default data type:

>>>frequency =>>>frequency[] = 4>>>frequency[>>>pos=>>>pos[]= [, >>>pos[

Set the default value:

>>>pos= nltk.defaultdict(: >>>pos[]= >>>pos[>>>pos.items()

[('blog', 'N'), ('colorless', 'ADJ')]

Incrementally update a dictionary

# Incrementally update the dictionary, sorted by value

>>>counts =>>>>>> (word, tag)  brown.tagged_words(categories=+=1>>>counts[22226>>>, , , , , , , , , , , >>> operator >>>sorted(counts.items(), key=itemgetter(1),reverse=, 22226),(, 10845),(, 10648),(, 8336),(, 7313>>>[t  t, c  sorted(counts.items(), key=itemgetter(1),reverse=, , , , , , , , , , , , ...]

# The Implementation of General accumulated tasks and the simpler method provided by nltk. Index ()

>>>anagrams =>>>= >>>anagrams[, , , , , ]

>>>anagrams = nltk.Index((.join(sorted(w)),w)>>>anagrams[, , , , , ]

Inverted dictionary

>>>pos2= nltk.Index((value, key)  (key, value) >>>pos2[, ]

Summary of common methods and dictionary-related habits