Python's ternary operator

It's not so hidden!

Yes, like nearly every modern programming language Python also has a ternary operator, although it doesn't refer to it as such. While other languages typically use "?", Python chose to use "if".

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[teoconserv]

The "ter" comes from Latin, where "ter" means "three times" and "tres" just means "three", "ternus" is treefold and so on. So ternary ("ternarius") is three-ish, having the quality of three, being composed of partes tres (three parts). The root of "tri" lies in ancient Greek. So it's just a matter of which fancy dead language you find cooler to flex your smarts, when naming things.

[delta]

It's worth noting that there is merit to calling ?: in any form a "conditional expression." 'Ternary operators' are operators which accept 3 arguments, no matter what they do. For example, I could define a mathematical ternary operator [a $ b $ c ↦a * c - b]. The only reason programmers know what "the" ternary operator does is because afaik there is only one such operator (up to operator symbol and argument order) that is ever defined in any practical language, that being [a ? b : c].

[indigojones]

What's funny is that the python community held a vote for the ternary operator syntax. They came to a consensus on what syntax to use, then Guido came in and used his own.

[dixonstroi]

It didn't take me too long to learn to check date stamps on stack overflow for this very reason.

[juhotuho]

I literally had the same idea of flagging SO posts as outdated sometime ago, it would solve so many issues with outdated answers!

[vresod]

"Ternary (from Latin ternarius) or trinary is an adjective meaning 'composed of three items'." From Wikipedia

[sy-py]

It's called ternary because it comes from Latin.
"bīnus" is twofold, "ternus" is threefold, "quaternārius" is fourfold and so on

[gicknardner]

Stale info is turning into a huge annoyance on the internet. Now when searching stack overflow you often times have to pay attention to the dates just to make sure the answers aren't over a decade old! Sometimes that's fine, with python that's usually a huge problem.

[williamsusa]

How to learn Python? Many tutorials I don`t know where to get started

[-]

2:35 The one good place for these is golf code, where ``[a, b][cond]`` is the shortest way to evaluate conditionals in python. If you don't want b to be evaluated when not returned (maybe for recursion), you can use ``a * cond or b``. If a also can't be evaluated, you use ``cond and a or b``, which still saves 2 characters over the if-else syntax.

That said, golf code != good code, don't put this in your projects!

[Mutual_Information]

Lol sometimes the appropriate edit for a very old SO post.. is to delete it. I don't think people have the heart for that

[TMQuest]

Great video! An important discussion is when to use conditional expressions (ternary operators) in Python? There is a tradeoff between efficiency vs. readability. For short expressions, the conditional expression is certainly a great tool. But if the expressions are long, I prefer to write out the if-else on separate lines as this improves the readability. I also never use the conditional expressions in my own videos as not everyone is aware of them, to avoid alianating people.

[kalelsoffspring]

Seeing your facial expressions while discussing the oddities of Python is very satisfying hehe

[j]

“Ter” is the prefix used in *ordinal* numbers. Same as we say _third, _ not _threed._ So… one, two, three vs. primary, secondary, tertiary.

Somebody must have conceptualized the operation as ordinal (e.g., taking a third value) rather than cardinal (e.g., taking 3 values).

[guiorgy]

The third answer on StackOverflow mentiones that the answer is for Python versions before 2.5 so it's ok

[fazzitron]

Oh, I'd been using the wrong ones for a while now. Didn't know there was an official version now! 😅

[TimL_]

Valid criticism of stackoverflow at the end. I wish you'd explained exactly why those answers are wrong.

[POINTS]

Great examples of use cases where conditional expressions can be used. E.g. for setting a default immutable value.

[ilyam.]

Thank you for another great video! And please tune up your volume a bit, you sound way quieter than most youtubers.

[bakedbeings]

"Deprecated" might do the job of "Severely Out Of Date" without negative impact on reputation.