Functional Python Programming

Chapter 15

data = [Pair(2,3), Pair(5,7)]

serialize_csv(""test"", data)

b'x,y\r\n2,3\r\n5,7\r\n'

""""""

buffer= io.StringIO()

wtr= csv.DictWriter(buffer, Pair._fields)

wtr.writeheader()

wtr.writerows(r._asdict() for r in data)

return buffer.getvalue()

The CSV module's readers and writers are a mixture of imperative and functional
elements. We must create the writer, and properly create headings in a strict
sequence. We've used the _fields attribute of the Pair namedtuple to determine
the column headings for the writer.

The writerows() method of the writer will accept a lazy generator function.
In this case, we used the _asdict() method of each Pair object to return a
dictionary suitable for use with the CSV writer.

Serializing data into XML

We'll look at one approach to XML serialization using the built-in libraries. This will
build a document from individual tags. A common alternative approach is to use
Python introspection to examine and map Python objects and class names to XML
tags and attributes.

Here's our XML serialization:

import xml.etree.ElementTree as XML

def serialize_xml(series, data):

""""""

data = [Pair(2,3), Pair(5,7)]

serialize_xml(""test"", data)

b'<series name=""test"">235

""""""

doc= XML.Element(""series"", name=series)

for row in data:

row_xml= XML.SubElement(doc, ""row"")

x= XML.SubElement(row_xml, ""x"")