How to import Base: ! when I get no method matching !??

Works fine for me.

```
julia> import Base: !
julia>
```

What are you doing and what is the exact error?

I get `ERROR: MethodError: no method matching !(::Vector.........`

so I want to know how wan I solve it with

Importing the function from `Base`

won’t help. It is already imported by default.

`!`

means logical negation. It is not defined for vectors. What is it supposed to return on a vector, e.g what should `![1,2,3]`

be?

`Base`

defines it for booleans, functions and missing values:

```
julia> methods(!)
# 3 methods for generic function "!":
[1] !(f::Function) in Base at operators.jl:1117
[2] !(x::Bool) in Base at bool.jl:35
[3] !(::Missing) in Base at missing.jl:101
```

You can use broadcasting `.`

to negate a vector of booleans for example

```
julia> .![true, false, true]
3-element BitVector:
0
1
0
```

When you get an error message, you must show all the code you ran to get that error.

Since the error message mentions `Vector`

, clearly you did something *after* `import Base: !`

that triggered the error. That is the important part to show.

This is a useful post to consult when asking questions: