Timeline for KeyTake, KeyDrop fail with Transpose in Dataset
Current License: CC BY-SA 3.0
10 events
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| Apr 13, 2017 at 12:55 | history | edited | CommunityBot |
replaced http://mathematica.stackexchange.com/ with https://mathematica.stackexchange.com/
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| Nov 16, 2016 at 19:38 | comment | added | alancalvitti | That's good news, gives hope for a ground-up re-implementation of Dataset's formatting based on the built-in expression manipulation (which in addition might allow pattern matching). For example, in v10 formatting workarounds using Framed, Column, Grid etc, within and outside Dataset allowed a lot of freedom, so it's feasible. Unfortunately v11 broke a lot of these. | |
| Nov 16, 2016 at 19:32 | comment | added | WReach |
Type-inferencing is not invoked for ... // Query[...] where the left-hand side is a non-dataset expression. We can observe this by establishing On[TypeSystem`TypeApply] before evaluating <|"a"->1|> // Query["a"] and Dataset[<|"a"->1|>]["a"]. Only in the latter case will we see invocation of the type-inferencing system (TypeApply). And, of course, both you and I need only count bruises from attempts to use Dataset[...][...]. :) It has been my experience that non-dataset queries are reliable (and as far as I can recall every rare exception has been fixed).
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| Nov 16, 2016 at 19:08 | comment | added | alancalvitti |
is the type system and inference engine invoked in Query even when querying Associations (rather than Datasets)?
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| Nov 9, 2016 at 23:40 | comment | added | WReach |
Indeed. I tend to treat Dataset as a display wrapper much like MatrixForm, only adding it at the very end when it is time to visualize. I find the type deducer used for dataset creation to be much more reliable than the type inferencer used for dataset querying. On the other hand Query seems to be much more solid than it was in the early 10.x releases and I find myself using it quite a lot on general expressions (often displacing Map, Part, etc even for simple transformations).
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| Nov 9, 2016 at 21:12 | comment | added | alancalvitti | Thanks WReach, another detailed analysis. I think the type-system is a regression to C++/templates, is not that useful for its main intended application: formatting - in fact more often than not I Normalize it away and run ad-hoc formatting. | |
| Nov 9, 2016 at 21:08 | vote | accept | alancalvitti | ||
| Nov 4, 2016 at 3:16 | history | edited | WReach | CC BY-SA 3.0 |
added the section on work-arounds and showed the explicit signature in transpose responsible for the error
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| Nov 4, 2016 at 0:36 | history | edited | WReach | CC BY-SA 3.0 |
added 6 characters in body
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| Nov 4, 2016 at 0:31 | history | answered | WReach | CC BY-SA 3.0 |