pattern-it

# pattern.it

The pattern.it module contains a fast part-of-speech tagger for Italian (identifies nouns, adjectives, verbs, etc. in a sentence) and tools for Italian verb conjugation and noun singularization & pluralization.

It can be used by itself or with other pattern modules: web | db | en | search | vector | graph.

## Documentation

The functions in this module take the same parameters and return the same values as their counterparts in pattern.en. Refer to the documentation there for more details.

### Gender

Italian nouns and adjectives inflect according to gender. The gender() function predicts the gender (MALE, FEMALE, PLURAL) of a given noun with about 92% accuracy:

    >>> from pattern.it import gender, MALE, FEMALE, PLURAL
    >>> print gender('gatti')

    (MALE, PLURAL)

### Article

The article() function returns the article (INDEFINITE or DEFINITE) inflected by gender (e.g., il gatto → i gatti).

    >>> from pattern.it import article, DEFINITE, MALE, PLURAL
    >>> print article('gatti', DEFINITE, gender=(MALE, PLURAL))

    i

### Noun singularization & pluralization

For Italian nouns there is singularize() and pluralize(). The implementation is slightly less robust than the English version (accuracy 84% for singularization and 93% for pluralization).

    >>> from pattern.it import singularize, pluralize
    >>>
    >>> print singularize('gatti')
    >>> print pluralize('gatto')

    gatto
    gatti

### Verb conjugation

For Italian verbs there is conjugate(), lemma(), lexeme() and tenses(). The lexicon for verb conjugation contains about 1,250 common Italian verbs, mined from Wiktionary. For unknown verbs it will fall back to a rule-based approach with an accuracy of about 86%.

Italian verbs have more tenses than English verbs. In particular, the plural differs for each person, and there are additional forms for the FUTURE tense, the IMPERATIVE, CONDITIONAL and SUBJUNCTIVE mood and the PERFECTIVE aspect:

    >>> from pattern.it import conjugate
    >>> from pattern.it import INFINITIVE, PRESENT, PAST, SG, SUBJUNCTIVE, PERFECTIVE
    >>>
    >>> print conjugate('sono', INFINITIVE)
    >>> print conjugate('sono', PRESENT, 1, SG, mood=SUBJUNCTIVE)
    >>> print conjugate('sono', PAST, 3, SG)
    >>> print conjugate('sono', PAST, 3, SG, aspect=PERFECTIVE)

    essere
    sia
    era
    fu

For PAST tense + PERFECTIVE aspect we can also use PRETERITE (passato remoto) For PAST tense + IMPERFECTIVE aspect we can also use IMPERFECT (imperfetto).

    >>> from pattern.it import conjugate
    >>> from pattern.it import IMPERFECT, PRETERITE
    >>>
    >>> print conjugate('sono', IMPERFECT, 3, SG)
    >>> print conjugate('sono', PRETERITE, 3, SG)

    era
    fu

The conjugate() function takes the following optional parameters:

