docs/usage/display_system/basic.md - zeppelin - Git at Google

 ---
 layout: page
 title: "Basic Display System in Apache Zeppelin"
 description: "There are several display systems available in Apache Zeppelin. By default, Zeppelin prints interpreter response as a plain text using %text display system. However, display systems for showing HTML, tables, markdown or even graph visualizations are also available."
 group: usage/display_system
 ---
 <!--
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 -->
 {% include JB/setup %}

 # Basic Display System in Apache Zeppelin

 <div id="toc"></div>

 ## Text

 By default, Apache Zeppelin prints interpreter response as a plain text using `text` display system.

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_text.png" />

 You can explicitly say you're using `text` display system.

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_text1.png" />

 ## Html

 With `%html` directive, Zeppelin treats your output as HTML

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_html.png" />

 ## Markdown

 You can render your output as markdown with the `%markdown` directive.

 ### Mathematical expressions
 HTML display system automatically formats mathematical expression using [MathJax](https://www.mathjax.org/). You can use
 `\\( INLINE EXPRESSION \\)` and `$$ EXPRESSION $$` to format. For example

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_formula.png" />


 ## Table

 If you have data that row separated by `\n` (newline) and column separated by `\t` (tab) with first row as header row, for example

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table.png" />

 You can simply use `%table` display system to leverage Zeppelin's built in visualization.

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table1.png" />

 If table contents start with `%html`, it is interpreted as an HTML.

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table_html.png" />

 > **Note :** Display system is backend independent.

 ## Network

 With the `%network` directive, Zeppelin treats your output as a graph. Zeppelin can leverage the Property Graph Model.

 ### What is the Labelled Property Graph Model?

 A [Property Graph](https://github.com/tinkerpop/gremlin/wiki/Defining-a-Property-Graph) is a graph that has these elements:

 * a set of vertices
     * each vertex has a unique identifier.
     * each vertex has a set of outgoing edges.
     * each vertex has a set of incoming edges.
     * each vertex has a collection of properties defined by a map from key to value
 * a set of edges
     * each edge has a unique identifier.
     * each edge has an outgoing tail vertex.
     * each edge has an incoming head vertex.
     * each edge has a label that denotes the type of relationship between its two vertices.
     * each edge has a collection of properties defined by a map from key to value.

 <img src="https://github.com/tinkerpop/gremlin/raw/master/doc/images/graph-example-1.jpg" />

 A [Labelled Property Graph](https://neo4j.com/developer/graph-database/#property-graph) is a Property Graph where the nodes can be tagged with **labels** representing their different roles in the graph model

 <img src="http://s3.amazonaws.com/dev.assets.neo4j.com/wp-content/uploads/property_graph_model.png" />

 ### What are the APIs?

 The new NETWORK visualization is based on json with the following params:

 * "nodes" (mandatory): list of nodes of the graph every node can have the following params:
     * "id" (mandatory): the id of the node (must be unique);
     * "label": the main Label of the node;
     * "labels": the list of the labels of the node;
     * "data": the data attached to the node;
 * "edges": list of the edges of the graph;
     * "id" (mandatory): the id of the edge (must be unique);
     * "source" (mandatory): the id of source node of the edge;
     * "target" (mandatory): the id of target node of the edge;
     * "label": the main type of the edge;
     * "data": the data attached to the edge;
 * "labels": a map (K, V) where K is the node label and V is the color of the node;
 * "directed": (true/false, default false) which tells if is directed graph or not;
 * "types": a *distinct* list of the edge types of the graph

 If you click on a node or edge on the bottom of the paragraph you find a list of entity properties

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_network.png" />

 This kind of graph can be easily *flatten* in order to support other visualization formats provided by Zeppelin.

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_network_flatten.png" />

 ### How to use it?

 An example of a simple graph

 ```scala
 %spark
 print(s"""
 %network {
     "nodes": [
         {"id": 1},
         {"id": 2},
         {"id": 3}
     ],
     "edges": [
 		{"source": 1, "target": 2, "id" : 1},
 		{"source": 2, "target": 3, "id" : 2},
 		{"source": 1, "target": 2, "id" : 3},
 		{"source": 1, "target": 2, "id" : 4},
 		{"source": 2, "target": 1, "id" : 5},
 		{"source": 2, "target": 1, "id" : 6}
 	]
 }
 """)
 ```

 that will look like:

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_simple_network.png" />

 A little more complex graph:

 ```scala
 %spark
 print(s"""
 %network {
     "nodes": [{"id": 1, "label": "User", "data": {"fullName":"Andrea Santurbano"}},{"id": 2, "label": "User", "data": {"fullName":"Lee Moon Soo"}},{"id": 3, "label": "Project", "data": {"name":"Zeppelin"}}],
     "edges": [{"source": 2, "target": 1, "id" : 1, "label": "HELPS"},{"source": 2, "target": 3, "id" : 2, "label": "CREATE"},{"source": 1, "target": 3, "id" : 3, "label": "CONTRIBUTE_TO", "data": {"oldPR": "https://github.com/apache/zeppelin/pull/1582"}}],
 	"labels": {"User": "#8BC34A", "Project": "#3071A9"},
 	"directed": true,
 	"types": ["HELPS", "CREATE", "CONTRIBUTE_TO"]
 }
 """)
 ```

 that will look like:

 <img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_complex_network.png" />
	---
	layout: page
	title: "Basic Display System in Apache Zeppelin"
	description: "There are several display systems available in Apache Zeppelin. By default, Zeppelin prints interpreter response as a plain text using %text display system. However, display systems for showing HTML, tables, markdown or even graph visualizations are also available."
	group: usage/display_system
	---
	<!--
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	{% include JB/setup %}

	# Basic Display System in Apache Zeppelin

	<div id="toc"></div>

	## Text

	By default, Apache Zeppelin prints interpreter response as a plain text using `text` display system.

