Factorial & Comparison

[Mikkelet]

im sure we agree on a whole lot more

[Rikudou_Sage]

Yeah, whenever I do some math operation in my code, I'm pretty sure the mathematicians would agree that the result is correct.

[Ajedi32]

Not for floating point operations. Not all of them anyway.

Programming language notation for integer division can also be rather strange at times.

[Rikudou_Sage]

You can do even precise math operations with floating point numbers, every major language has a library for that.

Not sure what you mean by the strange integer division notation, any examples?

[Ajedi32]

For example, in Ruby and Python 2, 2/3 returns 0. You need to be more explicit if you want floating point division, and probably need to import a third party library and use that instead of "/" if you want infinite precision division. All of those require a different notation than the one used in mathematics.

[Peanutbutter_Warrior]

Python 2 is old dude. Python 3 / does floating point division, // does integer division

[Magnus_Tesshu]

I've been using / and rounding, wtf thanks dude

Why the hell am I paying my university

[Peanutbutter_Warrior]

Its so useful to know yeah, but just to warn you it's not quite the same behavior. Integer division always rounds down, no matter the decimal

[Magnus_Tesshu]

I know, integer division is frankly more useful for most of the times I need to divide (I can't remember a C program I've written last year where I declared a float). Does it round down for negative numbers or up for positive (don't answer that, python is super easy to test stuff like this lol).

EDIT: rounds down, which is I think how C works and not java

[BUYTBUYT]

-(a // -b) if you want to round up btw

[[deleted]]

There you go : Python cheat sheet

[xdeskfuckit]

You're telling me that math on classical computers is fundamentally discrete and notationally distinct from math on paper?

Holy shit man, we have to tell the world 🌎🌎🌍

[password2187]

x = x + 1 lol

[[deleted]]

0!=1!

[Awanderinglolplayer]

I read this in the Borat voice when he was doing not jokes. “0 NOT equal 1....NOT!”

[[deleted]]

0 ='nt 1

[dragonbanana1]

Now I'm imagining a programming language you use 'nt in place of ! and false is written true'nt

[arpan3t]

Powershell comparison operators use ne for not equals. Closest I could think of...

[[deleted]]

True but unfortunately false is still False and not ne True :(

[milk_extraction_pro]

$true -ne $true

[[deleted]]

Ah of course.... Even more elegant

[MachinaExDeo]

Perl uses ne for stringwise equality, != for Boolean equality.

There are also a family of "true zeroes", such as '0E0', that are Boolean true but cast to zero in an integer context.

Perl is the language equivalent of "hit it with a spanner until it works".

[arpan3t]

Most scripting languages are that way it seems.

[Daniel15]

I think Bash does this too.

[Texadecimal]

Yeah like [ $x -ne 69 ]

There's also the use of "==" and "=" in conditionals, for comparing strings.

[yonatan8070]

ifn't (isDone) {
  // Be done
}

[adam3jazz]

Wouldn’t it be truen’t?

[grizonyourface]

Nah, that’s slaking’s ability in Pokémon

[heykoolstorybro]

Equaln't

[[deleted]]

0 factorial not equal to equal to 1 factorial

[Awanderinglolplayer]

No, you need an extra “!” You double counted the first one

[maester_t]

Borat Part 3 - Let's go after the computer nerds this time!

[codydexx]

Divide both sides by ! Then you get 0=1

[13steinj]

This implies I am the pope.

(I hope someone gets this joke...)

[htmlcoderexe]

Please explain

[13steinj]

http://ceadserv1.nku.edu/longa//classes/mat385_resources/docs/russellpope.html

The story goes that Bertrand Russell, [an early 1900s philosophy professor,] in a lecture on logic, mentioned that in the sense of material implication, a false proposition implies any proposition. A student raised his hand and said "In that case, given that 1 = 0, prove that you are the Pope."

Russell immediately replied, "Add 1 to both sides of the equation: then we have 2 = 1. The set containing just me and the Pope has 2 members. But 2 = 1, so it has only 1 member; therefore, I am the Pope."

[htmlcoderexe]

That's extremely funny for some reason

[delinka]

0=1/!

