Using Printf and @printf in blocks

New to Julia
1

A script like this:


using Printf
let
  @printf "%.2f" 3.14159
end

works fine.

However, if the “using Printf” is put inside the “let” block, an error occurs, as if Printf was not loaded:

let 
  using Printf
  @printf "%.2f" 3.14159
end

ERROR: LoadError: LoadError: UndefVarError: @printf not defined

2

The block is compiled before it is executed, and Printf needs to be loaded before the block can be compiled.

(Putting a using statement inside a let block will not restrict the scope of the exported functions anyway.)

3

Thank you. It confuses me a little bit, on the other hand, that this works:

let
   include("./file.jl")
end

file.jl:

using Printf
@printf "%.2f" 3.14159

I am glad it works, otherwise the includes would not be portable, but that means that
the include is not equivalent to the typing of the code in the same position.

4

No it isn’t and can’t be. It’s equivalent to eval.

1 Like
5

Excellent. Thank you.