Running a block of python code within vim

I’ve been configuring vim to work as a python IDE and have added quite a few enhancements. There’s a handy plugin called python-mode that really powers up your vim for python development. Some notable features include static code analysis, code completion, and executing the script with <Leader> m which prints the output in a new split.

But a lot of times what I really want to do is execute a few simple commands, or a simple for loop and checkout the results, and to do this I have to move out of vim to a separate window with a python interpreter. But that’s not required at all!

I found this really cool stack overflow answer that explains a very handy trick.

So lets say we want to execute the following two lines of python code and check it’s result.

print "Hello World"
print 3//2

Just follow these simple steps after typing the above two lines in your vim window:

1. Enter visual mode by pressing Esc and then v
2. Use j and k or the arrow keys to select the lines you want to execute.
3. Type :!python
4. Since you are in visual mode, you will see this displayed as :'<, '>!python
5. Press Enter

And that’s it! The result will be displayed in-place and will replace the selected block of code!

print "Hello World"
print 3//2

Will now be replaced by

Hello World
1

You can simply press u to undo this change and get back the lines of code you typed.

And that’s not it. You can run bash commands too.

1. Type ls -l
2. Enter visual mode and select the text
3. Type :!bash
4. Since you are in visual mode, you will see this displayed as :'<, '>!bash
5. Press Enter
6. Watch as the result is displayed in-place
7. Press u to undo this change

I think that’s a very handy feature! Hope that helps :)