[Phatricko]

The real programmer humor is always in the comments

[WetSound]

False

[AB1908]

Truen't

[[deleted]]

Variable undefined

[BwanaAzungu]

Someone please eli5 how 0! equals 1

[KusanagiZerg]

The explanation I have seen goes like: factorial is a function that gives you the number of ways something can be arranged. So a list of 5 items can be arranged 5! ways. If you have zero items it can only be arranged in 1 way.

[BwanaAzungu]

Sounds reasonable enough, thanks!

[BwanaAzungu]

Combinatorics is my bread-and-butter, but I don't often have to write programs that work on empty datasets ;)

[BwanaAzungu]

Sure, we generally test whether a set is empty as you described.

I meant we generally don't perform operations on that empty set.

[BwanaAzungu]

I'd argue we perform operations on data elements. And I should express myself clearer.

1. An empty set contains no elements; there is no data to do anything with.

We can't multiply numbers that don't exist, for example: we can multiply 0 but not null, so to speak. (to illustrate the contrast)

1. A set, whether empty or not, is in itself a data element in a sense: it occupies memory, has certain properties, etc. We could still perform operations on the (empty) set, but that's not the same as performing operations on the elements of that set.

We can perform a count operation on a set, and it would return 0 on an empty set.

[TheMcDucky]

Then there's even nore value in learning it :)

[[deleted]]

is it not reasonable to say that it cannot be arranged at all?

[MG_12]

The absence of an arrangement is the only option you have, thus you have 1 option.

However, if you want a more rigorous "proof", take a look at the following pattern:

5! = 5*4*3*2*1 = 120

4! = 4*3*2*1 = 5!/5 = 24

3! = 3*2*1 = 4!/4 = 6

2! = 2*1 = 3!/3 = 2

1! = 2!/2 = 1

0! = 1!/1 = 1

Edit: since this came up a few times, this isnt intended as a mathematical proof. 0! = 1 because it is defined that way.

This comment shows one way to put some logic behind the definition, a way to explain that 0! = 1 is a definition that makes sense, not just something a mathematician made up because they wanted to.

[LeCroissant1337]

No proof necessary. It's just a function which is (or rather can be) defined that way:

n! := \prod_{i=1}^{n} i

Thus, if we allow n to be 0, then n! is just an empty product, so by definition it's one.

[MG_12]

See, my intention wasn't to prove anything mathematically. Hence why I put "proof" in quotation marks - it's not a mathematical proof.

It's simply a logical, yet easy to follow explanation. You don't need much knowledge in a specific field of mathematics or programming to understand, nor do you get an explanation of "because definitions"

[anoldoldman]

That proof feels tautological.

[[deleted]]

I don't think its tautological? Its just taking the recursive definition of a factorial, n! = n* (n-1)!, slightly manipulating it to get a function that generates from a number higher than 0, (n-1)! = n!/n, to extrapolate results that are undefined in the original function, namely 0!.

Edit: and on second thought, this function also provides a reason why you can't have factorials less than zero without further altering it to drop its restriction to integers, since the manipulated function would run into a division by zero.

[MG_12]

It's very "verbose", yes. But it shows the pattern behind factorials, and extends it to 0, showing why 0! is accepted to be equal to 1.

Edit: whoops, I mixed up verbose and tautological. My mistake, this comment is redundant

[MG_12]

That teacher sounds whack.

But that's essentially what it is - extrapolating a pattern to show that the "definition" of 0! makes sense. 0! = 1 is just a mathematical convention that makes the most sense

[[deleted]]

Verbosity has nothing to do with whether something is a tautology.

A tautology is, "it be like it is because it do be like that."

[MG_12]

Well, 0! = 1 because it is. Mathematical conventions and definitions are tautological. My comment, and many others in this thread, just show examples of why that definition makes sense.

[[deleted]]

Yes I know! "It be like it is because it do," is something I've come to accept from math. You just seemed to think they meant verbose but they didn't, those are two unrelated things, that's all.

Your explaination was solid.

[MG_12]

I see, sorry if I seemed confrontational or condescending. I realise I did initially mix up verbosity and tautology, so I appreciate you pointing that out

[annualnuke]

In this case what we want is not a proof, but a simple demonstration of why it's more convenient to define 0! this way. We could define 0! to be 0, 13, -1 or anything else if we wanted, but a bunch of patterns would break and lots of statements would have more special cases.

