simplegexf 0.1.5

# Simple GEXF
A simple `.gexf` parser / writer for python

**Notice:** This is currently work in progress, and I hope to be able to create documentation in the future when I've settled on the overall structure.

## Motivation:
The official [`pygexf`](https://github.com/paulgirard/pygexf) is poorly maintained and almost not documented at all. I needed a simple abstraction layer for the `XML` format for my project.
This project uses [`xmltodict`](https://github.com/martinblech/xmltodict), which means it's much easier to understand and debug than `pygexf` which uses `lxml`.
This is a tool for those who'd rather spend their time learning about something more interesting and worthwhile than `XML`.


## Usage:

~~~python
from simplegexf import Gexf, Edge

gexf = Gexf('tags.gexf')

try:
graph = gexf.graphs[0]
except IndexError:
graph = gexf.add_graph(defaultedgetype="directed")

# Define Graph attributes
graph.define_attributes([
('description', 'string'),
('count', 'integer'),
])

# Define Edge attributes for Graph
graph.define_attributes([
('relation_type', 'string'),
], _class='edge')

nodes = {node.id: node for node in graph.nodes}

tags = [
{
id: 0,
name: 'Test tag 1',
description: 'This is a test tag',
},
{
id: 1,
name: 'Test tag 2',
description: 'This is a test tag',
parents: [0],
},
{
id: 2,
name: 'Test tag 3',
description: 'This is a test tag',
parents: [0, 1],
}
]

# Create nodes for tags:
for tag in tags:
try:
# See if node exists:
node = nodes[str(tag['id'])]
except KeyError:
# Create a new node:
node = self.graph.add_node(id=str(tag['id']), label=tag['name'])

# Update node:
node.set('viz:size', value=10.0)
node.set('viz:color', r=130, g=130, b=130)

# Update node attributes:
for attr in self.graph.node_attributes.keys():
try:
node.attributes[attr] = tag[attr]
except KeyError:
try:
del node.attributes[attr]
except IndexError:
pass

nodes = {node.id: node for node in graph.nodes}

# Create edges for tags:
for tag in tags:
try:
for parent_id in tag['parents']:
edge = Edge(parent_id, tag['id'])
graph.edges.append(edge)
# Attributes are not available before adding edge to graph
edge.attributes['relation_type'] = 'parents'
except KeyError:
pass

graph.sort_nodes(attr='count', reverse=True)

gexf.write()
~~~