Using a key modifier with blender modal

Question

does anyone know how to make a modal do something different if i have a key held? This is what i have at the moment:

        if event.type == 'MOUSEMOVE': 
            if event.type == 'LEFT_SHIFT' and event.value == 'PRESS':
                self.value = (event.mouse_region_x - self.mouse_x_initial)
                print(self.value)

            self.value = event.mouse_region_x - self.mouse_x_initial

Answer 1

The event parameter has boolean properties for ctrl, alt, shift and oskey. Test these to know if one of the keys is being held at the time of the event.

def modal(self, context, event):
    if event.type == 'MOUSEMOVE':
        if event.ctrl:
            print('Ctrl is down')
        if event.shift:
            print('shift is down')
        if event.alt:
            print('alt is down')
    elif event.type == 'ESC':
        return {'CANCELLED'}
    return {'RUNNING_MODAL'}

As the boolean properties don't distinguish between left and right keys, you would need to keep a record of the previous event and also check that to know which action to take if you wanted them to work differently.