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.

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4
votes
0answers
51 views

Convert .csv Dataset and store in Databin [on hold]

Trying out the new Databin product in the Wolfram Cloud. I have a simple ,-delimited .csv file with a header row which I have imported using the follwing: ...
9
votes
0answers
70 views

How does Dataset compare to DataFrame in pandas?

Pandas is a Python package providing fast, flexible, and expressive data structures designed to make working with “relational” or “labeled” data. Just like ...
17
votes
1answer
193 views

Visualizing Type System Operations

With the introduction of Dataset in version 10, Mathematica acquired a static type-checking subsystem. A fair number of dataset-related questions here on MSE ...
18
votes
2answers
232 views

Dataset seems to break Information

Bug present in version 10.2 My little function, from pre-10.2 ,to turn a headed table into a Dataset. ...
8
votes
2answers
66 views

Using Merge[Identity] and Transpose on a Dataset

While experimenting with this answer, I ran across the following: ...
9
votes
1answer
94 views

Odd StringTake problem in Dataset

10.2 Win64 Works fine... Dataset[{<|"a"->"ABC"|>}][All, StringTake[#a,{1,3}]&] Explicitly taking the whole string using its length directly. ...
7
votes
1answer
101 views

Converting a Table to a Dataset

I feel like this is a simple task, and there may be a built in method to doing this (but I can't find it if there is). I would like to be able to take a table and convert it into a structured Dataset. ...
5
votes
1answer
102 views

Streaming`LazyList`Testing may have a leak

Version 10.2; Win64 Enterprise. I'm seeing this message... data::shdw: Symbol data appears in multiple contexts {Streaming`LazyList`Testing`, Global`}; definitions in context ...
3
votes
1answer
52 views

Hold[Dataset[__]] not holding

With Hold[Dataset[Random[]]] instead of an expected Hold[Dataset[Random[]]] Can ...
16
votes
2answers
307 views

10.2 Dataset extraneous print using Transpose

Bug introduced in 10.2 and fixed in 10.2 (by paclet update GeneralUtilities 10.2.1) This is probably patch code in 10.2. Is there a way to turn off print with ...
22
votes
2answers
300 views

Dataset vs an association of associations

Associations with a record structure (e.g., a flat table) can be organised in one of two main ways. First as a list of associations, which is also used in the case of Mathematica's data set ...
0
votes
0answers
40 views

How to Export a mixture distribution to .json file

I would like to export the following mixture distribution mathematica found for my dataset to .json file ...
13
votes
2answers
227 views

Exporting Dataset to WDX format fails

I reported this to WRI support. Tracking number is CASE:3368636 Official answer is: Thank you for contacting Wolfram Technical Support. This is a known issue and our developers are working on a ...
4
votes
1answer
84 views

Query Dataset to check if row contains any from a set of values

For a given keyless dataset, I can query to return the rows whose columns contain a specific value. For example: ...
7
votes
4answers
244 views

How to iterate over the columns of a Dataset?

I have a Dataset with a simple structure, like this: ...
6
votes
2answers
190 views

Cutting away points that are not resonances

My situation is as follows. I have a whole bunch of data that I need to fit, which tends to look like this picture: As can be seen, there's three dips (resonances) and a whole bunch of noise around ...
5
votes
2answers
99 views

Dataset breaks multi-character StringSplit

Given ds = Dataset[{"a b", "c-d"} ] multi-character StringSplit is broken with Dataset ...
10
votes
2answers
128 views

Lookup with default broken in Dataset

Given an Association, ...
6
votes
2answers
180 views

Transpose can't handle fractions

Bug introduced in 10.0 and fixed in 10.2.0 Note: Dataset and Association are new in 10.0 Related to this question, why can't ...
4
votes
0answers
73 views

Why is Transpose Dataset slow in one direction

Transpose is faster when it distributes Keys at the 2nd level of a Dataset than when it factors them out. ...
4
votes
1answer
104 views

ANOVA test on dataset

I have a dataset with 3 groups and two variables. I want to do ANOVA test on the three groups for each variable. Does anyone know how to do this? ...
3
votes
0answers
51 views

Export to MX seems to corrupt the in-memory Dataset

I have a function that does a large number of calculations (by calling out to other smaller functions), and then builds a large Dataset object. Then I do two ...
11
votes
2answers
204 views

Simple way to concatenate Dataset columns

Consider these two datasets: d1 = Transpose@Dataset[<|"a" -> Range[5]|>]; d2 = Transpose@Dataset[<|"b" -> Range[5, 1, -1]|>]; {d1, d2} What's ...
1
vote
1answer
61 views

Plotting datasets using ErrorListPlot

I am trying to make list plots with the ErrorListPlot function. I have two datasets (ds1 and ds2) of which one plots nicely (ds1) and the other just give blank plots. I cannot see any difference in ...
2
votes
1answer
105 views

