Determine version of a specific package

Question

How can I get the version number for a specific package?

The obvious way is to get the dictionary with all installed packages, and then filter for the one of interest:

pkgs = Pkg.installed(); pkgs["Datetime"] 

Getting the list of all installed packages is very slow though, especially if there are many packages.

Answer 1

EDIT: For Julia version 1.1+

Use the Pkg REPL notation:

] status                        # Show every installed package version ] status pkgName                # Show the specific version of the package ] status pkgName1 pkgName2      # Show the named packages. You can continue the list. 

The ] enters the Pkg REPL, so you basically write status ...

So in your case, write after entering the Pkg REPL:

status DataFrame 

Or use the object-oriented approach (NB: Here you don't enter the Pkg REPL, i.e. DON'T use ]:

Pkg.status("DataFrame") 

EDIT: For Julia version 1.0

Pkg.installed seems to have "regressed" with the new package system. There are no arguments for Pkg.installed. So, the OP's original method seems to be about the best you can do at the moment.

pkgs = Pkg.installed(); pkgs["Datetime"] 

EDIT: For Julia version upto 0.6.4

You can pass a string to Pkg.installed. For example:

pkgs = Pkg.installed("JuMP") 

I often check available calling arguments with methods. For example:

julia> methods(Pkg.installed) # 2 methods for generic function "installed": installed() at pkg/pkg.jl:122 installed(pkg::AbstractString) at pkg/pkg.jl:129 

or

julia> Pkg.installed |> methods # 2 methods for generic function "installed": installed() at pkg/pkg.jl:122 installed(pkg::AbstractString) at pkg/pkg.jl:129