cycle-workspace.py

#!/usr/bin/env python

# cycle-workspace
#   Moves the currently active workspace to the next active display
#   Depends on i3-py (`pip install i3-py`)
 
import i3

# figure out what is on, and what is currently on your screen.
focused_workspace = list(filter(lambda s: s['focused'], i3.get_workspaces()))[0]
outputs = list(filter(lambda s: s['active'], i3.get_outputs()))

# find the index of the currently focused workspace
currentIndex = 0
for i, output in enumerate(outputs):
    if output['name'] == focused_workspace['output']:
        currentIndex = i
        break
    
# find the next workspace
nextIndex = currentIndex + 1
if nextIndex >= len(outputs):
    nextIndex = 0
other_workspace = outputs[nextIndex]

# send current to the no-active one
i3.command('move', 'workspace to output '+other_workspace['name'])

Version of this for sway: https://gist.github.com/ineentho/60008b6f9603e533c612c1999fa46406