IntelliSense

Visual Studio IntelliSense displays information about functions you can call, members of objects, function arguments, and code snippets directly in your line of sight as you write code. It also displays possible completions as you type, and completes when you press the Tab or Enter keys (see editor options for the Advanced tab). IntelliSense is available in both the editor and the interactive window.

IntelliSense showing a function signature

When typing a function or other statement, IntelliSense provides an auto-completion menu filtered (case-sensitively) by what you've already entered:

IntelliSense auto-completion menu

Pressing Tab (or Enter, or Space, depending on how options are set), inserts the item selected in the dropdown. You can change the selection with the arrow keys.

IntelliSense also provides suggestions for members of R objects:

IntelliSense suggestions for object members

Pressing ESC dismisses the menu altogether. You can bring it back up with Ctrl+Space.

Typing the opening ( for a function call inserts the closing ) and brings up signature help as shown earlier:

IntelliSense signature help for a function

Again, ESC dismisses the popup; for function signatures, you can bring it up again with Ctrl+Shift+Space.

Tip

If you find the parameter help is obscuring text underneath it, as can be the case in the file editor, you can press and hold the Ctrl key to make the parameter help text translucent.

IntelliSense for user-defined functions and variables

IntelliSense applies for user-defined functions in the same file, including name-parameter completion:

IntelliSense for user-defined functions

IntelliSense parameter completion for user-defined functions

IntelliSense also applies for variables in the same file and the current session:

IntelliSense variable completion

Note

In the interactive window, IntelliSense considers only names in the current R session and ignores files in your project.

Code suggestions

When a light bulb (called smart tag) appears in the margin, Visual Studio is suggesting that there is a shortcut available for a commonly used action. For example, hover over a line that contains a library statement in the editor and you'll see a light bulb. Selecting the light bulb displays available options:

Smart tags for R in the editor