File Management in Python - Pickling Data (
Page 4 of 5 )
Using the methods covered in the previous section, it is possible to read strings from files and write strings to files. However, in some situations, you may need to pass other types of data, such as lists, tuples, dictionaries and other objects. In Python, this is possible through a method known as pickling. To pickle data, you would use the "pickle" module included in the standard library.
Let's start by pickling a short list of strings and integers:
import pickle
fileHandle = open ( 'pickleFile.txt', 'w' )
testList = [ 'This', 2, 'is', 1, 'a', 0, 'test.' ]
pickle.dump ( testList, fileHandle )
fileHandle.close()
Unpickling the data is just as easy:
import pickle
fileHandle = open ( 'pickleFile.txt' )
testList = pickle.load ( fileHandle )
fileHandle.cloes()
We can also store more complex data:
import pickle
fileHandle = open ( 'pickleFile.txt', 'w' )
testList = [ 123, { 'Calories' : 190 }, 'Mr. Anderson', [ 1, 2, 7 ] ]
pickle.dump ( testList, fileHandle )
fileHandle.close()
import pickle
fileHandle = open ( 'pickleFile.txt' )
testList = pickle.load ( fileHandle )
fileHandle.close()
As you can see, pickling is extremely easy to do with Python's "pickle" module. Numeous objects may be stored in files with it. You can also use the "cPickle" module if it is availible to you. It's exactly the same as the "pickle" modue, but it's faster:
import cPickle
fileHandle = open ( 'pickleFile.txt', 'w' )
cPickle.dump ( 1776, fileHandle )
fileHandle.close()
| | Discuss File Management in Python | | | | | | | Hello!
I wrote this article with a "less talk and more code" approach. Does... | | | | | | Good article, I like the code-heavy approach. Another module I find useful is... | | | | | | I like the more-code approach. A nice article.
When you're starting out, it's... | | | | | | fileHandle = open ( 'usernames.txt','ab' )
fileHandle.write (raw_input("Please... | | | | | | fileHandle.write ( raw_input ( 'Please enter user name to add: ' ) + '\n' )... | | | | | | Hey.
I am a python newbie, and reading the "File Management" article helped me... | | | | | | following the nice file i/o tutorial here, i have only one remaining quesiton:
how... | | | | | | The article may be good, but it does not explain how to avoid program exit when file... | | | | | | Be consistent with your backslashes, this will solve your problem! | | | | | | thats a more general issue of exception handling, IMHO | | | | | | I get errors when I try to run the first example in - Getting Information on... | | | | | | thanks man! that worked great. (CentOS) | | | | | | for some reason the fileHandle.read() command doesn't work. when i put nothing in... | | | | | | the 'fileHandle' part of fileHandle.read() is the part that specifies the file. dont... | | | | | | hi,
what about:
if os.access(myfile, os.W_OK) ? | | | | | | >>> Post your comment now! | | | | | |
|
 |
