# Creating Networks There are 4 different ways of creating networks in Cytoscape: 1. Importing pre-existing, fixed-format network files. 2. Importing pre-existing, unformatted text or Excel files. 3. Importing data from from public databases. 4. Creating an empty network and manually adding nodes and edges. ## Import Fixed-Format Network Files Network files can be specified in any of the formats described in the **[Supported Network Formats](Supported_Network_File_Formats.md#supported-network-file-formats)** section. Networks are imported into Cytoscape via **File → Import**. The network file can either be located directly on the local computer, or found on a remote computer (in which case it will be referenced with a URL). ### Load Networks from Local Computer In order to load a network from a local file you can select **File → Import → Network from File...** or click on  on the tool bar. Choose the correct file in the file chooser dialog and press **Open**. Some sample network files of different types have been included in the sampleData folder in Cytoscape. After you choose a network file, another dialog will pop up. Here, you can choose either to create a new network collection for the new network, or load the new network into an existing network collection. When you choose the latter, make sure to choose the right mapping column to map the new network to the existing network collection.  Network collections in Cytoscape are used to organize related networks, for example subnetworks. Networks in a collection are linked through the **shared name** node attribute; the **shared name** attribute will be added upon import. This attribute is useful when you want to change a node name across all networks in a collection. Alternatively, you can simply drag and drop a network file from the desktop into the **Network** tab of the **Control Panel**, rather than selecting the file from the menu option. Network files in SIF, GML, and XGMML formats may also be loaded directly from the command line using the _-N_ option. ### Load Networks from a Remote Computer (URL import) To load a network from a remote file, select **File → Import → Network from URL...**. In the import network dialog, insert the appropriate URL, either manually or using URL bookmarks. Bookmarked URLs can be accessed by clicking on the arrow to the right of the text field (see the Bookmark Manager in [Preferences](Cytoscape_Preferences.md#cytoscape-preferences) for more details on bookmarks). Also, you can drag and drop links from a web browser to the URL text box. Once a URL has been specified, click on the OK button to load the network.  For network files stored in cloud storage, the default URL does not always work in Cytoscape and requires transformation before it can be used. Here are examples of transformation of the default URL for some common cloud storage options: #### Dropbox #### * Default URL: https://www.dropbox.com/s/077w3i4500dxrsm/galFiltered.sif?dl=0 * Cytoscape URL: https://dl.dropboxusercontent.com/s/077w3i4500dxrsm/galFiltered.sif **Instructions**: Replace `www.dropbox.com` with `dl.dropboxusercontent.com` AND remove `?dl=0` #### Google Drive #### For files smaller than 100K: * Default: https://drive.google.com/file/d/1hHO4ErMx7HMo-_sRV_PfeoM3lnn6ZDLw/view?usp=sharing * Cytoscape URL: https://drive.google.com/uc?export=download&id=1hHO4ErMx7HMo-_sRV_PfeoM3lnn6ZDLw **Instructions**: Replace `file/d/` with `uc?export=download&id=` AND remove `/view?usp=sharing` You may see an intermediate import window, described in the section below, where you may need to change the delimiter and define source, target and interaction. For this particular example, in **Advanced** change the **Delimiter** to **Space**, unselect **Use first line as column names** and set the first column as **Source**, the third column as **Target** and the second column as **Interaction Type**. #### GitHub #### * Default URL: https://github.com/bdemchak/cytoscape-jupyter/blob/main/sanity-test/data/galFiltered.sif * Cytoscape URL: https://raw.githubusercontent.com/bdemchak/cytoscape-jupyter/main/sanity-test/data/galFiltered.sif **Instructions**: Replace `github.com` with `raw.githubusercontent.com` AND remove `/blob` Another issue for network import is the presence of firewalls, which can affect which files are accessible to a computer. To work around this problem, Cytoscape supports the use of proxy servers. To configure a proxy server, go to **Edit → Preferences → Proxy Settings...**. This is further described in the **[Preferences](Cytoscape_Preferences.md#cytoscape-preferences)** section. ## Import Networks from Unformatted Table Files Cytoscape supports the import of networks from delimited text files and Excel workbooks using **File → Import → Network from File...**. An interactive GUI allows users to specify parsing options for specified files. The screen provides a preview that shows how the file will be parsed given the current configuration. As the configuration changes, the preview updates automatically. In addition to specifying how the file will be parsed, the user must also choose the columns that represent the source and target nodes as well as an optional edge interaction type. For detailed instructions, see Basic Operations below.  ### Supported File Types The import function supports delimited text files and Microsoft Excel Workbooks. For Excel Workbooks with multiple sheets, one sheet can be selected for import at a time. The following is a sample table file:

