Is it possible to do block-comments in Google Colab?

Question

In Jupyter Notebook, you can toggle/comment a block of selected code with Ctrl + /, but this doesn't work in Google Colaboratory notebooks. Is there a way to comment out several lines of Python code easily in a Colaboratory notebook?

I've looked in the documentation, but I came up short.

A related question is the subject of [a meta question](https://meta.stackoverflow.com/questions/417825/migrate-my-question-will-i-get-the-reputation-back). — Peter Mortensen, May 03 '22 at 09:27

score 39 · Accepted Answer · edited Jan 05 '20 at 10:34

39

In the default Colab keyboard shortcuts, you can block comment text using Ctrl+/.

If this does not work for you, check Tools->Keyboard Shortcuts and search for "Comment Current Line" to see what the shortcut is within your current settings.

edited Jan 05 '20 at 10:34

Misha Akopov

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answered Jan 02 '20 at 17:16

jakevdp

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So strange, I could swear I tried this out on Colab and it didn't work for me. Works now though. Thanks. – Levon Jan 02 '20 at 21:05
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If you're in Mac you need to push the Command key as well. – abcd Aug 04 '20 at 19:03
It is still not working for me. What do you mean by push the Command key? – Strickland Oct 24 '20 at 06:42
@abcd thanks! I can confirm the working shortcut on mac os is `Ctrl+Cmd+/` – Leonardo Nov 01 '20 at 17:12
Thanks @jakevdp! For me (in macOS Big Sur 11.4) it works to say **⌘ /** (that is, just cmd+/, no ctrl required). – Craig Reynolds Nov 24 '21 at 18:27

score 8 · Answer 2 · edited May 09 '22 at 19:21

8

You can select the lines of code and press (Ctrl + /) to comment or uncomment your selected lines of code.

You can also use triple single quotes (''') at the start and end of the code block you are interested to comment out.

''' ...Your commented code... '''

edited May 09 '22 at 19:21

Peter Mortensen

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answered Feb 25 '20 at 14:10

TanD

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I think your second solution is not correct. the three quotes it is for multiline string, not for comment. look this [notebook](https://colab.research.google.com/github/C4M-UofT/C4M-UofT.github.io/blob/master/notebooks/strings.ipynb#scrollTo=9Z2LNamTtG4W) – zana saedpanah Jun 07 '21 at 09:03

score 2 · Answer 3 · edited May 09 '22 at 20:29

2

If you are a Mac user, you can use Command + / for commenting out, and if you want to uncomment again, select the lines and then Command + /.

edited May 09 '22 at 20:29

Peter Mortensen

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answered Apr 06 '21 at 00:18

Mjachowdhury

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score 1 · Answer 4 · edited May 09 '22 at 20:30

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For Mac users who don't have an American keyboard like me: it seems like Colab thinks you are using an American keyboard for shortcuts, and so to make the '/' character you have to press the second button to the right of the 'm'. I'll leave an image to explain.

My keyboard looks like this:

My layout

As I said, I have to press the . key to make '/' as if I were using an American keyboard.

edited May 09 '22 at 20:30

Peter Mortensen

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answered May 06 '21 at 08:13

Liuker

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Are you sure it is not the ***next*** key, with "_"/"-" (underscore/dash)? [United States keyboard layout](https://en.wikipedia.org/wiki/British_and_American_keyboards#Windows_keyboards) – Peter Mortensen May 09 '22 at 20:34

score 0 · Answer 5 · edited May 09 '22 at 20:36

0

For Mac users:

first select the lines that you want to comment
second push these buttons: Command + Ctrl + Shift + /

Especially in the Italian keyboard it would be: Command + Ctrl + Shift + 7 (because the "/" character is combined with button "7")

edited May 09 '22 at 20:36

Peter Mortensen

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answered Jul 17 '21 at 15:15

Ali Tavana

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score 0 · Answer 6 · edited May 09 '22 at 20:40

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For some reason, I need to do Ctrl + Shift + :.

Which technically is Ctrl + /.

(I use an AZERTYUIOP keyboard.)

edited May 09 '22 at 20:40

Peter Mortensen

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answered Jul 30 '21 at 10:07

Tirbo06

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score 0 · Answer 7 · answered Feb 11 '23 at 06:28

0

if you come here with an Italian keyboard you should press: command + control + .

answered Feb 11 '23 at 06:28

code_lover

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MisterMiyagi · Answer 8 · 2022-05-03T10:33:58.490

When using Mac the keyboard shortcut is ⌘+/.

Note that depending on your layout, / cannot be directly addressed and its combination is different when combined with ⌘. For example, on a German keyboard / is [Shift]+7 but the combination ⌘+/ is ⌘+[Shift]+ß.

When you are unsure about which combination is correct, use the inbuilt keyboard viewer which provides a live view of the meaning of keys while selecting modifiers.

Keyboard Viewer: default keyboard mapping

Keyboard Viewer: modifier keys keyboard mapping

Is it possible to do block-comments in Google Colab?

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