# How to qualify operators like *, + , etc

This should be an easy one, I am trying to run this code

``````import Measurements as M
import MonteCarloMeasurements as MCM
using Measurements
using MonteCarloMeasurements

n = 100
x = rand(n,5)
e = rand(n,5)/100

using BenchmarkTools, Statistics
@benchmark cov(x) .- cov(x .M.± e)
@benchmark cov(x) .- cov(x .MCM.± e)
``````

and I have this error

`ERROR: syntax: space before "." not allowed in "x ."`

I have tried a few combinations like .M(.±) with no luck. How should we qualify something like `x .± e`?

`M.:±` should work. You can’t use that as an infix operator though, so you will have to call it as `M.:±.(x, e)`.

3 Likes

Great! Thanks @simeonschaub !