I saw answer in this question How to use rank operator instead of each in APL how to build own Each operator using Rank ⍤.
Monadic Each f¨x can be represented as {⊂f⊃⍵}⍤0⊢x
Dyadic Each x f¨y can be represented as x{⊂(⊃⍺)f(⊃⍵)}⍤0⊢y
In terms of this please answer following questions:
Why Eac...
In Dyalog APL I can use the function ⎕TS to get the current year, month, day, hour, minute, second etc, but is there a way to get the current timestamp in seconds from e.g. 1970-01-01 (Unix timestamp)?
@Sherlock9 here's an idea: if we have a list of results candidates of length L-1, we could build the list for L by appending the elements of m to old candidates in all possible ways. this can be optimised by keeping only candidates with distinct sums that are ≤⍵. so, starting with candidate list ,⊂⍬, after ⍺ steps we'll find a valid result (if it exists) without using the 15+ dimensional ∘.+.
has anybody done tree traversal in gnu apl? my goal is essentially to do the following in gnu-apl, using lambdas as much as possible: https://youtu.be/DsZdfnlh_d0
im starting out building a basic accumulator (that adds 1 to each number): foo ← {{(1+1↑⍵),(foo 1↓⍵)}⍣(~0=⍴⍵)⍵}
however I cant get it to play nice with a left argument empty vector
heres the help page btw:
dyadic operator: Z ← A (F ⍣ G) B (Power Operator) repeat: B ← A F B until (A F B) G B is true (function G)
thx. heres updated (with attempt at left arg) foo ← {⍬{⍺,(1+1↑⍵),(foo 1↓⍵)}⍣(~0=⍴⍵)⊢⍵} foo 1 2 3 2 3 4
although trying to replace the zilde with alpha yields following: foo ← {⍺{⍺,(1+1↑⍵),(foo 1↓⍵)}⍣(~0=⍴⍵)⊢⍵} ⍬ foo 1 2 3 VALUE ERROR foo[1] λ←⍺ λ1⍣(∼0=⍴⍵)⊢⍵ ^
@cannadayr i don't know what you're trying to achieve with ⍺ and ⍬ but it seems the reason for the error is that the function application foo 1↓⍵ doesn't have anything on the left of foo
@cannadayr in dyalog ad hoc recursion is relatively simple with ∇ ("recur" - this is an alias for the function that's currently being executed) and guards ({condition:then ⋄ else}). i'm not familiar enough with gnu apl to make a comparison.
@cannadayr thanks! i haven't been doing any work on it for a while, as i became more interested in k, but luckily newer and more complete apl-like language implementations appeared, like dzaima/apl for instance
@cannadayr the newest k, also known as "shakti" (not yet released), will probably use some non-ascii characters
also k is very different from apl. it's more distant from apl than j is. for instance it only supports scalars and vectors, no matrices (except as vectors of vectors). so, many of the primitive operations in apl don't translate literally to k.
yea, i personally rly like the apl design. I found that after a few months I was starting to think in the character set even in other programming languages.
whenever i look at J/K its difficult for me to parse the overloaded terms (but that might just be one of familiarity)
In Dyalog APL I can use the function ⎕TS to get the current year, month, day, hour, minute, second etc, but is there a way to get the current timestamp in seconds from e.g. 1970-01-01 (Unix timestamp)?