Tense | Person | Number | Mood | Aspect | Alias | Example
INFINITVE | None | None | None | None | "inf" | essere
PRESENT | 1 | SG | INDICATIVE | IMPERFECTIVE | "1sg" | io sono
PRESENT | 2 | SG | INDICATIVE | IMPERFECTIVE | "2sg" | tu sei
PRESENT | 3 | SG | INDICATIVE | IMPERFECTIVE | "3sg" | lui è
PRESENT | 1 | PL | INDICATIVE | IMPERFECTIVE | "1pl" | noi siamo
PRESENT | 2 | PL | INDICATIVE | IMPERFECTIVE | "2pl" | voi siete
PRESENT | 3 | PL | INDICATIVE | IMPERFECTIVE | "3pl" | loro sono
PRESENT | None | None | INDICATIVE | PROGRESSIVE | "part" | essendo
PRESENT | 2 | SG | IMPERATIVE | IMPERFECTIVE | "2sg!" | sii
PRESENT | 3 | SG | IMPERATIVE | IMPERFECTIVE | "3sg!" | sia
PRESENT | 1 | PL | IMPERATIVE | IMPERFECTIVE | "1pl!" | siamo
PRESENT | 2 | PL | IMPERATIVE | IMPERFECTIVE | "2pl!" | siate
PRESENT | 3 | PL | IMPERATIVE | IMPERFECTIVE | "3pl!" | siano
PRESENT | 1 | SG | SUBJUNCTIVE | IMPERFECTIVE | "1sg?" | io sia
PRESENT | 2 | SG | SUBJUNCTIVE | IMPERFECTIVE | "2sg?" | tu sia
PRESENT | 3 | SG | SUBJUNCTIVE | IMPERFECTIVE | "3sg?" | lui sia
PRESENT | 1 | PL | SUBJUNCTIVE | IMPERFECTIVE | "1pl?" | noi siamo
PRESENT | 2 | PL | SUBJUNCTIVE | IMPERFECTIVE | "2pl?" | voi siate
PRESENT | 3 | PL | SUBJUNCTIVE | IMPERFECTIVE | "3pl?" | loro siano
PAST | 1 | SG | INDICATIVE | IMPERFECTIVE | "1sgp" | io ero
PAST | 2 | SG | INDICATIVE | IMPERFECTIVE | "2sgp" | tu eri
PAST | 3 | SG | INDICATIVE | IMPERFECTIVE | "3sgp" | lui era
PAST | 1 | PL | INDICATIVE | IMPERFECTIVE | "1ppl" | noi eravamo
PAST | 2 | PL | INDICATIVE | IMPERFECTIVE | "2ppl" | voi eravate
PAST | 3 | PL | INDICATIVE | IMPERFECTIVE | "3ppl" | loro erano
PAST | None | None | INDICATIVE | PROGRESSIVE | "ppart" | stato
PAST | 1 | SG | INDICATIVE | PERFECTIVE | "1sgp+" | io fui
PAST | 2 | SG | INDICATIVE | PERFECTIVE | "2sgp+" | tu fosti
PAST | 3 | SG | INDICATIVE | PERFECTIVE | "3sgp+" | lui fu
PAST | 1 | PL | INDICATIVE | PERFECTIVE | "1ppl+" | noi fummo
PAST | 2 | PL | INDICATIVE | PERFECTIVE | "2ppl+" | voi foste
PAST | 3 | PL | INDICATIVE | PERFECTIVE | "3ppl+" | loro furono
PAST | 1 | SG | SUBJUNCTIVE | IMPERFECTIVE | "1sgp?" | io fossi
PAST | 2 | SG | SUBJUNCTIVE | IMPERFECTIVE | "2sgp?" | tu fossi
PAST | 3 | SG | SUBJUNCTIVE | IMPERFECTIVE | "3sgp?" | lui fosse
PAST | 1 | PL | SUBJUNCTIVE | IMPERFECTIVE | "1ppl?" | noi fossimo
PAST | 2 | PL | SUBJUNCTIVE | IMPERFECTIVE | "2ppl?" | voi foste
PAST | 3 | PL | SUBJUNCTIVE | IMPERFECTIVE | "3ppl?" | loro fossero
FUTURE | 1 | SG | INDICATIVE | IMPERFECTIVE | "1sgf" | io sarò
FUTURE | 2 | SG | INDICATIVE | IMPERFECTIVE | "2sgf" | tu sarai
FUTURE | 3 | SG | INDICATIVE | IMPERFECTIVE | "3sgf" | lui sarà
FUTURE | 1 | PL | INDICATIVE | IMPERFECTIVE | "1plf" | noi saremo
FUTURE | 2 | PL | INDICATIVE | IMPERFECTIVE | "2plf" | voi sarete
FUTURE | 3 | PL | INDICATIVE | IMPERFECTIVE | "3plf" | loro saranno
CONDITIONAL | 1 | SG | INDICATIVE | IMPERFECTIVE | "1sg->" | io sarei
CONDITIONAL | 2 | SG | INDICATIVE | IMPERFECTIVE | "2sg->" | tu saresti
CONDITIONAL | 3 | SG | INDICATIVE | IMPERFECTIVE | "3sg->" | lui sarebbe
CONDITIONAL | 1 | PL | INDICATIVE | IMPERFECTIVE | "1pl->" | noi saremmo
CONDITIONAL | 2 | PL | INDICATIVE | IMPERFECTIVE | "2pl->" | voi sareste
CONDITIONAL | 3 | PL | INDICATIVE | IMPERFECTIVE | "3pl->" | loro sarebbero

Instead of optional parameters, a single short alias, or PARTICIPLE or PAST+PARTICIPLE can also be given. With no parameters, the infinitive form of the verb is returned.

### Attributive & predicative adjectives

Italian adjectives inflect with suffixes -o → -i (masculine) and -a → -e (feminine), with some exceptions (e.g., grande → i grandi felini). You can get the base form with the predicative() function. A statistical approach is used with an accuracy of 88%.

    >>> from pattern.it import attributive
    >>> print predicative('grandi')

    grande

### Parser

For parsing there is parse(), parsetree() and split(). The parse() function annotates words in the given string with their part-of-speech tags (e.g., NN for nouns and VB for verbs). The parsetree() function takes a string and returns a tree of nested objects (Text → Sentence → Chunk → Word). The split() function takes the output of parse() and returns a Text. See the pattern.en documentation (here) how to manipulate Text objects.

    >>> from pattern.it import parse, split
    >>>
    >>> s = parse('Il gatto nero faceva le fusa.')
    >>> for sentence in split(s):
    >>>     print sentence

    Sentence('Il/DT/B-NP/O gatto/NN/I-NP/O nero/JJ/I-NP/O'
             'faceva/VB/B-VP/O'
             'le/DT/B-NP/O fusa/NN/I-NP/O ././O/O')

The parser is mined from Wiktionary. The accuracy is around 92%.

### Sentiment analysis

There's no sentiment() function for Italian yet.