In python, I can use help(function, module, etc) to get documentation. Even if not documented, I can use dir(object) to discover things about it (e.g., find what’s in a module).
How do I do this with julia?
In python, I can use help(function, module, etc) to get documentation. Even if not documented, I can use dir(object) to discover things about it (e.g., find what’s in a module).
How do I do this with julia?
In the REPL, you can use ?function
to get interactive documentation.
This also works in the IJulia (Jupyter) notebook.
Both in the REPL and in a script:
@doc function-name
But, really, the best way to discover how to read the documentation is to read the documentation
As previously mentioned, in the REPL a line starting with ?
is a documentation lookup. E.g. ?map
will give you documentation about the function map
; this also works with types. Interestingly, this also works with packages; you can do ?PackageName
to see the readme for installed package PackageName
.
Sometimes you don’t know the function you need. Then you can use apropos
(not in help mode) to search. For example, maybe I don’t know how to create an identity matrix. apropos("identity")
will give a list of functions which may match.
Sometimes you have an object and don’t know what you can do with it. You can try methodswith(typeof(object))
(or just methodswith(T)
if T
is a type) to see available methods.
Since you also mentioned dir(object)
, you may also be interested in fieldnames(...)
which lists all fields of an object or type:
type MyType
x::Int
y::Int
end
fieldnames(MyType) # called on type ==> [:x, :y]
fieldnames(MyType(1, 2)) # called on instances ==> [:x, :y]
In case you want to look at actual implementation, you can use @edit
macro. For example:
@edit qr(rand(3,3))
will open qr.jl
in configured editor and point you to the corresponding lines (if editor support it).
I have had a blog post on this “in the works” for quite awhile. Right now it’s just a huge list of commands, and I want a little bit of a walk through it. Here’s a “public preview”
http://www.stochasticlifestyle.com/?p=96&preview=1&_ppp=8821b19e7b
If anyone wants to help me finish it, just let me know.
There’s also a nice overview by @astrieanna here: Julia Helps | juliabloggers.com
It’s not accessible
Huh, public preview links must reset after a few days.
http://www.stochasticlifestyle.com/?p=96&preview=1&_ppp=9f2c7dab73
Nice list! Seems to be missing “methods”.
thanks, preview link’s been expired again. This is a replicate of ChrisRackauckas’s original post.