CollectionExpression join

Feature Requests
1

Would love if there were a CollectionExpression function to join the collection (array/set) elements with a delimiter and return a string, like the opposite of split(). For example, if

a = ['an', 'array', 'of', 'elements', 'becomes', 'a', 'string']
>>> hl.eval(a.join(' '))
'an array of elements becomes a string'
2

use hl.delimit:

>>> a = ['an', 'array', 'of', 'elements', 'becomes', 'a', 'string']
>>> hl.eval(hl.delimit(a, ' '))
'an array of elements becomes a string'

I agree this should work as ' '.join(a). I created an issue to track the suggestion: https://github.com/hail-is/hail/issues/9188.