[C++] Add string padding option to determine which side the extra space goes on

[asfimport]

I'm trying to implement R bindings for the compute function "utf8_center" but in cases where there are an odd number of spaces in total, the extra space is added to the left.  However, in R, the extra space is added to the right.

Please can we have another string pad option to determine which side the extra space goes, so I can make the functionality match?

Reporter: Nicola Crane / @thisisnic
Assignee: David Li / @lidavidm

PRs and other links:

• GitHub Pull Request #10639

_{Note: This issue was originally created as ARROW-13234. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
In Python, the extra space is added to the right as well. Perhaps we can simply change the C++ behaviour? @lidavidm

[asfimport]

Antoine Pitrou / @pitrou:

>>> s = "xxx"
>>> s.center(5)
' xxx '
>>> s.center(6)
' xxx  '
>>> s.center(7)
'  xxx  '

[asfimport]

David Li / @lidavidm:
I'll change it to put it on the right, yes.

[asfimport]

Nicola Crane / @thisisnic:
Awesome, thanks!

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 10639
#10639