This code would run a lot faster as a hash table look up.
Can you imagine being a TA and having to grade somebody’s hw and you get this first thing? lmao
This joke was not written by the dude pictured. The author wrote a book of funny code jokes.
Y’all laugh but this man has amazing code coverage numbers.
def is_even(n: int) -> bool: if n < 0: return is_even(-n) r = True for _ in range(n): r = not r return rTo be fair, the question is “Write a function that simultaneously determines if the number is even and works as a timer”
This is YandereDev levels of bad.
this is yanderedev.
Plot twist: they used a script to generate that code.
You don’t get it, it runs on a smart fridge so there’s no reason to change it
- a smart fridge’s monitor
def even(n: int) -> bool: code = "" for i in range(0, n+1, 2): code += f"if {n} == {i}:\n out = True\n" j = i+1 code += f"if {n} == {j}:\n out = False\n" local_vars = {} exec(code, {}, local_vars) return local_vars["out"]scalable version
Not even else if? Damn, I guess we’re checking all the numbers every time then. This is what peak performance looks like
O(1) means worst and best case performance are the same.
I hope that the language’s
ints are at most 32 bits. For 8 bits it could even be written by hand & the source code for a 32 bit version would only take upavg_line_len * 4GiBspace for the source code of the function. But it might take a bit of time to compile a version that supports the full range of 64 or 128 bit ints.My mate, Paul, says all numbers after 700 repeat so we can stop there.
We just give them different names so you think they’re going up.
I’ll join in
const isEven = (n) => !["1","3","5","7","9"] .includes(Math.round(n).toString().slice(-1))I’ve actually written exactly that before, when I needed to check the lowest bit in an SQL dialect with no bitwise operators. It was disgusting and awesome.
bool isEven(int value) { return (int)(((double)value / 2.0) % 1.0) * 100) != 50; }That code is so wrong. We’re talking about Jason “Thor” Hall here—that function should be returning 1 and 0, not booleans.
If you don't get the joke...
In the source code for his GameMaker game, he never uses
trueorfalse. It’s always comparing a number equal to 1.Frankly, it’s what I did, too, after coming out of Uni-level C.
My code was goddamn unreadable.
It’s the same for a lot of people. Beginners are still learning good practices for maintainable code, and they’re expected to get better over time.
The reason people are ragging on PirateSoftware/Jason/Thor isn’t because he’s bad at writing code. It’s because he’s bad at writing code, proclaiming to be an experienced game development veteran, and doubling down and making excuses whenever people point out where his code could be better.
Nobody would have cared if he admitted that he has some areas for improvement, but he seemingly has to flaunt his overstated qualifications and act like the be-all, end-all, know-it-all of video game development. I’m more invested in watching the drama unfold than I should be, but it’s hard not to appreciate the schadenfreude from watching arrogant influencers destroy their reputation.
I am working with C in embedded designs and I still use 1 or 0 for a bool certain situations, mostly lines level.
For whatever pea-brained reason, it feels yucky to me to set a gpio to true/false instead of a 1/0.
GPIOs are usually controlled by a single bit of a register anyway. Most likely you need to do something like:
// Set high PORTB |= 1 << PINB5; // Set low PORTB &= ~(1 << PINB5);I am a lazy dev (not really, clients always want fast code), so I use the provided HAL libraries 99.9% of the time.
But I have seen code where someone would write something like
gpio_write(PIN_X, true)and it always stood out to me.
I’m partial to a recursive solution. Lol
def is_even(number): if number < 0 or (number%1) > 0: raise ValueError("This impl requires positive integers only") if number < 2: return number return is_even(number - 2)I prefer good ole regex test of a binary num
function isEven(number){ binary=$(echo "obase=2; $number" | bc) if [ "${binary:-1}" = "1" ]; then return 255 fi return 0 }
If your codebase is closed source there’s no risk of that happening, if it’s open source there’s nothing you can do about it.
Either way there’s no use worrying.
Amateur! I can read and understand that almost right away. Now I present a better solution:
even() ((($1+1)&1))(I mean, it’s funny cause it’s unreadable, but I suspect this is also one of the most efficient bash implementations possible)(Actually the obvious one is a slight bit faster. But this impl for
oddis the fastest one as far as I can tellodd() (($1&1)))I’m waiting for a code golf style solution now.
woah your bash is legit good. I thought numeric pretexts needed
(( blah )), but you’re ommiting the $ like an absolute madman. How is this wizardy possibleSee:
man bash, “Compound Commands” and “Shell Function Definitions”Oh I see it, but for some reason I was taught to always use
(( arith ))instead of(( arith ))and I guess I’m just wondering what the difference isThe difference is that
((is a “compound command”, similar to[[(evaluate conditional expression), while(( ))is “aritmetic expansion”. They behave in almost exactly the same way but are used in different contexts - the former uses “exit codes” while the latter returns a string, so the former would be used where you would expect a command, while the latter would be used where you expect an expression. A function definition expects a compound command, so that’s what we use. If we used(( ))directly, it wouldn’t parse:$ even() $((($1+1)&1)) bash: syntax error near unexpected token `$((($1+1)&1))'We would have to do something like
even() { return $(($1&1)); }(notice how this is inverted from the
((case -((actually inverts 0 -> exit code 1 and any other result to exit code 0, so that it matches bash semantics of exit code 0 being “true” and any other exit code being “false” when used in a conditional)But this is a bit easier to understand and as such wouldn’t cut it, as any seasoned bash expert will tell you. Can’t be irreplaceable if anyone on your team can read your code, right?
I can’t think of many use-cases for
((. I guess if you wanted to do some arithmetic in a conditional?if (( $1&1 )); then echo "odd!"; else echo "even!"; fiBut this is pretty contrived. This is probably the reason you’ve never heard of it.
This
((vs.(( ))thing is similar to how there is(compound command (run in a subshell), and$( )(command substitution). You can actually use the former to define a function too (as it’s a compound command):real_exit() { exit 1; } fake_exit() ( exit 1 )Calling
real_exitwill exit from the shell, while callingfake_exitwill do nothing as theexit 1command is executed in a separate subshell. Notice how you can also do the same in a command substition (because it runs in a subshell too):echo $(echo foo; exit 1)Will run successfully and output
foo.((being paired with$((, and(with$(, is mostly just a syntactic rhyme rather than anything consistent. E.g.{and${do very different things, and$[[just doesn’t exist.Bash is awful. It’s funny but also sad that we’re stuck with it.
