61
votes
How on earth did llhuii output the Evil Numbers in 42 bytes of Python?
This isn't the same solution as llhuii's, but it's also 42 bytes long.
n=0;exec'print n;n^=(n^n+2)%3/2;n+=2;'*400
Try it online!
Thanks to @JonathanFrech, we're ...
- 210k
58
votes
Tips for golfing in Java
Use interface instead of class.
In java 8, static methods were added to interfaces. In interfaces, all methods are public by ...
- 11.5k
53
votes
Tips for golfing in <all languages>
Write an explanation of your code
Writing an explanation forces you to thoroughly look at each part of your code again and to make your thoughts and choices in writing a certain passage explicit. In ...
- 26.1k
45
votes
How on earth did llhuii output the Evil Numbers in 42 bytes of Python?
Getting 39 bytes
This is an explanation of how I got a 39-byte solution, which Dennis and JonathanFrech found separately as well. Or, rather, it explains how one could arrive at the answer in ...
- 144k
43
votes
Tips for golfing in C
Use lambdas (unportable)
Instead of
f(int*a,int*b){return*a>*b?1:-1;}
...
qsort(a,b,4,f);
or (gcc only)
...
- 7,467
41
votes
Tips for golfing in <all languages>
Use unary ~ for x+1 and x-1
This trick applies to languages that have a unary bitwise ...
- 68.1k
41
votes
Tips for golfing in 05AB1E
Since it wasn't part of the Wiki on 05AB1E's GitHub pages (I think it should), I'm just gonna add it here now that I better understand it myself.
How to use the dictionary?
05AB1E has the following ...
- 123k
36
votes
Accepted
Tips for Creating/Maintaining a Golfing Language
Here are some suggestions. Sorry that this partially overlaps with other answers, which have been posted as I was writing this.
Design process
One possibility (by all means not the only one) to ...
- 104k
35
votes
Tips for golfing in Jelly
String compression
If you're looking for a more optimized/automatic string compressor, try this one.
Try it online!
A compressed string looks like “...», where ...
- 68.1k
32
votes
Tips for restricted source in Python
Avoid "normal" letters
Identifiers are normalized by the Python 3 parser. This implies that cursive (Unicode) letters such as 𝓪𝓫𝓬𝓓𝓔𝓕 are interpreted ...
- 104k
29
votes
Accepted
How to solve the LCM in 50 bytes of Python
My solution to 50 bytes:
v=1
for x in input().split()*6**6:v+=-v%int(x)
print(v)
Explanation
The solution itself is relatively simple, but finding it was ...
- 22.3k
28
votes
Tips for golfing in Python
Assignment expressions
Assignment expressions are a powerful language feature introduced in Python 3.8 (TIO). Use the "walrus operator" := to assign a variable ...
- 144k
28
votes
27
votes
Tips for golfing in Python
Common helper functions
These are some golfed implementations of number theoretic functions that come up in challenges a lot. Many of these are due to xnor, especially the “Wilson’s theorem prime ...
- 68.1k
26
votes
Tips for code-golfing in C#
Instead of
bool a = true;
bool b = false;
do
var a=0<1;
var b=1<0;
If you need multiple variables, use this (...
- 3,762
26
votes
Tips for Golfing in Brain-Flak
Use the Third Stack
If you have read the title you might be a bit confused. Surely there are only two stacks in Brain-Flak? However I assure you that it exists and it is one of the most powerful if ...
- 96.6k
25
votes
Tips for golfing in Python
Printing a string without a trailing newline in Python 3
Suppose you have a string s, and need to print it without a trailing newline. The canonical way of doing ...
- 61.7k
25
votes
Tips for golfing in Python
The shortest infinite for comprehension
You may know the trick to easily create an infinite generator using the two-argument form of iter:
...
- 23.3k
25
votes
Tips for golfing in JavaScript
Array sum / product / quotient
ES5: 17 bytes
eval(a.join('+'))
ES6: 15 bytes
eval(a.join`+`)
Of course you can swap the <...
- 2,554
25
votes
Tips for golfing in <all languages>
use - instead of !=
for numeric comparisons:
If a equals b, a-b results in ...
- 14.6k
25
votes
Tips for golfing in Mathematica
Lists with repeated values
This is quite a common vector to work with:
{0,0}
It turns out this can be shortened by a byte:
...
- 196k
25
votes
Accepted
Is it possible to make a clamp function shorter than a ternary in JS?
20 bytes
For reference, this is the original version without whitespace and without naming the function:
n=>n>0?n<255?n:255:0
Try it online!
19 bytes
We ...
- 189k
25
votes
Tips for restricted source in Python
Avoid Numbers with Booleans
When performing arithmetic operations on Booleans, Python treats them as if they are the numbers 1 and 0. So for example
...
25
votes
Accepted
Can `a?b<c:b>c` be shortened in Javascript?
Yes, it can be shorter!
c-b<a^a beats a?b<c:b>c by 2 bytes. My tests show that it works for any integer, including ...
- 22.3k
24
votes
Tips for golfing in JavaScript
Abuse literals
The recent sample: Check whether "c" is uppercase or lowercase, doesn't matter if not letter
...
- 20.7k
24
votes
Tips for golfing in R
Some very specific golfing tips:
if you need to extract the length of a vector, sum(x|1) is shorter than length(x) as long as <...
- 1,673
24
votes
Tips for golfing in Rust
Use closures instead of functions
A closure:
|n|n+1
is shorter than a function:
fn f(n:i32)->i32{n+1}
Closures longer ...
- 71.4k
24
votes
Accepted
Brainf*ck Loop Problem
27 24 bytes
++[<++[++<]>>>+]<[-<-.>]
Spent a whole day basically writing up a brute forcer and watching the results come in. Now I can ...
- 61.7k
24
votes
Tips for creating polyglots
Exploit comment symbols
A simple way to create a two-language polyglot is to have the code divided in two parts as follows:
The first part does the actual work in language A, is harmless in language ...
- 104k
Only top scored, non community-wiki answers of a minimum length are eligible