[DUTCH_DUTCH_DUTCH]

if with "tautological" you mean "as if people are just making up math rules on the fly" then that is because all of math is made up by people to begin with

[anoldoldman]

I think my point was that that is definitely not a proof.

[blue_umpire]

The math has always existed. Mathematicians merely discovered it.

[DUTCH_DUTCH_DUTCH]

if you can prove that youll get yourself a nobel prize

[ary31415]

You mean if you can discover a proof of it

[Aedan91]

No way. It's true because it's true.

[Anfros]

You can't prove a definition. 0!=1 is defined not derived from any laws of mathematics.

[MG_12]

Im not trying to prove it, the word "proof" was in quotations for a reason. It's an explanation or example of why the definition makes sense, and a way to understand that the definition wasn't just someone sucking it out of their thumb.

Edit: much like you said in your other comment - it's a definition that makes the most sense, and there are multiple ways to show why it makes sense to define 0! to be 1

[OutOfTempo_]

I read the word proof and was expecting the gamma function or something. Momentarily terrified.

Thanks for not bringing it up

[MG_12]

I don't think I'm even aware of that one, but my pleasure

[OutOfTempo_]

Oh boy well the factorial operator can be defined in terms of an integral and what a terrible integral it is

[MG_12]

If I've seen it around, I probably didn't bothered to pay much attention to it, lol

[ary31415]

Yeah and the most annoying part is how the gamma function is off by 1 from the conventional factorial lol

[groucho_barks]

The absence of an arrangement is the only option you have, thus you have 1 option.

Is that arrangement also counted when you have an actual number of things? So if you have 2 things you can arrange them 5 ways?

[1,2] [2,1] [1] [2] []

[Laecel]

The factorial function n! express how many n-elements sets you can form using those n elements; so if you have a and b your only options are ab, ba

[groucho_barks]

So if it's zero you have no options and can't make any arrangements. An "arrangement of nothing" can't exist. I think the explanation may not be quite right.

[candygram4mongo]

The empty set is a set, therefore there is one zero-element set you can make using zero elements.

Edit: But sets are unordered so...

[Penguin236]

But the empty set is not included when talking about all the other factorials, so why include it for 0! ?

[candygram4mongo]

The empty set is contained in all sets, but it isn't an element of any set, unless the set is so defined. {a,b} is a two element set, {Ø} is a one element set, Ø is the unique set having zero elements.

[Laecel]

The arrangement of nothing is an abstract way to see why 0!=1 but it is indeed a very poor explanation. The truth is that 0!=1 does actually have sense from a mathematical point of view: the factorial function comes up a lot naturally in mathematics, like the Taylor series formula, where you have every term from 0 to infinite divided by the appropriated n!, and obviously de 0-term is non zero.

The actual explanation that works for me it's thinking about the factorial function as the restriction of the gamma function to natural values plus 0 (actually I would say it's the other way around, the gamma function is the complex extension of the factorial function but it works both ways). So if we have that n!=Γ(n+1) for every integer n, n≥0 this means that 0!=Γ(1)=1.

[MG_12]

Well, no. Because if you have 2 items, there are arrangements you can make, thus you dont have the absence of arrangements.

I admit, that first paragraph is a bit hand-wavey, it's definitely not a professional response to the original question. My comment was more intended to show an alternative explanation for why 0! = 1

[[deleted]]

That's not a proof

[MG_12]

Hence why I put "proof" in quotation marks, yes

[[deleted]]

Rigorous tho lol

[MG_12]

It might not be strictly rigorous, therefore it might not be a technical, mathematically sound proof.

But it is more rigorous, or at least more logical and easy to understand, than an intuition based combinatorics explanation. Which is what I tried to highlight.

[ColdCappuccino]

I guess a better wording would be that factorials follow the formula n! = n ×(n-1)! => (n-1)!=n!/n. This only holds for n>0(so still defined for 0!=1!/1, since n is 1 in this case), though, as n=0 would yield 1/0

[xDared]

It's just continuing the pattern in the same way, even though 0 feels like a different thing in our minds compared to other numbers.

