I would like to define a vector of anonymous functions that take a single parameter, then map a parameter x across this vector, returning an array of the results of f(x) for each index. Is this possible in Dyalog?
I ask because my naive attempt at creating such a closure vector:
fs ← {⍵×2} {⍵×4...
Dyalog APL doesn't directly support arrays of functions, but you can get close using an array of namespaces containing functions. For example: nss←⎕NS¨'' '' '' nss.⎕FX ⍉∘⍪¨'f←{⍵×2}' 'f←{⍵×4}' 'f←{2+⍵×3}' nss.f 11 22 44 35
@EriktheOutgolfer Thanks, done. Well, the reason for the ⍉ is that ⎕FX expects a matrix, and we only have one line of code. So ⍉⍪ to turn each character vector into a 1-row matrix. A bit ugly, but it works.
@MortenKromberg btw I think that you can also do something along the lines of (⊢⍴⍨1,⍴) instead of that ugliness because we're not going for terseness there ;)
@JackHenahan Equivalent in ⎕ML≤1, yes. Using ⍤`, no. Just subtract less than 1 from the axis. This notation is more precise as you are really inserting a new axis before axis 1:
I have two dataframes with two columns each
event: column names --> "District" "City"
villages: column names --> "District" "Village"
"event" dataframe has district names and events happening in its district villages. The "City" column is a sentance data which has village names of correspon...
@Adám Thanks for looking into it. I guess I'll just have to get used to it, in that case. Just feels weird, especially when ⍤ is ostensibly used in place of index notation. Oh, well :)
@JackHenahan I also thought that ⍤ replaces bracket-axis, but it really doesn't. It instead provides a neat and generalised way to "pair up" the cell-sizes of argument(s) and function, something that the bracket axis can't do as well on dyadic function application, and not at all on application of user defined functions.
@JackHenahan :-) APL is only a bit over half a century old. Its prime time has yet to come, but I do believe the world is slowly getting ready. We also have a few things to fix up before show time… Let me know if I (or Dyalog) can be of help with anything.
I have two dataframes with two columns each
event: column names --> "District" "City"
villages: column names --> "District" "Village"
"event" dataframe has district names and events happening in its district villages. The "City" column is a sentance data which has village names of correspon...
