Wie funktioniert diese Funktion, um Knoten in einem XML -Baum zu durchsuchen? ⇐ Python

[Anonymous]

Ich kann nicht verstehen, was diese Lookup -Funktion tut: < /p>

Code: Select all

def lookup(d, key):
found = False
for child in d:
if found : return child.text
if child.tag == 'key' and child.text == key :
found = True
return None

Dies ist das vollständige Code -Stück. Auch wenn Sie die Datei Library.xml finden müssen, können Sie diesen Link finden, um weitere Kontext zu erhalten: https://www.py4e.com/code3.zip, um die ZIP -Datei herunterzuladen, und dann können Sie zur Datei der BIBLIBORTE.XML -Datei.

Code: Select all

import xml.etree.ElementTree as ET
import sqlite3

conn = sqlite3.connect('trackdb.sqlite')
cur = conn.cursor()

# Make some fresh tables using executescript()
cur.executescript('''
DROP TABLE IF EXISTS Artist;
DROP TABLE IF EXISTS Album;
DROP TABLE IF EXISTS Track;

CREATE TABLE Artist (
id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
name    TEXT UNIQUE
);

CREATE TABLE Album (
id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
artist_id  INTEGER,
title   TEXT UNIQUE
);

CREATE TABLE Track (
id  INTEGER NOT NULL PRIMARY KEY
AUTOINCREMENT UNIQUE,
title TEXT  UNIQUE,
album_id  INTEGER,
len INTEGER, rating INTEGER, count INTEGER
);
''')

fname = input('Enter file name: ')
if ( len(fname) < 1 ) : fname = 'Library.xml'

# Track ID369
# NameAnother One Bites The Dust
# ArtistQueen
def lookup(d, key):
found = False
for child in d:
if found : return child.text
if child.tag == 'key' and child.text == key :
found = True
return None

stuff = ET.parse(fname)
all = stuff.findall('dict/dict/dict')
print('Dict count:', len(all))
for entry in all:
if ( lookup(entry, 'Track ID') is None ) : continue

name = lookup(entry, 'Name')
artist = lookup(entry, 'Artist')
album = lookup(entry, 'Album')
count = lookup(entry, 'Play Count')
rating = lookup(entry, 'Rating')
length = lookup(entry, 'Total Time')

if name is None or artist is None or album is None :
continue

print(name, artist, album, count, rating, length)

cur.execute('''INSERT OR IGNORE INTO Artist (name)
VALUES ( ? )''', ( artist, ) )
cur.execute('SELECT id FROM Artist WHERE name = ? ', (artist, ))
artist_id = cur.fetchone()[0]

cur.execute('''INSERT OR IGNORE INTO Album (title, artist_id)
VALUES ( ?, ? )''', ( album, artist_id ) )
cur.execute('SELECT id FROM Album WHERE title = ? ', (album, ))
album_id = cur.fetchone()[0]

cur.execute('''INSERT OR REPLACE INTO Track
(title, album_id, len, rating, count)
VALUES ( ?, ?, ?, ?, ? )''',
( name, album_id, length, rating, count ) )

conn.commit()