How do I get auto-suggestions for array options when typing in Vim?

Let's say I type

a = [1, 2]

in a .py file in vim and when I type "a." and hit TAB, I would like to get suggestion me开发者_StackOverflow中文版nu that is related to lists.

Edit 1 in response to Robin's comment: I think it's possible in vim, because there is a plugin that checks if a given python code is a valid code (I don't know what the plugin is called). Take a look:

Recent versions of vim come with an omnicompletion script called pythoncomplete.

Open up a python file, and type

:set completefunc?

to check what the current completion function is. If you get back

completefunc=

then no completionfunction is currently set. You can set pythoncomplete to be the completion function by typing

:set completefunc=pythoncomplete#Complete

and you can set this to be the default for python files using (in your vimrc)

autocmd FileType python set completefunc=pythoncomplete#Complete

Now when you're in vim, you can use omnicomplete using Ctrl+X Ctrl+O and you should get a popup menu as shown below:

You can also bind this to the tab key in insert mode with (in your vimrc):

inoremap <Tab> <C-x><C-o>

To find out more about interacting with the dropdown menu that appears, try

:help ins-completion

Read one of the many blog posts on setting up Vim as a Python IDE. Here's one to get you started. In particular, you are interested in the OmniComplete function.

This is bound by default to the keystroke Ctrl-xCtrl-o but you can rebind it to the tab key.

Note that it is not sensitive to the type of a variable. It can complete for you if you type:

string.<ctl-x><ctl-o>

you'll get a list of the string object methods. But if you do as you described in your question something like:

x = "a string"

x.<ctl-x><ctl-o>

vim will not know that the variable x holds a string, and will not be able to supply a list of methods.

For information on omnicomplete:

:help omnifunc