Questions tagged [dataset]

Questions on the Dataset data type and related functionality introduced in version 10. Do not use for questions on data in more generic list format or data-manipulation questions generally.

Filter by
Sorted by
Tagged with
7
votes
1answer
1k views

Transform a table (list of associations) to a flat association

I would like to transform a table like ...
7
votes
1answer
381 views

Incorrect result while using SemanticImport for CSV file import

I might use this incorrectly. I want to use a .csv file that (as list) looks like: ...
7
votes
3answers
509 views

AssociationMap to query Dataset across levels?

Is there a way to operate on Dataset across levels to apply a function f to a key -> value pair in an Association as follows: ...
7
votes
1answer
116 views

Is there a way to get tooltip for parts of a string?

Is there a way to get the tooltip to appear for parts of a string? ...
7
votes
2answers
1k views

How do I plot multiple time series from a Dataset?

I have a Dataset ds with a straightforward tabular structure containing one column Date ...
7
votes
2answers
116 views

Creating a new Dataset column using a map from a second Dataset

Say I have two datasets: one is a detailed list of events, and one is a coarse list of events. I want to add a column to the detailed list from the coarse list (for the purposes of sorting). For ...
7
votes
2answers
166 views

Associations of List is not printing properly in mathematica 11

<|"i1" -> {a11, a12, a13}, "i2" -> {a21, a22, a23}, "i3" -> {a31, a32, a33}|>//Dataset The above code produces the following where rows are still ...
7
votes
3answers
381 views

Enabling JoinAcross to merge non-joined keys

I've come across the following "JoinAcrossMerge" sufficiently often to wonder if Dataset's semantics can offer a natural implementation. Say I have 2 datasets (<...
7
votes
1answer
152 views

Why does an inert ReplaceAll modify this Dataset?

I cannot see any reason for this behavior besides a bug, but I've been wrong before so I put it before the community: ...
7
votes
1answer
134 views

SemanticImport and zip files

I have looked through the documentation and don't see this addressed, but since some of you seem to have knowledge of undocumented features, I thought I'd ask. There is a zip file at http://www....
7
votes
1answer
137 views

KeyTake, KeyDrop fail with Transpose in Dataset

I think similar to unexpected-behavior-of-keytake there are other issues with v11.0 KeyTake and (more useful) KeyDrop that show ...
7
votes
1answer
283 views

Possible bug involving Dataset/Query and RightComposition

Bug introduced in 10.0.0 and fixed in 10.0.1 Short Version Why are the results of the following expressions different? ...
7
votes
1answer
214 views

JoinAcross Crashes Kernel in Version 11.0

Bug introduced in 11.0.0 and fixed in 11.0.1 The following executes without issue in 10.4.1 and returns immediately. However in 11.0 when the JoinAcross line is ...
7
votes
1answer
203 views

Writing code which generates a function to append many columns to a dataset

I love datasets in Mathematica. Say I have one that looks like this: ...
7
votes
3answers
433 views

Appending and Prepending columns to a dataset in 10.0.2.0

fixed in 10.1 (windows) I just experience a problem in prepending columns to a dataset. I did this a hundred times in 10.0.1.0 - no problems. Now it seems as if it is only possible to append/prepend ...
7
votes
0answers
70 views

Dataset Crashes Information and Definition functions

Bug in 11.0.1 fixed in 11.1.0 Has anyone else noticed this odd function crash with Datasets. Try the following in a clean kernel. ...
7
votes
0answers
83 views

How to navigate a large Dataset with keyboard short-cuts?

Update : Starting in 11.1 the navigation buttons are fixed to the left-hand side instead of being centered and don't jump around anymore. Starting with version 11.0 ...
6
votes
3answers
755 views

How to create a table?

I have looked here at the forum and on the mathematica documentation center though still couldn't get it to work. I have two lists ...
6
votes
4answers
406 views

Average dataset with many repetitions?

I have a dataset where each item is of the form: <|"p1" -> x1, "p2" -> x2, "r1" -> y1, "r2" -> y2|> The interpretation is this: ...
6
votes
2answers
896 views

Good way to create a similarity / distance matrix for a large dataset [duplicate]

I have a large dataset with rows (100k+) for products and columns for features. Now I want to create a similarity matrix with NormalizedSquaredEuclideanDistance. ...
6
votes
3answers
153 views

How to convert a Dataset into an indexed dataset / association-of-associations given a column header?

