Method Name:
pickle.dump
Method Signature:
pickle.dump(pythonObject, pickleDestination, pickle_protocol=None, *, fix_imports=True)
Parameters:
pythonObject – The Python Object to be pickled
pickleDestination – File or buffer to which the pickled object will be written
pickle_protocol – One of the constants as defined by the pickle module specifying the pickle protocol version; When None is specified it refers to the default protocol used for the Python version.
fix_imports – When specified, in accordance with the value for the parameter pickle_protocol, the method dump() will decide whether the pickling process should be compatible with Python version 2 or not. The default value is True. This default parameter should be used as a name value pair only.
Return Value:
Returns the reconstructed Python object from the pickle source. The pickle source could be a file or a memory buffer.
Overview:
- The dump() method of the pickle module in Python, converts a Python object hierarchy into a byte stream. This process is also called as serilaization.
- The converted byte stream can be written to a buffer or to a disk file.
- The byte stream of a pickled Python object can converted back to a Python object using the pickle.load() method.
Example:
|
import pickle import io
class Book: title = "" isbn = "" parts = None chapters = None
def __init__(self, title, isbn, parts, chapters): self.title = title self.isbn = isbn self.parts = parts self.chapters = chapters
def identify(self): print("Title of the book: %s"%(self.title)) print("ISBN of the book: %s"%(self.isbn)) print("Parts are:") for part in self.parts: print(part) print("Chapters are:%s"%(self.chapters))
class Part: partName = "" beginChapter = -1 endChapter = -1
def __init__(self, partName, beginChapter, endChapter): self.partName = partName self.beginChapter = beginChapter self.endChapter = endChapter
def __str__(self): stringRep = "%s"%(self.partName) return stringRep
part1 = Part("Part 1", 1, 3) part2 = Part("Part 2", 4, 5) part3 = Part("Part 3", 6, 7)
bookTitle = "Book yet to be written"; bookISBN = "XXX-X-XX-XXXXXX-X"; bookParts = [part1, part2, part3] bookChapters = ["Chapter 1", "Chapter 2", "Chapter 3", "Chapter 4", "Chapter 5", "Chapter 6", "Chapter 7"];
book = Book(bookTitle, bookISBN, bookParts, bookChapters)
pickleBuffer = io.BytesIO() print("Pickling of the object into the memory buffer started") pickle.dump(book,pickleBuffer) print("Pickling of the object into the memory buffer ended") print("Pickled buffer beginning address:") print(pickleBuffer.getbuffer())
print("Unpickling of the object from memory started") unpickledBook = pickle.loads(pickleBuffer.getbuffer()) print("Unpickling of the object from memory ended") print("Printing the attributes of unpickled object") unpickledBook.identify() |
Output:
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Pickling of the object into the memory buffer started Pickling of the object into the memory buffer ended Pickled buffer beginning address: <memory at 0x107d09e88> Unpickling of the object from memory started Unpickling of the object from memory ended Printing the attributes of unpickled object Title of the book: Book yet to be written ISBN of the book: XXX-X-XX-XXXXXX-X Parts are: Part 1 Part 2 Part 3 Chapters are:['Chapter 1', 'Chapter 2', 'Chapter 3', 'Chapter 4', 'Chapter 5', 'Chapter 6', 'Chapter 7'] |