6.1

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Working with Python

This is a quick summary of how to use python scripts in Workbench. To learn more about this, see the further tutorials on the home page. Even if you are a novice at Python, it is useful to know how to run a script as you can produce one within Mantid: from the “Generate a script” button on a plot toolbar, or from project recovery when you reopen Mantid after a crash.

Within the Mantid you can make use of the script window or IPython prompt to manipulate data and build plots exactly to your specifications in ways that you would not be able to with the interface alone.

A view of the Workbench script window

You can also use the IPython tab below the script editor to change to an inline Python interpreter. Both the python interpreter and scripts run through Mantid are able to interact with Mantid workspaces, plot and algorithms.

1. Default imports

By default any new script opened in Workbench will come with some default imports:

from mantid.simpleapi import *

This imports all the algorithms from Mantid to be used within your Python script.

import matplotlib.pyplot as plt
import numpy as np

This imports Matplotlib for use as well as the excellent NumPy package.

These imports used to happen automagically for you invisibly in Mantidplot. But in the workbench they are visibly added at the top of the script, so script that work in the workbench will work elsewhere as well.

2. Tabs and multiple scripts

To open a new script you can click on the + button, or to open an existing script in a new tab go to “File” -> “Open Script” in the Workbench taskbar or use the hotkey Ctrl + o. From the script window you can also tab different scripts working on each independently and multiple scripts can be run simultaneously. Workbench will restore any tabs that were open the last time Mantid was shut down.

3. Running, aborting, and options

From here you can run or abort your script, toggle options for accessibility, and use the find and replace tool.

A view of the Workbench script options.
  • Run: This executes the currently selected text in your script, if nothing is selected it will run the entire script. The green play button serves as a shortcut for this option.
  • Run All: This will run the entire script regardless of whether any text is selected.
  • Abort: This immediately aborts the currently running script. The red stop button serves as a shortcut for this option.
  • Find/Replace: this opens the find and replace toolbar which can be used to make quick mass changes to your script or find sections of code.
  • Comment/Uncomment: This tool comments out or removes commenting on highlighted lines by adding or removing # at the beginning of the line.
  • Toggle Whitespace visible: Turning this on will make all spaces appear as faint dots and all tabs appear as arrows.
  • Tabs to spaces/Spaces to tabs: This will convert any tabs highlighted into groups of 4 white spaces or vice versa.

The toggle whitespace visible option is global and will affect the appearance of all your tabs.

4. Status

The status bar tells you if the code in the currently open tab is running or not. If the code has been run previously the status bar will give details of the previous run including runtime, and whether the code ran without errors.