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Comment by StavrosK | Hacker News Reader

I will agree with everything but the first one. I prefer functions that claim to return True or False to return precisely that, rather than Truthy/Falsy values. Otherwise, if I want to do "if func() is other_val" where "other_val" is True or False, it will fail.

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Yes, you should never do ‛foo is True either :).

Also, here the point is that <some stuff> was a boolean expression already.

Well, how else would you check if a return value matches a True/False variable? if <var> and <retval>? That's horrible!

Obviously its a matter of personal preference but PEP 8 (official Python style guide) disagrees with you.

PEP 8 only mentions truth checks, it doesn't mention if functions' return values should be True or the truthy value. Personally, I find it very unclean to have your function return half a string, or some unrelated int or something similar when your function is called, e.g. "is_member()".

Ah, sorry think we are talking about different things. I thought you where complaining about:

  if [something]:

  if [something] is True:

In the case I think you are talking about I would probably agree with you that returning some non-boolean is less clean, though I would probably just use the equality operator to force a boolean result:

  def foo(i):
    return i == 0

Yep, we agree exactly. I just don't like "return i", and would rather do "return i is True" or something.

In that case, you can always opt to return bool(return_value), which lets you return True or False without the ugly if / else : )

Indeed, or just "return var == True".

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