Хранение данных

4.5.1.py

# -*- encoding: utf-8 -*-
"""
Постоянное хранилище языковых объектов
"""
import shelve

d = shelve.open(filename) # open -- file may get suffix added by low-level library

d[key] = data   # store data at key (overwrites old data if using an existing key)
data = d[key]   # retrieve a COPY of data at key (raise KeyError if no such key)
del d[key]      # delete data stored at key (raises KeyError if no such key)
flag = d.has_key(key)   # true if the key exists
klist = d.keys() # a list of all existing keys (slow!)

# as d was opened WITHOUT writeback=True, beware:
d['xx'] = range(4)  # this works as expected, but...
d['xx'].append(5)   # *this doesn't!* -- d['xx'] is STILL range(4)!

# having opened d without writeback=True, you need to code carefully:
temp = d['xx']      # extracts the copy
temp.append(5)      # mutates the copy
d['xx'] = temp      # stores the copy right back, to persist it

d=shelve.open(filename,writeback=True) 
d['xx'].append(5)

d.close()       # close it

4.5.2.py

# -*- encoding: utf-8 -*-
"""
Сжатие
"""
import zipfile
import glob, os

# open the zip file for writing, and write stuff to it

file = zipfile.ZipFile("test.zip", "w")

for name in glob.glob("./*"):
    file.write(name, os.path.basename(name), zipfile.ZIP_DEFLATED)

file.close()

# open the file again, to see what's in it

file = zipfile.ZipFile("test.zip", "r")

for name in file.namelist():
    data = file.read(name)
    print name, len(data), repr(data[:10])

for info in file.infolist():
    print info.filename, info.date_time, info.file_size, info.compress_size

4.5.3.py

# -*- encoding: utf-8 -*-
"""
Чтение и запись CSV формата
"""
import csv

reader = csv.reader(open("some.csv", "rb"))
for row in reader:
    print row

#Reading a file with an alternate format:

import csv
reader = csv.reader(open("passwd", "rb"), delimiter=':', quoting=csv.QUOTE_NONE)
for row in reader:
    print row

import csv
writer = csv.writer(open("some.csv", "wb"))
writer.writerows(someiterable)