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_text.png" />

	You can explicitly say you're using `text` display system.

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_text1.png" />

	## Html

	With `%html` directive, Zeppelin treats your output as HTML

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_html.png" />

	## Markdown

	You can render your output as markdown with the `%markdown` directive.

	### Mathematical expressions
	HTML display system automatically formats mathematical expression using [MathJax](https://www.mathjax.org/). You can use
	`\\( INLINE EXPRESSION \\)` and `$$ EXPRESSION $$` to format. For example

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_formula.png" />


	## Table

	If you have data that row separated by `\n` (newline) and column separated by `\t` (tab) with first row as header row, for example

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table.png" />

	You can simply use `%table` display system to leverage Zeppelin's built in visualization.

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table1.png" />

	If table contents start with `%html`, it is interpreted as an HTML.

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_table_html.png" />

	> Note : Display system is backend independent.

	## Network

	With the `%network` directive, Zeppelin treats your output as a graph. Zeppelin can leverage the Property Graph Model.

	### What is the Labelled Property Graph Model?

	A [Property Graph](https://github.com/tinkerpop/gremlin/wiki/Defining-a-Property-Graph) is a graph that has these elements:

	* a set of vertices
	* each vertex has a unique identifier.
	* each vertex has a set of outgoing edges.
	* each vertex has a set of incoming edges.
	* each vertex has a collection of properties defined by a map from key to value
	* a set of edges
	* each edge has a unique identifier.
	* each edge has an outgoing tail vertex.
	* each edge has an incoming head vertex.
	* each edge has a label that denotes the type of relationship between its two vertices.
	* each edge has a collection of properties defined by a map from key to value.

	<img src="https://github.com/tinkerpop/gremlin/raw/master/doc/images/graph-example-1.jpg" />

	A [Labelled Property Graph](https://neo4j.com/developer/graph-database/#property-graph) is a Property Graph where the nodes can be tagged with labels representing their different roles in the graph model

	<img src="http://s3.amazonaws.com/dev.assets.neo4j.com/wp-content/uploads/property_graph_model.png" />

	### What are the APIs?

	The new NETWORK visualization is based on json with the following params:

	* "nodes" (mandatory): list of nodes of the graph every node can have the following params:
	* "id" (mandatory): the id of the node (must be unique);
	* "label": the main Label of the node;
	* "labels": the list of the labels of the node;
	* "data": the data attached to the node;
	* "edges": list of the edges of the graph;
	* "id" (mandatory): the id of the edge (must be unique);
	* "source" (mandatory): the id of source node of the edge;
	* "target" (mandatory): the id of target node of the edge;
	* "label": the main type of the edge;
	* "data": the data attached to the edge;
	* "labels": a map (K, V) where K is the node label and V is the color of the node;
	* "directed": (true/false, default false) which tells if is directed graph or not;
	* "types": a distinct list of the edge types of the graph

	If you click on a node or edge on the bottom of the paragraph you find a list of entity properties

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_network.png" />

	This kind of graph can be easily flatten in order to support other visualization formats provided by Zeppelin.

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_network_flatten.png" />

	### How to use it?

	An example of a simple graph

	```scala
	%spark
	print(s"""
	%network {
	"nodes": [
	{"id": 1},
	{"id": 2},
	{"id": 3}
	],
	"edges": [
	{"source": 1, "target": 2, "id" : 1},
	{"source": 2, "target": 3, "id" : 2},
	{"source": 1, "target": 2, "id" : 3},
	{"source": 1, "target": 2, "id" : 4},
	{"source": 2, "target": 1, "id" : 5},
	{"source": 2, "target": 1, "id" : 6}
	]
	}
	""")
	```

	that will look like:

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_simple_network.png" />

	A little more complex graph:

	```scala
	%spark
	print(s"""
	%network {
	"nodes": [{"id": 1, "label": "User", "data": {"fullName":"Andrea Santurbano"}},{"id": 2, "label": "User", "data": {"fullName":"Lee Moon Soo"}},{"id": 3, "label": "Project", "data": {"name":"Zeppelin"}}],
	"edges": [{"source": 2, "target": 1, "id" : 1, "label": "HELPS"},{"source": 2, "target": 3, "id" : 2, "label": "CREATE"},{"source": 1, "target": 3, "id" : 3, "label": "CONTRIBUTE_TO", "data": {"oldPR": "https://github.com/apache/zeppelin/pull/1582"}}],
	"labels": {"User": "#8BC34A", "Project": "#3071A9"},
	"directed": true,
	"types": ["HELPS", "CREATE", "CONTRIBUTE_TO"]
	}
	""")
	```

	that will look like:

	<img src="{{BASE_PATH}}/assets/themes/zeppelin/img/screenshots/display_complex_network.png" />