Data viewer

The data viewer in Sympathy for Data allows fast and easy inspection of the port data. It can be opened by double-clicking an output port of any executed node.

The appearance of the data viewer varies depending on the port data type.

Container types: list, tuple, dict, etc., have their own viewers that in turn include viewers for the data type they contain. For example, the viewer for a list of tables ([table]) will show a list viewer containing a table viewer.

It is also possible to launch the data viewer from the command line, to open saved .sydata-files, as described in the launch options.

List viewer

Shows a list of available items to the left and a viewer for the contained data type to the right. Selecting different items of the list will bring the data for the selected item into the right viewer.

Table viewer

The table viewer shows a data table to the left and can optionally show a plot to the right. The data toolbar is located above the data table.

Table viewer.

The table viewer showing a line plot.

The data toolbar of the table viewer has the following functions:

  • The search field allows a quick search of the column names. For further explanation of the functionality, see below.

  • The jump button, with some lines and an arrow, is for jumping to a specific row. When data is transposed it will jump (scroll the view) horizontally instead of vertically.

  • The document button toggles between a view of the table’s data and its attributes. In case there are no attributes, this view will be empty.

  • The transpose button flips the table so that rows become columns and columns become rows. This can be useful, for example, when there are many columns with long names, but fewer rows.

  • The graph button shows a menu with 3 different plot options: No plot (default), Line plot and Histogram plot. When Line or Histogram plot is selected a plot will be shown.

Data toolbar.

Data toolbar of the table viewer.

The data table also has a right-click context menu allowing quick selection of columns to plot as either x (Plot as x) or y (Plot as y) signal. Multiple columns can be plotted against the same x signal. Show histogram will show a histogram of the selected column.

The number of rows and columns (row x column) is shown in a little box on the bottom left of the data table.


Due to limitations of the underlying GUI framework, tables with more then 71’582’788 rows will be truncated in the table component of the data viewer. This will be shown with a line in red: Data truncated.


The plot can shown either a Line or a Histogram. These are different and have different options in the upper toolbar, etc., as seen in the different subsections below.


Plotting large amounts of rows and several columns can result in slow plotting and the GUI might become unresponsive.

The toolbar below the plot area allows for easy zooming, panning, and moving through the zoom/pan state history. It also has the option to save the current figure (Save icon) and alter the appearance of the lines or scatters of the plotted data (checkbox icon).

Line plot

Shows a scatter plot of the selected x and y columns.


Specifies the column used for the x axis.


Specifies the columns plotted as y-values. Multi-selection is allowed. Un/checking a column will remove or add it to the plot.

Line and marker button

Choose between Marker, Line and Line and marker for the plotted columns.

CSV button

Save the data to a CSV file, if cursors are used: save the data between the cursors, otherwise: save all data.

Cursor button

Show a menu with cursor options.

Plot preferences

Shows a menu with options for:

Auto downsampling

When checked, automatically determine the downsampling step from the data so that the number of data points plotted does not exceed the limit of 10000 points.


The downsampling step size (n) is used to limit the number of values plotted by taking the first and then every nth value.

  • 1: every value (no downsampling),

  • 2: every other value,

  • n: every nth value.

Upper plot toolbar.

Upper plot toolbar of the table viewer.


Specifies the column used to plot the histogram. Some statistics for the column’s data is shown in an inset in the histogram.

Plot preferences

Shows a menu with options for:

Auto downsampling

Same as for line plot, see above.


Same as for line plot, see above.

Auto bins

Automatically determine the number of bins from the data (0 - 10).

Number of bins

The number of bins used for the histogram.

Auto range

Automatically determine the histogram range (range min and range max) from the data.

Range min

Selecting the minimum value for the histogram range.

Range max

Selecting the maximum value for the histogram range.