How can I see function arguments in IPython Notebook Server 3?

In 1.0, the functionality was bound to ( and tab and shift-tab, in 2.0 tab was deprecated but still functional in some unambiguous cases completing or inspecting were competing in many cases. Recommendation was to always use shift-Tab. ( was also added as deprecated as confusing in Haskell-like syntax to also push people toward Shift-Tab as it works in more cases. in 3.0 the deprecated bindings have been remove in favor of the official, present for 18+ month now Shift-Tab.

So press Shift-Tab.

Try Shift-Tab-Tab a bigger documentation appears, than with Shift-Tab. It's the same but you can scroll down.

Shift-Tab-Tab-Tab and the tooltip will linger for 10 seconds while you type.

Shift-Tab-Tab-Tab-Tab and the docstring appears in the pager (small part at the bottom of the window) and stays there.

Adding screen shots(examples) and some more context for the answer of @Thomas G.

if its not working please make sure if you have executed code properly. In this case make sure import pandas as pd is ran properly before checking below shortcut.

Place the cursor in middle of parenthesis () before you use shortcut.

shift + tab

Display short document and few params

shift + tab + tab

Expands document with scroll bar

shift + tab + tab + tab

Provides document with a Tooltip: "will linger for 10secs while you type". which means it allows you write params and waits for 10secs.

shift + tab + tab + tab + tab

It opens a small window in bottom with option(top righ corner of small window) to open full documentation in new browser tab.