Download our e-book of Introduction To Python
Related Blog
Matplotlib - Subplot2grid() FunctionDiscuss Microsoft Cognitive ToolkitMatplotlib - Working with ImagesMatplotlib - PyLab moduleMatplotlib - Working With TextMatplotlib - Setting Ticks and Tick LabelsCNTK - Creating First Neural NetworkMatplotlib - MultiplotsMatplotlib - Quiver PlotPython - Chunks and Chinks View More
Top Discussion
How can I write Python code to change a date string from "mm/dd/yy hh: mm" format to "YYYY-MM-DD HH: mm" format? Which sorting technique is used by sort() and sorted() functions of python? How to use Enum in python? Can you please help me with this error? I was just selecting some random columns from the diabetes dataset of sklearn. Decision tree is a classification algo...How can it be applied to load diabetes dataset which has DV continuous Objects in Python are mutable or immutable? How can unclassified data in a dataset be effectively managed when utilizing a decision tree-based classification model in Python? How to leave/exit/deactivate a Python virtualenvironment Join Discussion
Top Courses
Webinars
Python Data Persistence - Marshal Module
Neha Kumawat
3 years ago
Marshal module is used by Python itself for Python’s internal object serialization to support reading/writing operations on compiled versions of Python modules (.pyc files). Marshal module's Object serialization features are the same as the pickle module.
The data format used by the marshal module is not compatible with Python versions. Therefore, a compiled Python script (.pyc file) of one version will probably not work for another.
For reading and writing marshalled objects from / to file marshal module defined load() and dump() functions.
Recommended Blogs for you : Why pickling is important?
dump() Function
This function is used to writes a byte representation of a Python object to a file with write permission.
Syntax :
marshal.dump(value, file[, version])
Where ,
- value must be a supported type.
- The file must be a writable binary file.
- version argument indicates the data format
If the value has an unsupported type then a ValueError exception is raised.
load() Function
This function reads one value(byte data) from an open binary file and returns the converted Python object.
Syntax :
marshal.load(file)
Where,
- The file must be a readable binary file.
If no value is read. then EOFError, ValueError or TypeError is raised.
compile() Function
The code uses the built-in compile() function which returns the python code object from the source
Syntax :
compile(source, filename, mode, flag, dont_inherit, optimize)
Where,
- source -. can be a String, a Bytes object, or an AST object.
- filename - The name of the file
- mode - exec or eval or single.
- flag (optional) - How to compile the source object. Default 0.
- dont_inherit (optional) - How to compile the source object. Default False.
- optimize (optional) - optimization level of compiler. Default -1.
The mode parameter is:
- ‘exec’ if the source contains a sequence of statements,
- ‘eval’ if there is a single expression
- ‘single’ if it contains a single interactive statement.
The compile code object is stored in a .pyc file using dump() function.
The following program shows the use of dump() and load() functions.
import marshal
script = """
a=10
b=20
print ('addition=',a+b)
"""
code = compile(script, "script", "exec")
f=open("a.pyc","wb")
marshal.dump(code, f)
f.close()
The load() function is used to deserialize the object from .pyc file. Since it returns a python code object, it can be run using exec() function or another built-in function.
import marshal
f=open("a.pyc","rb")
data=marshal.load(f)
exec (data)
Recommended Course for you :
Recommended Blogs for you :