[R] Implement bindings for lubridate::tz

[asfimport]

This can be achieved via strftime

Reporter: Nicola Crane / @thisisnic
Assignee: Dragoș Moldovan-Grünfeld / @dragosmg

Related issues:

• [R] Add a type method for Expression (Testing discovered)

PRs and other links:

• GitHub Pull Request #12357

_{Note: This issue was originally created as ARROW-14817. Please see the migration documentation for further details.}

[asfimport]

Weston Pace / @westonpace:
I don't think you even need strftime. For example, strftime will run an operation on every item in the array. So if you have an array with 1 million elements you will string-format 1 million items.

On the other hand, in Arrow, we know the time zone will be consistent across the entire array. So we only need to take the time zone from the array's dtype. For example, in python, I could do...

>>> a = pa.array([0, 1, 2], type=pa.timestamp('us', 'America/Denver'))
>>> print(a.type.tz)
'America/Denver'

Although, if you then wanted to take that value and feed it further in the query engine...I'm not sure what the right way to go about that would be. Basically you should know the value at query production time so I think you can just feed it in as a constant value in the query plan. For example...

SELECT score, 'America/Denver' FROM my_table

[asfimport]

Jonathan Keane / @jonkeane:
Issue resolved by pull request 12357
#12357