Applying a function to a column of a dataset [closed]

Functions can easily be applied to columns of datasets, as in the documentation it is shown. Now I want to apply a function with parameters to a column, but I get a list rules. E.g. ...
1
vote
1answer
46 views

Conditional Drop of a Key based on a test of the Value

I want to restructure a simple dataset. ...
3
votes
0answers
54 views

Applying functions to irregularly distributed Keys in Association lists

This Q is related to this one, but now refer to the situation as irregularly distributed Keys in lists of Associations: ...
2
votes
1answer
64 views

Applying Switch and Which to mixed-Key Association lists

Given an Association list w/ a common Key but also some distinct ones: ...
0
votes
1answer
81 views

A Query using Select and Quiet fails but Select by itself works

This is closely related to the question here, the key difference is that here data is structured as nested Association rather than a flat list: ...
0
votes
1answer
66 views

Dataset fails on StringMatchQ warning due to Missing value

Missing values are a pain mathematically and computationally in general not just in WL, but I think this problem is more related to Dataset handling of warnings: ...
0
votes
2answers
88 views

Is it possible to sum the results of a Map - Apply?

I am fairly new to functional programming and would like to replace a For[] loop that sums the results over a Dataset. This may be a bit different since the ...
1
vote
1answer
55 views
2
votes
1answer
51 views

Do Dataset functions get applied to rows in order?

If I have a dataset ds and perform an operation such as ds[All, f] does f get applied in the order the rows exist (the order they were placed into the dataset or as the result of a SortBy clause) or ...
1
vote
0answers
44 views

Multiplying two sets of data (x,y values, but different x density) followed by integration of the product

I've been trying to do this by myself today, but no luck yet. Please, see attached image. Basically, I do have two data sets A (x1,y1) and ...
12
votes
1answer
154 views

Dataset with more than 16 “columns”?

A Dataset with 16 columns or less is shown in a nice way: ...
7
votes
1answer
158 views

How would I use Map on a Dataset column?

I am somewhat new to functional programming. To improve the performance of a package, I would like to re-write a package in a functional style. I have the following ...
5
votes
2answers
105 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... ...
5
votes
2answers
194 views

Create a list of rules built from data set fields

I want to convert a dataset to a list of features and a list of target values, for use in Predict and also more generally. I know ...
17
votes
1answer
195 views

Why do lookup times in Dataset and Association differ by orders of magnitude?

Consider the following three data structures: a list of rules, an association, and a dataset: ...
0
votes
1answer
66 views

Need Query form to extract Min and Max DateList values for PlotRange from a Dataset

(* SUMMARY - In a Dataset holding DateList entries, how do I extract a minimum and maximum DateList value to pass into DateListPlot's PlotRange specification? See QUESTION further below *) (* Sample ...
4
votes
2answers
114 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? ...
10
votes
2answers
299 views

Why can I not replace a Dataset using a rule?

Simple replacement of a Dataset object does not seem to follow the expected behavior... Dataset[{}] /. _Dataset->1 Returns the empty Dataset not 1 as I would ...
2
votes
0answers
38 views

Encourage SemanticImport to assume numbers?

I would like to import a CSV without specifying the data type of each column before hand. SemanticImport almost does it, but doesn't appear to recognize numeric ...
2
votes
1answer
143 views

Dataset: sort rows in descending order of first column

I am new in the Mathematica community and I have a probably easy question for you regarding how to sort a dataset as the following so that I have sorted the values in the fist row descending from 44 ...
0
votes
1answer
112 views

Simultaneously fitting two data sets to two functions is too slow [closed]

I have to fit two data sets to two functions(eps1,eps2) with same parameters (w0,f,g) Initially, I know only one function ...
2
votes
2answers
164 views

Entropy of the elements of a general data set

I have the following data set, and wish to track the evolution of the entropy of each element within the set. I have evaluated the entropy for some elements, but how does one evaluate the entropy of ...
1
vote
0answers
57 views

What is the “Origin” rule for in a Dataset?

Take an innocuous Dataset. ...
6
votes
2answers
92 views

How does Grid operate on Dataset?

The documentation (10.0.2) indicates that Grid can be used to display a Dataset; the section in guide/ComputationWithStructuredDatasets labelled 'Dataset Presentation'. However simply invoking ...
1
vote
2answers
137 views

Delete rows from a dataset

I have a dataset built from a call to SemanticImport("/data.csv", Delimiters -> ",") with data.csv of the form: ...
0
votes
2answers
77 views

Select over many lists with changing selection criteria

I have many individual timeseries I am trying to align and compute the mean and other statistics for. The problem I am having is that I am only interested in aligning a particular part of each ...