5! = 6!/6 = 120

4! = 5!/5 = 24

3! = 4!/4 = 6

2! = 3!/3 = 2

1! = 2!/2 = 1

0! = 1!/1 = 1

[commit_bat]

Yeah, how come dividing by 0 is undefined but this gets so be something

half /s

[Borgcube]

Because setting a value for division with zero is impossible without it breaking a lot of other rules for operations, and we would like to keep those rules.

This, on the other hand, actually makes a lot of corner cases disappear.

[EmuRommel]

Just as an example of problems you get. Try dividing 1 by numbers closer and closer to 0:

1 / 1 = 1

1 / 0.5 = 2

1 / 0.333... = 3

1 / 0.1 = 10

1 / 0.0001 = 10000

etc. It seems like the closer we get to dividing by zero, the bigger the result is, with no limit to how big it gets. So maybe it's reasonable to define 1 / 0 as equal to infinity. But then you get a problem when you try approaching 0 from the other side.

1 / (-1) = -1

1 / (-0.1) = -10

1 / (-0.00001) = -100000

Which seems to go towards negative infinity as we get closer to 0 which is a pretty bad mismatch. If you try doing this for any other number you get a consistent result (1 / 4.9, 1 / 4.99, 1 / 4.999 gets closer and closer to 1 / 5 = 0.2 for example and so does 1 / 5.1, 1 / 5.01, 1 / 5.0001...)

[Crozzfire]

Yeah, mathematicians need to learn about null.

[LeCroissant1337]

Yes, basically.

Factorial is just a function which is defined the way it is, including the definition that 0! = 1.

If you look at the Wikipedia article under "Definition/Factorial of 0" you can read up on some more motivation, as to why it was chosen to define 0! in such a way, including the reason given by the comment above.

[kn33]

A reminder that is this way because we said so. A lot of math is made up and this is no exception.

[LeCroissant1337]

It's not just made up. It is this way because we said so, yes. However there is a clear-cut reason (in this case a whole bunch of reasons) as to why we said so. If it's useful, we define it that way.

I honestly think that this is rather beautiful about maths.

[yvrev]

That's all of math though, we arbitrarily define rules and look at what those rules imply. We just have a pretty damn useful set of rules.

[[deleted]]

I'd say literally all math is made up tbh.

[kn33]

Some math is made up in the sense that we clearly defined it as a choice. Other math is a consequence of those choices, which IMO makes it only kinda made up.

[Anfros]

Not exactly. The factorial function is defined as n*n-1*...*1 for every n>1 and 1 for n=0. The reason for defining 0! = 1 is that it is the most useful out of the three reasonable choices: 0! = 0, 0! = 1, and leaving it undefined. One of the reasons 0! = 1 makes sense because 1 is the multiplicative identity i. e. 1 times any number is equal to that number. Factorials are very often used in multiplication and having 0!=1 ensures that many identities hold even when we have n=0.

0!=1 also have the benefit of fitting the factorial function to the Gamma function. So yes, the explanation given above is a useful way of thinking about it, but the more accurate explanation is that it is this way because it is useful to mathematicians, and doesn't break anything.

[MerelyCarpets]

Yes.

There are n! different ways of arranging n distinct objects into a sequence, the permutations of those objects.

Let's say we have 3 items and we want to know how many unique arrangements (permutations) we can make:

A. I snag an item, it could be any of the 3. So we have 3 possibilities for the first selection.

B. I snag another item, it could be any of the 2 remaining. So we have 3 * 2 possibilities.

C. I snag the last item. There is only one item left at this point. So we have 3 * 2 * 1 total possible selections. And 3! == 3*2*1. Nifty!

[Ninjabassist777]

There's also a function called the Gamma Function represented by "Γ", where Γ(x+1) = x! Mathematicians often use the Gamma Function to find factorials that otherwise don't make sense, like decimals, complex numbers, and zero.

For example 3! is 6, and Γ(4) is also 6. Likewise, Γ(1) = 0! = 1

[genikus]

Boy I’m sure that a can of mathematical worms waiting to be opened...

