Fix ordering of integer-named columns.

[ericemc3]

I love pivot and fold fonctions in Arquero, they are so powerful !

I just ran into few small difficulties.
Here is a use case:

t = aq.table({x:['01','01','01','02','02','02'], y:['1','2','3','1','2','3'], z:[123,256,854, 652,734,222]})

x	y	z
01	1	123
01	2	256
01	3	854
02	1	652
02	2	734
02	3	222

I pivot that table:

t.groupby(0).pivot(1,2)

The problem is that x is now located on the right, i'd like it to stay in the first position.

1	2	3	x
123	256	854	01
652	734	222	02

I am trying all these variants, but in vain, x doesn't want to move ;)

t.groupby(0).pivot(1,2).relocate('x', {before:0}).view() ;
t.groupby(0).pivot(1,2).relocate('x', {before:1}).view() ;
t.groupby(0).pivot(1,2).relocate('x', {before:"1"}).view() ;

Maybe i am missing something there. Of course i can write a select.
The fact that new column names are not by default prefixed probably does not help.

My humble suggestions would be:

1. after a pivot, make the groupby columns appear at first
2. add a prefix option in pivot (and fold as well)

For instance:
p = t.groupby(0).pivot(1,2, {prefix:'age_'})

could produce:

x	age_1	age_2	age_3
01	123	256	854
02	652	734	222

and conversely:
p.fold(aq.range(1,3),{as:['y','z'], prefix:'age_'})

would take me back to the original table.

For the moment i use for pivot something like:
p = t.groupby(0).pivot({ d: d => 'age_' + d.y },2, {prefix:'age_'})

But after a fold i have to write something like this this, which i find not very elegant:
.derive({y: d => op.substring(d.y,4)})

cf. for inspiration (and old habits):
https://tidyr.tidyverse.org/reference/pivot_longer.html (aka fold) and names_prefix option
https://tidyr.tidyverse.org/reference/pivot_wider.html (aka pivot) and names_prefix option

[jheer]

Thanks! This bug arises from JavaScript's built-in key ordering semantics for objects (integers always come first), which Arquero uses currently but of course needs to circumvent. I'm aware of the issue (I bumped into it more or less the same way you did!) and have started work on a fix.

[jheer]

Fixed and released in v1.3.0.