"if" condition for boolean settings: == 1, == True or just omit?

Question

Here is simple ST plugin. Is there a difference between commented lines? Personally, I don't see any difference in how they work, just a difference in visual appearance.

However, some plugin developers prefer second version (== 1), which looks just useless and ugly for me. Probably there are some reasons to prefer it?

import sublime_plugin

class ExpandUnexpandTabsCommand(sublime_plugin.EventListener):
    def on_pre_save(self, view):

        # if view.settings().get("translate_tabs_to_spaces"):
        # if view.settings().get("translate_tabs_to_spaces") == 1:
        # if view.settings().get("translate_tabs_to_spaces") == True:
            view.run_command("expand_tabs")
        else:
            view.run_command("unexpand_tabs")

Answer 1

It depends on what the possible values are.

• If the file must have 0 or 1 in it, anything else is an error, and you're reading it as an int, then you probably want == 1.
• If the file can have either True or no entry at all, and you're using get(…) instead of [] so you get back None whenever it's not True, then you want to just test the truthiness. (Or maybe is not None, but definitely not == True or == 1.)

The rule is pretty simple: when writing a test, write what you mean to test.

Different tests mean different things:

• if spam:: passes if spam is anything truthy. That means anything besides None, False, numeric zero, or empty containers.

• if spam == 1:: passes if spam is the number 1.

• if spam is True:: passes only if spam is the special constant True. If you want to make sure other truthy values fail, and only True counts, use is. You rarely want this.

• if spam == True:: passes if spam is the special constant True, or some object equal to it. If you've gone out of your way to write a class whose __eq__ tests for True or something, then you might want this test, but it's hard to imagine why you would otherwise.

It happens to be true that 1 == True. But writing == True when you want to test for the number 1, or == 1 when you want to test for True but not other truthy values, is misleading to anyone who understands idiomatic Python, and mildly confusing to anyone who doesn't, and there's no benefit to anyone. So don't do it.

And writing either of those when you want to test for anything truthy isn't just misleading, it's wrong.