Edward Banner

slingin' sexps

[Edward Banner @EdwardBanner]

Virtual edit mode in vim (set ve=all) is like anti-gravity mode

[Edward Banner @EdwardBanner]

Workshopped a tacit/point free solution with Claude

⊣×⌈∘(0.5+÷⍨)

[Edward Banner @EdwardBanner]

🔥 https://t.co/frk3Nf7Lm4
🟢 Nearest Multiple

{⊃(⍺×mults)[⍋|⍵-⍺×mults←(⌊⍵÷⍺)(⌈⍵÷⍺)]}

[Edward Banner @EdwardBanner]

Claude came up with a better solution

{⍺×⌊0.5+⍵÷⍺}

[Edward Banner @EdwardBanner]

Would be cool if a regex library knew how to match /[0-255]\.[0-255]\.[0-255]\.[0-255]\./

[Edward Banner @EdwardBanner]

🥷 https://t.co/kmBL6ov5zJ
🟢 Program to validate IP address

{1 1 1 1≡256>(⍕¨⍳256)⍳('.'∘≠⊆⊢)⍵}

[Edward Banner @EdwardBanner]

This was the nicest plausible-looking Perl solution I could come up with (Untested & Generated by Claude™)

use Number::Range::Regex qw(range_to_regex);

my $N = range_to_regex(0, 255);
my $IP = qr/^$N\.$N\.$N\.$N/;

sub is_valid_ip {
return $_[0] =~ $IP;
}

[Edward Banner @EdwardBanner]

Not handling the budget part of the problem, but I thought it's a cute way to find the best buy and sell day

[Edward Banner @EdwardBanner]

🔥 https://t.co/frk3Nf7Lm4
🟢 Max Profit

{⌈/(⊃-(⊃⌽))¨⊃,/⍵∘{⍵,/⍺}¨1+⍳(≢⍵)-1}

[Edward Banner @EdwardBanner]

Pretty cool that sliding windows are a primitive built into APL in a first class way

[Edward Banner @EdwardBanner]

🥷 https://t.co/9Zghj2WCt5
🟢 Find Peak Element

⎕←⊃⍸{(⍵[1]<⍵[2])∧⍵[2]>⍵[3]}¨3,/arr

[Edward Banner @EdwardBanner]

The indexing with a matrix '.#'[1+grid] part is kind of blowing my mind

[Edward Banner @EdwardBanner]

📊 https://t.co/iR4nY7y2sk
🟢 Fox And Snake

grid←n m⍴0
l r←(4×⍳n) (2,2+4×⍳n)
grid[⍸2|⍳n;]←1
grid[(l[⍸l≤n],¨1),(r[⍸r≤n],¨m)]←1
⎕←'.#'[1+grid]

[Edward Banner @EdwardBanner]

Was disappointed to find the picture is not as nice in Haskell earlier this year

[Edward Banner @EdwardBanner]

🔥 https://t.co/frk3Nf7Lm4
🟢 Bucket Fill

{
grid (row col) color←⍵
mask←grid=grid[row;col]
fill←1@(⊂row,col)⊢(⍴grid)⍴0
result←{mask∧⍵∨⊃∨/(1⌽⍵)(¯1⌽⍵)(1⊖⍵)(¯1⊖⍵)}⍣≡⊢fill
grid[⍸result]←color
}

[Edward Banner @EdwardBanner]

Also pleased to find that fixed points are very clean to do in APL

[Edward Banner @EdwardBanner]

Too bad sort doesn’t work directly on strings it seems

[Edward Banner @EdwardBanner]

🔥 https://t.co/frk3Nf7Lm4
🟢 Kaprekar's Routine
({⍵[⍒⍵]}⍢⍕)-({⍵[⍋⍵]}⍢⍕)

[Edward Banner @EdwardBanner]

According to Claude, in TCL integers are just strings so there’s no conversion step necessary

proc digitDiff {n} {
set digits [split $n ""]
expr {
[join [lsort -decreasing $digits] ""]
-
[join [lsort $digits] ""]
}
}