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1
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2answers
55 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 ...
3
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0answers
38 views

The case for “Across” generalizing JoinAcross

EDIT: Initially, I called this function "KeyOuter", but "Across" is more appropriate given the connection to JoinAcross. Given: ...
4
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0answers
210 views

Dataset in Mathematica 10.0.1

Wolfram pages "Mathematica Quick Revision History" in Mathematica 10.0.1 release says: "New operators and compositions of operators enabled for associations functions such as Dataset and Query" ...
8
votes
5answers
120 views

Applying a function to a Dataset column conditional on another slot's value

How to apply a function to a column conditional on another slot's value? The Dataset documentation show only how to apply a function to named slots independently. The ...
1
vote
1answer
45 views

Select data from a Dataset [on hold]

I have a dataset that looks like ...
6
votes
2answers
75 views

DeleteMissing level spec confusion

Given: titanic = ExampleData[{"Dataset", "Titanic"}] Why does this correctly delete Missing[] elements: ...
1
vote
1answer
44 views

ReadList or any other command to read in blocks of very large numbers

I have a data file, data.txt, having following data: ...
8
votes
2answers
94 views

Missing: KeyGroupBy?

Especially in tree-structured data, keys and values, being two sides of the same coin, frequently interchange roles. The ability to aggregate by value but not by key upsets the balance. How to ...
6
votes
1answer
60 views

Only String Keys supported in Dataset's Association Query?

Given data: titanic = ExampleData[{"Dataset", "Titanic"}] This Association Query works: ...
2
votes
2answers
77 views

How to make functions from datasets

I have a csv that encodes the results of plugging certain parameters (say, A and B) into certain functions (say, ...
3
votes
1answer
107 views

Import iTunes xml data and convert it into a dataset or table

I have an xml file with song data from iTunes (https://dl.dropboxusercontent.com/u/1012958/iTunes%20Library.xml) and I'd like to import it to Mathematica to do some statistics. I get an XMLObject like ...
5
votes
2answers
105 views

Advanced SQL-type select statements (filtering) on Datasets

I'm trying to improve on mathematica's handling of datasets. I'm currently writing this function that should do the following. Suppose I have a dataset with columns, e.g. ...
7
votes
2answers
83 views

Problem constructing Association tables with some operators

First, set up the example Dataset from the documentation: titanic = ExampleData[{"Dataset", "Titanic"}]; Why does this fail: ...
7
votes
1answer
105 views

Group dataset on two keys (GroupBy)

I would like to group the elements of row c of the following dataset according to the values in the columns a and b. That is Go from here To here And then I would like to print this on a grid, ...
5
votes
2answers
95 views

Change dataset key name

Using the example in the documentation, how would I make a new dataset with the key "b" changed to key "h". ...
5
votes
2answers
114 views

How to lookup by a string key after GroupBy? Inconsistent data type handling

This is relates to a bug that was introduced in 10.0.0 and fixed in 10.0.1 It also relates to an issue that has yet to be corrected. After applying GroupBy to ...
8
votes
1answer
90 views

Possible Bug in ProbitModelFit when used in a Dataset

Since upgrading to Mathematica 10 on Mac OSX I have come across a number of instances of this error, which occurs using Probit and Logit model fit. A bit of googling show this is something to do ...
3
votes
2answers
89 views

Simplifying a time-series segmentation Query

This query segments a time-series and filters out dropout frames. Can it be simplified - ie, made more readable? ...
9
votes
2answers
115 views

Does Dataset round? [duplicate]

I'm importing the following Excel file: My code and its results are: ...
12
votes
1answer
167 views

Export dataset to JSON

I'm experiencing a weird issue. Consider a dataset defined like this: dataset = Dataset[{<|"a" -> 1, "b" -> 2|>, <|"a" -> 3, "b" -> 4|>}]; ...
7
votes
0answers
123 views

Median of Dataset in Mathematica 10

I'm having trouble calculating the median of a Dataset[] in Mathematica 10. The situation is as follows. Consider a dataset that was defined as follows: ...
5
votes
1answer
168 views

How to split a Dataset into training and testing for machine learning?