Sample Network in Table

source	target	interaction	boolean data	string data	floating point data
YJR022W	YNR053C	pp	TRUE	abcd12371	1.2344543
YER116C	YDL013W	pp	TRUE	abcd12372	1.2344543
YNL307C	YAL038W	pp	FALSE	abcd12373	1.2344543
YNL216W	YCR012W	pd	TRUE	abcd12374	1.2344543
YNL216W	YGR254W	pd	TRUE	abcd12375	1.2344543

The network table files should contain at least two columns for creating network with edges. If the file has only one column, the created network will not contain any edges. The interaction type is optional in this format. Therefore, a minimal network table looks like the following:

Minimal Network Table

source	target
YJR022W	YNR053C
YER116C	YDL013W
YNL307C	YAL038W
YNL216W	YCR012W
YNL216W	YGR254W

One row in a network table file represents an edge and its edge data columns. This means that a network file is considered a combination of network data and edge column data. A table may contain columns that aren't meant to be edge data. In this case, you can choose not to import those columns by clicking on the column header in the preview window. This function is useful when importing a data table like the following (1):  This data file is a tab-delimited text file and contains network data (interactions), edge data, and node data. To import network and edge data from this table, choose _Unique ID A_ as source, _Unique ID B_ as target, and _Interactor types_ as interaction type. Next, turn off columns used for node data (_Alt ID A_, _species B_, etc.). Other columns can be imported as edge data. The network import function cannot import node table columns - only edge table columns. To import node table columns from this table, please see the **[Node and Edge Column Data](Node_and_Edge_Column_Data.md#node-and-edge-column-data)** section of this manual. Note (1): This data was adapted from the *A merged human interactome* datasets by Andrew Garrow, Yeyejide Adeleye and Guy Warner (Unilever, Safety and Environmental Assurance Center, 12 October 2006). ### Basic Operations To import network from text/Excel tables, please follow these steps: 1. Select **File → Import → Network from File...** or click on  on the tool bar. 2. Select a table file in the file chooser dialog. 3. Define the interaction parameters by specifying which columns of data contain the **Source Interaction**, **Target Interaction**, and **Interaction Type**. Clicking on on the arrow to the right of any column header will bring up the interface for selecting source, interaction and target:  4. (Optional) Define edge table columns, if applicable. Network table files can have edge table columns in addition to network data. - Enable/Disable Table Columns: You can enable/disable column data by selecting the  symbol in the column editor.  - Change Column Name and Data Types: You can also modify the column name and data type in the column editor. For more detail, see **Modify Column Name/Type** below. 5. Click the **OK** button. #### Import List of Nodes Without Edges The table import feature supports lists of nodes without edges. If you select only a source column, it creates a network without interactions. This feature is useful with the node expansion function available from some web service clients. Please read the section **[Importing Networks from External Database](Creating_Networks.md#import_networks_from_public_databases)** for more detail. ### Advanced Options  You can select several options by clicking the **Advanced Options** button in the main import interface. - **Delimiter**: You can select multiple delimiters for text tables. By default, _Tab_ and _Space_ are selected as delimiters. - **Default Interaction** - **Transfer first line as column names**: Selecting this option will cause all edge columns to be named according to the first data entry in that column. - **Start Import Row**: Set which row of the table to begin importing data from. For example, if you want to skip the first 3 rows in the file, set 4 for this option. - **Ignore lines starting with**: Rows starting with this character will not be imported. This option can be used to skip comment lines in text files. ### Modify Column Name/Type In the **Import Network from Table** interface, you can change the name and data type of column by clicking on any column header:  Column names and data types can be modified here. - **Modify Column Name** - type in a new column name. - **Modify Column Data Type** - The following column data types are supported: - String - Boolean (True/False) - Integer - Floating Point - List of (one of) String/Boolean/Integer/Floating Point Cytoscape has a basic data type detection function that automatically suggests the column data type according to its entries. This can be overridden by selecting the appropriate data type from the radio buttons provided. For lists, a global delimiter must be specified (i.e., all cells in the table must use the same delimiter). ## Import Networks from Public Databases Cytoscape allows you to import networks from public databases. Users can access various kinds of databases through this function, under **File → Import → Network from Public Databases...**. A **Search bar** is also available at the top of the **Network** panel in the **Control Panel**. From the search bar, you can direclty access several public databases.  ### What is a Web Service? A web service is a standardized, platform-independent mechanism for computers to interact over the internet. These days, many major biological databases publish their data with a web service API: - List of Biological Web Services: [https://incubator.apache.org/projects/taverna.html](https://incubator.apache.org/projects/taverna.html) - Web Services at the EBI: [https://www.ebi.ac.uk/Tools/common/tools/help/](https://www.ebi.ac.uk/Tools/common/tools/help/) Cytoscape core developer team have developed several web service clients using this framework. Cytoscape supports many web services including: - [PSICQUIC](https://psicquic.github.io/): Standard web service for biological interaction data sets. The full list of PSICQUIC-compatible databases is available [here](http://www.ebi.ac.uk/Tools/webservices/psicquic/registry/registry?action=STATUS). PSICQUIC is available from the **Search bar**. - [Pathway Commons](http://www.pathwaycommons.org/): Integrated data from pathway and network resources. The full list of supposrted resources is available [here](http://www.pathwaycommons.org/pc2/datasources). Pathway Commons is available from **File → Import → Network → Public Databases...**. - [STITCH](http://stitch.embl.de/) and [STRING](https://string-db.org/): STITCH is a database of known and predicted interactions between chemicals and proteins. STRING is a database of known and predicted protein-protein interactions. STITCH and STRING are available from the **Search bar** and from **File → Import → Network → Public Databases...**. - [NDEx](http://www.ndexbio.org/): The Network Data Exchange (NDEx) Project provides an open-source framework where scientists and organizations can share, store, manipulate, and publish biological network knowledge. NDEx is available from the **Search bar**, from **File → Import → Network from NDEx...** and in the **Toolbar** via the **NDEx Button**. ### Example: Retrieving Networks from NDEx - In the **Search bar**, select NDEx from the drop-down menu and type in one or more search terms, such as BRCA1. - Click **Enter** to start the search. - The CyNDEx-2 **Find Networks** dialog window will open and show the search results - By default, results are returned in order of relevance based on the search terms you provided; you can change the sorting criteria by clicking on the column headers. - Mark the **My Networks** checkbox at the top of the results table to only display the results that you own (you must have an NDEx account and a profile associated to the CyNDEx Browser... see the section [Export options](Export_Your_Data.md#export_ndex) for more details). - Click the **Black Arrow Icon** on the left hand side of a network to import it into Cytoscape and visualize it. When you have finished loading networks, dismiss the dialog window by clicking the **Close Dialog** button.  You can also find a network via its UUID by using the *uuid:* selector in your search (e.g., **uuid:50e3dff7-133e-11e6-a039-06603eb7f303**) CyNDEx-2, like NDEx, uses standard [Lucene Syntax](https://lucene.apache.org/core/2_9_4/queryparsersyntax.html) as its network search language. For additional information, see [Searching Networks in NDEx](http://home.ndexbio.org/finding-and-querying-networks/). More information about CyNDEx-2, see the [CyNDEx-2 App Store](http://apps.cytoscape.org/apps/cyndex2) page. Finally, It is also possible to access the NDEx Import and Export dialogs via the NDEx button in the main **Cytoscape Toolbar**, which will display the two otions on click.  ## Create a New Network or Edit One Manually A new, empty network can also be created and nodes and edges manually added. To create an empty network, go to **File → New Network → Empty**, and then manually add network components by right clicking on the network canvas or on a node. You can edit an existing network using the same process. ### Adding a Node To add a new node, right-click on an empty space of the network view panel. Select **Add → Node** item from the pop-up menu.  ### Adding an Edge To add an edge to connect nodes, right-click on the source node. Select **Edit → Add Edge** from the pop-up menu. Next, click on the target node. The Images below show the two steps for drawing an edge between two nodes. You can abort the drawing of the edge by pressing Esc key. You can also select two or more nodes to connect and in the right-click menu select **Add → Edges Connecting Selected Nodes** to create edges connecting all selected nodes.   You can delete nodes and edges by selecting a number of nodes and edges, then selecting **Edit → Cut**. You can also delete selected nodes and edges from the **Edit** menu, under **Edit → Delete Selected Nodes and Edges...**. You can recover any nodes and edges deleted from a network by going to **Edit → Undo**. ### Grouping Nodes Any number of nodes can be grouped together and displayed as either one group node or as the individual nodes. To create a group, select two or more nodes and right-click to select **Group → Group Selected Nodes**. You will be prompted to select a name for the group node. Once a group is created, you can use the right-click menu to collapse or expand the group. You can also quickly collapse/expand a group by double-clicking on the group node or any of its children to toggle back and forth. **Collapsed group**  **Expanded group**  The appearance and behavior of grouped nodes depends on the [group settings](Cytoscape_Preferences.md#managing_group_view) in effect when the group is created. Settings can be managed for the entire Cytoscape session (via **Edit → Preferences → Group Preferences...**) or for a specific group (right-click **Preferences → Group Preferences...**). ### Adding Network Annotations [Annotations](Annotations.md) in the form of text, images or shapes can be added to the network canvas by right-clicking anywhere on the canvas and selecting one of the **Annotation** choices in the **Add** menu. You can add an image of your own, choose from a shapes library or add either plain or bounded text. Shapes and text are customizable and any added annotations can be edited from the right-click context menu.