Given a dataset as such If "letter" is the header that is chosen, how do I convert it into an indexed dataset / association-of-associations? i.e. How do ...
6
votes
2answers
214 views

DeleteMissing level spec confusion

Given: titanic = ExampleData[{"Dataset", "Titanic"}] Why does this correctly delete Missing[] elements: ...
6
votes
4answers
275 views

GroupBy dataset values and length

I have a dataset, and I want to group by one of my columns, and then show the Length of another set of columns for each group. For example: ...
6
votes
3answers
1k views

How to SemanticImport Multiple Excel Sheets

I have an Excel workbook with multiple sheets that I'd like to import into a dataset each. With Import I can target individual sheets by their name into a nested ...
6
votes
2answers
692 views

Convert a huge txt-file into a dataset

My friend has this huge txt-log of sea levels. He wants to organize it into a dataset. After importing it this file a used StringSplit to separate it into rows, then to singular elements ...
6
votes
1answer
292 views

How to filter this nested list of Association

For example, I have the following data ...
6
votes
1answer
403 views

MapAt and generic Functions on Associations and Datasets

These are distinct but related questions about mapping functions to Associations and Datasets. Given: assoc = <| a -> 1, b -> 2, c -> 3|> And <...
6
votes
2answers
172 views

Dataset and Select with a SmoothKernelDistribution

This question is hopefully a case of stupidity on my side, but I just don't understand why this happens. I had code that worked perfectly fine for several weeks and gives an error now on Linux and Mac....
6
votes
2answers
431 views

Using Dataset with TimeObjects in EventSeries

I'm new to Mathematica, and while this is potentially quite easy, I'm having difficulty using TimeObjects in the EventSeries ...
6
votes
2answers
166 views

Dataset Query using Composition fails but RightComposition works - why?

V10.1 on Win764 Enterprise. In this (CORRECTED) example the two Queries may be compounded into one using RightComposition sucessfully... ...
6
votes
2answers
303 views

Apply an accumulative function to each column of a dataset

Given a dataset with many columns, how can apply a function (in this case Count[Missing_]) to each column? ...
6
votes
2answers
183 views

How to speed up Min of DateObjects?

I'm in version 10.0.1 using a Dataset to do some plots and things. For one of the plots I need to get the minimum date of a some filtered set of the ...
6
votes
1answer
153 views

MaximalBy[#, “votes”] & not equal to MaximalBy[“votes”]?

I'm looking at the results of the 2015 UK general election ...
6
votes
2answers
596 views

How can I save a Manipulate's control settings to a dataset?

This is probably an extremely simple question. I have a manipulate that sets variables used to define an offset, amplitude, frequency and phase of a trigonometric function. ...
6
votes
2answers
696 views

Why this syntax for renaming columns in datasets?

Form the documentation of Dataset: ...
6
votes
1answer
91 views

Dataset: Failure when using functions that generate messages

Consider the dataset: data = Dataset[{<|"A" -> 1|>, <| "A" -> 2|>}] Define the function: ...
6
votes
1answer
124 views

Hold[Dataset[__]] not holding

Bug introduced in 10.0 and fixed in 11.0.0 With Hold[Dataset[Random[]]] instead of an expected Hold[Dataset[Random[]]] ...
6
votes
2answers
134 views

Add a column to the left side of a dataset

What I am trying to do is to add an id column at the left side of my data set. This is the data set I am working with. I Have three columns and I want to add a new column on the left side with the ...
6
votes
1answer
236 views

Only String Keys supported in Dataset's Association Query?

fixed in 10.0.2 Given data: titanic = ExampleData[{"Dataset", "Titanic"}] This Association Query works: ...
6
votes
2answers
162 views

How to subtract two lists based on a key

Let's say you have the following datasets {set1, set2}: ...
6
votes
1answer
132 views

How to update values of particular keys efficiently

Say I have a list of Association, SeedRandom[45] test = Association[Table[i -> RandomInteger[30], {i, 6}]] <|1 -> 18, ...
6
votes
4answers
813 views

Selecting data from multiple columns

Mathematica has almost the following example in the documentation: ...
6
votes
1answer
368 views

Applying different functions to Dataset columns after GroupBy

I have a list of associations dataset. ...
6
votes
2answers
143 views

JoinAcross question with combined keys

I would like to join associations in the following way. Say I have a dataset d1: ...
6
votes
1answer
122 views

Built-in (or Terse) Method to Combine and Transpose Datasets

From some calculations I have ended with Datasets of the form: ...
6
votes
1answer
121 views

Idiomatic way to turn GroupBy field back into a column when aggregating

I'm trying to find a way to convert a GroupBy field in a dataset into a column after aggregation, but I'm clearly failing to this idiomatically, although I found a ...
6
votes
1answer
276 views

Select query with named slot lookups?

Given this Dataset fragment (copy-paste friendly version at bottom) Can this query be simplified by referencing named slots directly in the ...
6
votes
1answer
800 views

Multicolumn sorting with ordering functions and precedence

I am aware that the question of "how do I sort on a column" has been asked in various forms, most notably this one. While some powerful solutions have been presented, as far as I can find no one ...
6
votes
1answer
174 views

How can Map be given access to the keys of a Dataset?

Consider an example Dataset: ...
6
votes
1answer
153 views

General question about data management

I am curating a small number of databases-actually I am not sure if they qualify as such; they are more like collections of-loosely-related data points; the problem is that they are growing over time; ...

1 2 3
4
5
12