[Python-ideas] Vectorization [was Re: Add list.join() please]

[MRAB]

On 2019-02-03 22:58, David Mertz wrote:
>      >>> len(v)  # Number of elements in the Vector `v`
> 
> 
> Agreed, this should definitely be the behavior.  So how do we get a 
> vector of lengths of each element?
> 
>      >>> # Compute the length of each element of the Vector `v`
>      >>> v.apply(len)
>      >>> v @ len
> 
> 
> Also possible is:
> 
>      v.len()
> 
> We couldn't do that for every possible function, but this one is special 
> inasmuch as we expect the items each to have a .__len__() but don't want 
> to spell the dunders. Likewise for just a handful of other 
> methods/functions.
> 
> The key different though is that *I* would want to a way to use both 
> methods already attached to the objects/items. in a vector and also a 
> generic user-provided function that operates on the items. I guess you 
> disagree about "method pass-through" but it reads more elegantly to me:
> 
>      >>> # Replace all "a" by "b"
>      >>> v.apply(lambda s: s.replace("a", "b"))
>      >>> v @ (lambda s: s.replace("a", "b"))
> 
> 
> Compare these with:
> 
>      v.replace("a", "b")
> 
> Since we already know v is a Vector, we kinda expect methods to be 
> vectorized.  This feels like the "least surprise" and also the least 
> extra code.  Moreover, spelling chained methods with many .appy() calls 
> (even if spelled '@') feels very cumbersome:
> 
Do they need multiple uses of apply and @?

> (A) v.apply(lambda s: s.replace("a", "b")).apply(str.upper).apply(lambda 
> s: s.count("B"))
 >
v.apply(lambda s: s.replace("a", "b").upper().count("B"))

> (B) v @ lambda s: s.replace("a", "b") @ str.upper  @ lambda s: s.count("B")
> 
v @ lambda s: s.replace("a", "b").upper().count("B")

> (C) v.replace("a","b").upper().count("B")
> 
> Between these, (C) feels a heck of a lot more intuitive and readable to me.
> 
[snip]