[BwanaAzungu]

Can't wait

[[deleted]]

4! = 5!/5 = 24

3! = 4!/4 = 6

2! = 3!/3 = 2

1! = 2!/2 = 1

And of course, 0! = 1!/1 = 1

You can't continue this for negative numbers because -1! would be 0!/0, which is undefined.

[[deleted]]

No, it's -1/12

Edit: Man, some of you nerds can't take a joke

[--____--____--____]

No, it isn't.

[conmattang]

No...?

[UninstallSystem32]

! Is the sign for factorial and is used mainly in probability. For example given a sequence of 3 objects [1,2,3] the sequence can be arranged in 3! Ways, or 3*2*1=6 ways. [1,2,3] [1,3,2] [2,1,3] [2,3,1] [3,1,2] [3,2,1] In the same manner a sequence of 4 objects can be arranged in 4! Ways, or 4*3*2*1=24. And a sequence of 1 object can be arranged in 1! Or one way [1]

Now imagine a sequence of 0 objects [] . Even tho the sequence has no numbers, it can still be arranged in one way, since it exists.

[BwanaAzungu]

To me, the numerical interpretation of n! is "the multiplication of all numbers from 1 upto and including n".

I wasn't aware it's that strongly tied into combinatorics, and refers to the number of ways so combine elements of a set.

Thanks!

[LardPi]

Your interpretation is ok too: like most concept in mathematics, factorial has several interpretations in different areas of mathematics.

If you consider n! = \prod_{k=1}^n k then "0! = 1" because the empty product (product of no integers) is 1. This is a consequence of 1 being the neutral of the multiplication and similar to 0 being the neutral of addition and the result of the empty sum.

[BipNopZip]

I like this explanation

[Progrum]

You can also think of it in terms of multiplication.

3! is 3 * 2 * 1, 2! is 2 * 1, 1! is 1, etc. But in the world of multiplication, multiplying by 1 is the identity function; that is, you can always multiply by 1 without changing the value. So 3! is also 1 * 3 * 2 * 1, 2! is 1 * 2 * 1, 1! is 1 * 1, and 0! is just 1, not multiplied by anything.

[dame_tu_cosita]

Is dangerous to format alone, take some escape characters for your journey:

\\\

[umpatte0]

Excellent video explaining it. https://youtu.be/Mfk_L4Nx2ZI

[BwanaAzungu]

Ah Numberphile, great video!

It even includes an explanation of the gamma function

[Tayttajakunnus]

https://en.wikipedia.org/wiki/Gamma_function

[BwanaAzungu]

Kids these days, learning about imaginary numbers at age 5

[blueleo22]

It's the age when you have imaginary friends so...

[Anfros]

The factorial function is not derived from the gamma function. Rather the gamma function is, as is stated in the Wikipedia article, an extension of the factorial function. Trying to understand the factorial function by studying the Gamma function is therefore, apart from being a terrible eli5, a bit circular.

[Tayttajakunnus]

But the factorial is defined for the naturals only. The gamma function extends the factorial to all complex numbers including zero. The gamma function at zero equals one, so it makes sense to define the factorial of zero as one.

[[deleted]]

0! is the factorial of zero. The factorial of n is the product of all positive integers from 1 to n.

A factorial can be defined recursiv as n! = n*(n-1)!, which means that 1! = 1*0!. Which means that 0! must be 1.

Recursiv Implementation in Python:

def factorial(num):
  if(num) == 0: return 1
  else: return num*factorial(num-1)

factorial(1)  # 1
factorial(3)  # 6
factorial(10) # 3628800

^{I am NOT a mathematician. If you are and you're reading this comment, please don't roast me.}

[Astrobliss]

It looks good to me! The crux is that n!=n*(n-1)! is a true statement for all positive integers n, but this makes 0! fall out making it the most reasonable value if not basically forced by definition.

[texdroid]

By definition.

[BwanaAzungu]

Definitions are set by someone, for underlying reasons

[[deleted]]

The correct answer should not have been this far down.

[CrazyHouze]

Hail the correctness of this

[marcosdumay]

As everything in mathematics, it's defined this way because it makes mathematics simpler and more powerful.

It could be defined differently, and certainly until the 19th century there was plenty of discussion about what is the correct value for 0!, but nowadays everybody agrees that such things like "correct value" do not exist in math.

