Get a list of current variables in Julia Lang
JuliaJulia Problem Overview
I am new to Julia Lang. I am coming from the background of Matlab.
In Matlab, when pressing whos command I will get all variables in the current scope; and also, I can store them in another variable like x=whos; Is there such commands exists in Julia?
Example code in Matlab:
>> a=3;
>> b=4;
>> whos
Variables in the current scope:
Attr Name Size Bytes Class
==== ==== ==== ===== =====
a 1x1 8 double
b 1x1 8 double
prefix 1x16 16 char
Total is 18 elements using 32 bytes.
Julia Solutions
Solution 1 - Julia
An Update:
whos()
... is not working either in iJulia or at the command prompt in Julia-1.0.0.
It is working in Julia-0.6.4, though.
On the other hand,
varinfo()
....prints information about the exported global variables in a module. For Example,
julia-1.0> varinfo()
name size summary
–––––––––––––––– ––––––––––– –––––––––––––––––––––––––––––––
Base Module
Core Module
InteractiveUtils 154.271 KiB Module
Main Module
PyPlot 781.872 KiB Module
ans 50.323 KiB Plots.Plot{Plots.PyPlotBackend}
myrepl 0 bytes typeof(myrepl)
x 88 bytes 1×6 Array{Int64,2}
y 0 bytes typeof(y)
Hope, this is found useful.
Solution 2 - Julia
You can use Julia's whos functions just like that Matlab command.
julia> whos()
Base Module
Core Module
Main Module
ans Nothing
julia> x = 5
5
julia> whos()
Base Module
Core Module
Main Module
ans Int64
x Int64
Any modules (packages/libraries) you import into your local scope (using using) will also show up in the list (as Modules, like Base, Core, and Main above).
Additionally, you can ask about names exported by Modules. Base is the module containing the standard library.
julia> whos(Base)
! Function
!= Function
!== Function
$ Function
% Function
& Function
* Function
+ Function
.... (lots and lots more)
Considering that that result scrolls way off my screen, you can understand why you'd want to filter the results. For that you can use Regexes. (For more info on Julia's regexes, see this manual section)
julia> whos(r"M")
Main Module
julia> whos(Base, r"Match"i)
DimensionMismatch DataType
RegexMatch DataType
each_match Function
eachmatch Function
ismatch Function
match Function
matchall Function
I wasn't aware of the whos function before you asked, so thanks for helping me learn something new too. :)
Julia issue #3393 on github is about adding memory sizes to the whos output. It also references making whos return a value rather than just printing the information out.
Solution 3 - Julia
Not sure if there is something better, but
names(Main)[4:end]
seems to work. The [4:end] part is because it includes :Main, :Core and :Base which I think you would not want. I hope they will always be at the beginning.
Solution 4 - Julia
whos() is not available in newer versions of Julia (1.0 onward). Use varinfo() instead. For example, varinfo(Core,r".*field.*")
Solution 5 - Julia
As of version 1.1 there is also the @locals macro
> The experimental macro Base.@locals returns a dictionary of current local variable names and values