if i have a column of list of strings, is there a way I can apply the str expressions on the values in my column of lists?

Not at the moment… What do you think is a good API?

df = df.with_column(
    "mapped",
    df["list_of_strings"].list.eval(daft.element().str.left())
)

What about this API?

I was thinking of df = df.with_column( "mapped", df["list_of_strings"].list.apply(str.left()) ) where the function applied to the element is an available expression and matches the type in the expression as well

Yeah the problem is that

str.left()

is not possible since

str

isn’t a type we control… Another possible approach is maybe a lambda:

.list.apply(lambda item: item.str.left())

I’m afraid this gets a little confused with our current

.apply

which is a convenience method over UDFs though

Ah I see.. i was keeping str from the syntax used in the expressions so i would expect that it can also be used for a list within a list etc.. 😅

Yeah

str

in Python is just…. Python

str

so it wouldn’t work 😢

That's true

Ok we’ll come up with something here. Seems like a pretty common ask

Expression.str.left?

Nope, for

.list.apply

Got it!