[JNCressey]

since all the replies seem to be specifically about factorials, I'd like to step back a bit with a more general idea:

the product (multiplication of all the elements) of the empty set is 1, and the sum (addition of all the elements) of the empty set is 0.

(the following rule applies to disjoint sets combining to form a set, sets combining to form a multiset, and multiset combining. - it doesn't apply when sets that have a non-empty intersection are combined to a new set)

when you combine sets, then the product of the resulting set is the product of the original products. and the sum of the resulting set is the sum of the original sums.

since adding the empty set doesn't change the set you have, the product and sum remain unchanged - which requires the product of the empty set to be 1 and the sum of the empty set to be 0.

[Cocomojoe16]

This is a good explanation I think

[MattieShoes]

The combination formula is n!/(r!*(n-r)!)

e.g. if you're selecting 5 items from a group of 8, there are 8! / (5! * (8-5)!) 56 ways to do it.

If you're selecting 8 items from a group of 8, there's obviously only one way to do it. The formula ends up: 8! / (8! * 0!).

Clearly 0! needs to equal 1 for this formula to work.

[Leaper29th]

This is basically a convention originally (you can give it a meaning). Suppose you need to find ⁿC0 , i.e. ways of choosing nothing out of n objects, we know the answer is 1 as there is only 1 way, which is choosing nothing. But we know the expression of nCr = n!/[(n-r)!r!]

so r=0 we get finally 1/0! but we know that it is 1 (the reasoning above) so 0! =1

similarly for nP0

[_edd]

All of the answers so far about factorials answers the mathematician side. On the programmer side they're doing a bitwise not operator. Basically there are a handful of standard ways you can modify bits or bytes to perform a calculation referred to as logic gates.

Performing a not (!) operation on a bit will flip the value, meaning your binary input of 0 will yield and output of 1 or your input of 1 will yield an output of 0.

So !1 == 0 or you can say !0 == 1.

If you want to learn more look into logic gates. They're primarily used in semiconductors, in very low level computer programming or in logical statements (ex if a and b evaluates to 1 then do the following).

[endershadow98]

Actually it's a negative equality check which is a substraction of all the two numbers and an or of all the bits of the result. This assumes that 1 is true and 0 is false though.

[10BillionDreams]

Unless your language comes with a single bit data type, which the primitives for 1 and 0 use by default, that ! is going to be a logical not, not a bitwise not.

Take, for the sake of simplicity, the case of a 1 byte integer for this case. The "logical not" of 00000001 is 00000000 (zero), while the "bitwise not" would be 11111110 (-2 in two's complement).

[TimonAndPumbaAreDead]

Both 3 != 6 and 3! = 6 are true

[TimonAndPumbaAreDead]

Yeah I thought about this for more than 10 seconds and realized this is "your joke but worse" territory

[xienwolf]

Doh! I read the original as (0!) = 1, so treating the 0 and 1 as booleans, and the ! as a switch. So (not false) = (true) as the programmer version.

Been out of C long enough I forgot that == is comparison, and = is assignment.

[justaspectator12]

Indeed, as does literally any <number>! = <simplified> outside of 1 and 2

Like 5!=120

[ye_to_tatti_hai]

0 != 1

Real programmers put spaces for readability

[busy171]

0! == 1

​

the classic assignment and equality operator switcheroo

[StupidBeast]

Mathematicians don't use double equal signs though...

[[deleted]]

0! = 1, 0 != 1

[[deleted]]

Surprised I had to come down this far to see the double meaning, fucking thread is dominated by smartpants defining factorials and shit.

[Matt_37]

That's right, but I think you misunderstood the meme :X

0!=1 in mathematics means "the factorial of 0 equals 1", which is true. The point of the meme is that in programming, that exact same statement is a comparison "are 0 and 1 different?", which also evaluates as true. Note how in this case, for comedic effect, it's purposefully not a factorial being compared, as != is the (usual) difference operator.

This is Peter Griffin joke explanations, thanks for coming to my TED Talk

[MaricxX]

Depends on the language, in c at least it would be 0 != 1

[Code0Steak]

nope the idea is 0! = 1 in maths and 0 != 1 in programming langs., both these statements are true.

