It depends on the type of heating, how it is controlled, and how you pay for your electricity.
If you pay full price for your electricity - then electric heating is by far the most expensive way of heating (in terms of fuel costs).
However, if you get the electricity for heating at a discount, then it can be only slightly more expensive than gas or other fuels. However, a lot depends on the heating controls, etc.
It's taken me quite a while to work out how my electric heating works - however, now that I know how it works it I can program it to be reasonable economical. The people who lived here before me clearly hadn't worked it out - because when I moved in the full-price meter reading was enormous, and the discount meter reading was far lower than I would have expected.
If you only heat rooms that are occupied, only when they are occupied, then this can work out quite cheap - this is easy with electric, but much harder with gas.