Request for NavigableTable

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We have Table, in which everything is unsorted,
and we have RowSortedTable, which gives us sorted lookup-access to rows but not 
to columns (even though the column maps are sorted).

I'm after something that provides sorted lookup through columns, perhaps in the 
sense that I could get a NavigableMap<C, V> for a row, and be able to do things 
like table.row(rowKey).floorEntry(columnKey).getValue(). Obviously this 
generalises to full navigable access over the rows and columns.

The use case here is to represent data that changes through time, so C is Date, 
for example. I'm effectively storing key-value (R-V) pairs where the value 
depends on the time. I can't represent this as RowSortedTable<Date, K, V> 
because the values for all keys don't change at the same time.

Is this something that fits into current plans for Table?

Original issue reported on code.google.com by joe.j.kearney on 3 Feb 2012 at 9:30

[GoogleCodeExporter]

> The use case here is to represent data that changes through time, so C is
> Date, for example. I'm effectively storing key-value (R-V) pairs where the
> value depends on the time. I can't represent this as RowSortedTable<Date, K,
> V> because the values for all keys don't change at the same time.

I don't quite follow why changing some values separately would be a poor fit 
for RowSortedTable<Date, K, V>.

Original comment by cpov...@google.com on 3 Feb 2012 at 6:06

• Added labels: Package-Collect, Type-Enhancement

[GoogleCodeExporter]

Because the rowMap for any given date would need to know about values from 
other rows. I wasn't clear that I'm talking about a possibly sparse time 
series: in the example each row corresponds to a changing series of values, 
where the date specifies when the value becomes the 'active' one for that row. 
There's not necessarily any expectation of uniformity of this scheduling - the 
value for series A might change independently between consecutive changes of 
the value of B.

Toy example: suppose I have time series like this in a RowSortedTable, with 
times as the row keys, showing the last time we decided on our current 
favourite fruits:

Time | A(time)   | B(time)
1    | Apple     | Banana
2    | Pear      |
3    | Raspberry |
4    | Grape     | Orange

so B's favourite fruit is the same from time 1 to time 3. Unless I store 
mappings for every time value, there's no way to find out B's favourite 
(Banana) at time 3, for example.

Whereas, if you represent this the other way around, with row sorted columns:

Time    | 1      | 2    | 3         | 4      |
A(time) | Apple  | Pear | Raspberry | Grape  |
B(time) | Banana |      |           | Orange |

you can look up by row, then pick the floorKey(3) to get the most recent value.

Original comment by joe.j.kearney on 3 Feb 2012 at 6:32

[GoogleCodeExporter]

I'm going to say that this would be...nontrivial, implementation-wise, I'm 
pretty sure.  Making an API fit the Navigable spec is a lot of work, just 
because it's so many methods.

I'd be willing to do it, but I just want to say that...

Original comment by wasserman.louis on 3 Feb 2012 at 10:30

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Original comment by wasserman.louis on 5 Feb 2012 at 9:43

• Changed state: Duplicate

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Is the plan to update the other bug to refer to TreeBasedTable as well as 
TreeMultimap?  The challenges for this one seem a bit steeper but I'm sure well 
within your capabilities :)

Original comment by cpov...@google.com on 5 Feb 2012 at 10:33

[GoogleCodeExporter]

Oh dear.  These are not actually duplicates, are they.

It's so easy to mix up Tables and Multimaps!

Original comment by wasserman.louis on 5 Feb 2012 at 10:54

• Changed state: Triaged

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Original comment by fry@google.com on 16 Feb 2012 at 7:18

• Changed state: Acknowledged

[GoogleCodeExporter]

Issue 905 has been merged into this issue.

Original comment by fry@google.com on 13 Mar 2012 at 6:41

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Original comment by kevinb@google.com on 30 May 2012 at 7:43

• Added labels: Type-Addition
• Removed labels: Type-Enhancement

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Original comment by kevinb@google.com on 22 Jun 2012 at 6:16

• Changed state: Research

[GoogleCodeExporter]

This issue has been migrated to GitHub.

It can be found at https://github.com/google/guava/issues/<id>

Original comment by cgdecker@google.com on 1 Nov 2014 at 4:14

• Added labels: MigratedToGitHub

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Original comment by cgdecker@google.com on 1 Nov 2014 at 4:18

• Changed state: Migrated

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Original comment by cgdecker@google.com on 3 Nov 2014 at 9:08

• Added labels: Restrict-AddIssueComment-Commit