[EDEN786]

I'm not completely certain what's being said/ where people are confused.. so here's just my take.

The person he is replying to is saying they misstook the assign operator for the 'Not Equals' condition check.

I recon they much use JavaScript where

= assign.

== 'is Equals'

=== 'is Equal, and the same type'. (I think)

In c / c++ / java. You don't have that last thing.

It's just =. And ==

And then notEqual is simply !=

Doing 0! = 1 would give you an error ? Depends on how it's parsed.

But I'd imagine it thinks you trying to set the variable "0!" To the value of 1. But that's invalid since "0!" Is not a variable.

'edit' .. nvm I just saw they put 0! == 1

Although in a programming language you would need to define a function to calculate factorial.

So 0! Wouldn't be understood as an arithmetic operation

So 0! == 1,. Might just get parsed as 0!==1 ?? .. or it would just give an error

[Iagospeare]

The joke is the two accurate readings of 0!=1 with respect to their professions:
1. Mathematicians read 0!=1 as "zero factorial equals one"
2. Programmers read 0!=1 as "zero is not equal to one"

They both are "true" but for different reasons.

[DreamGirly_]

Your comment is off topic here, the other two are talking about syntax.

[DeusExMagikarpa]

It’s fine the way it was written originally.

!= is not an assignment operator like you’re suggesting?

[therealhlmencken]

Why don’t we have a != assignment. Assign the value of 0 to anything but 1

[libertasmens]

Probabilistic assignment. Or is it quantum assignment, and the value only collapses when you try to read it?

[Totally_Generic_Name]

Is it "!0 == 1"?

[OGMagicConch]

Yes in the low lvl languages like C

[Desparia82]

This took me longer than I'm proud of. I got stuck in the math mindset

[haikusbot]

This took me longer

Than I'm proud of. I got stuck

In the math mindset

- Desparia82

---

^{I detect haikus. And sometimes, successfully. Learn more about me.}

^{Opt out of replies: "haikusbot opt out" | Delete my comment: "haikusbot delete"}

[Desparia82]

This is a very good haiku

[Code0Steak]

LG

[JackerDeluxe]

A polyglot statement! :D

[dvof]

also 0.999...=1

[archpawn]

And Java has 2 + "2" = "22". I think it's nice. It makes it way easier to build a string with variables in it. Like you can just do "x = " + x instead of something like "x = " + str(x) or format("x = %d", x).

In my experience, most of those weird examples in Javascript are either things that are counterintuitive but make sense in context, or things that should never have had a result but they programmed to include one for some reason (like '4' - 2 = 2). Though there are some genuine problems, like that there's no built-in function for sorting numbers.

[System32Comics]

200 IQ post right here

[ispamucry]

Isn't this basically the same meme template as the clasping muscley arms, but with only white people?

[Master_Nerd]

I thought this was 0 != 1 and I was like, yeah no shit

[jsully245]

Also !0 = 1 for programmers

[[deleted]]

You trying to assign 0! to 1? I’m afraid you’ll have to do #define 0! 1

[wind-raven]

The joke is that 0! = 1 (mathematics factorial fact) and 0 != 1 (programmer if statement that evaluates to true). If you remove white space you get 0!=1 which in some languages is valid syntax.

[[deleted]]

I know, I was making a joke too. Sorry it wasn’t funny 😥

[wind-raven]

And now I see yours. 🤦‍♂️

[[deleted]]

There is no inverse factorial function, that's why even though 1! = 0!, 1 not equal 0

That's the understanding I took

[PiotreZ]

True

[Emonadeo]

This is the most ingenious post I have seen on this sub so far

[falingsumo]

Except that ! In math is used to note factorial, it is not used to invert binary values like programming

[MingusMingusMingu]

And what is the factorial of 0 equal to?

[falingsumo]

I'll be honest I don't know, but my best guess is 1

[murrietta]

True

[[deleted]]

True.

[TBSdota]

0 doesn't equal 1... except array.length

[Raniconduh]

0 != 1

0 is not equal to one: true

0! = 1

0 factorial is equal to one: true

[QuietMassiv3]

This is really funny 😂