Suppose I have iris data In the Dataset Format. How to split the iris data Into training and testing for Machine learning? For example,Transform the data for Classify.
10
votes
3answers
206 views

GroupBy several keys while keeping the Dataset as a Table (List of Associations)

Assume you import data from a Table source of the following format. ...
10
votes
4answers
209 views

Dataset: get number of levels and elements

The summary box for Dataset objects shows the number of levels and elements at the bottom. How can we get these values programmatically? For example, "4 levels, ...
4
votes
2answers
88 views

Create composite key - operating across rows in a dataset

I would like to be able to create a new dataset by extracting 2 columns to make a composite key, and also extracting other columns. For example, suppose my dataset looked like: I would like to ...
7
votes
4answers
209 views

Join two datasets on keys

I want to be able to join two datasets by keys, pretty much like I'd do in SQL. I thought the JoinAcross function might do it, but it doesn't operate the way I thought. The example in the ...
5
votes
3answers
197 views

Display ALL keys in dataset

I created a dateset (estimates) with 25 keys (my columns), and about a hundred rows. I'd like to be able to list the keys from the dataset. I did this: ...
7
votes
2answers
134 views

Export a simple DataSet with key-value associations to CSV in Mathematica 10

I'm trying to Export a simple dataset with key-value pairs to a CSV Export["n.csv", MyDataset, "CSV"] This results in a single-line serialization: ...
10
votes
1answer
118 views

Using MapIndexed[List] on a dataset fails — why?

The following works: MapIndexed[List]@{1, 2, 3} (* {{1, {1}}, {2, {2}}, {3, {3}}} *) This works too: ...
7
votes
0answers
99 views

How to merge Datasets representing matrices with named rows/columns?

I am working with square (non-symmetric) matrices with named rows and columns. The data I receive is sometimes messy and rows/columns may come in various permutations. I usually need to ...
8
votes
1answer
232 views

Why is Dataset upset by division by zero?

Consider this example: ds = Dataset@Transpose[<|"a" -> {1, 2, 3, 4, 3, 2, 1}, "b" -> {6, 5, 4, 3, 2, 1, 0}|>, AllowedHeads -> All] Now say I ...
8
votes
2answers
194 views

Unexpected behavior when using SortBy as a dataset filter

I am still experimenting with datasets. Recently I tried to query the Titanic example to get info on the oldest passengers. Here is what I tried ...
5
votes
2answers
100 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. ...
0
votes
0answers
61 views

How to modify a Dataset? [duplicate]

How does one go about modifying parts of a Dataset? Could the answer please solve the following as an example. Start with the ...
8
votes
1answer
89 views

Operator syntax for Merge-like Query

Is it possible to take advantage of Dataset's Query operator syntax to Merge parallel queries thereby avoiding Function's that are otherwise required? Using the planets data: ...
7
votes
1answer
116 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? ...
0
votes
0answers
39 views

Cannot convert list of associations to dataset for length longer then 4 [duplicate]

Situation: I initialize two ranges: range1 = CharacterRange["a", "d"] range2 = CharacterRange["a", "i"] Create associations: ...
8
votes
0answers
105 views

Benefit of using Dataset to collect SQLSelect output

Considering a DatabaseExample included with Mathematica: ...
25
votes
4answers
525 views

What is the natural way of using Dataset to get a FittedModel?

The new Dataset in Mathematica 10 is a great addition to the language, potentially reducing the convenience gap with R. Given this, I would like to understand what the equivalent simple or natural ...
7
votes
2answers
117 views

How to insert zero counts uniformly with Dataset Counts query

Missing[] is generated when an association does not contain the specified key. ...
1
vote
1answer
50 views

How can I append associations with uneven elements? [duplicate]

My dataset is pretty simple so far: ...
6
votes
0answers
180 views

Learning Resources for Data Science in the Wolfram Language

I'm delivering an upcoming course on Data Science with the programming/analysis done predominantly in the Wolfram Language. I created the following table to leverage students' familiarity with Lists ...
7
votes
1answer
104 views

One ChartLegend for multiple charts in Dataset?

Dataset's documentation shows how to leverage GroupBy operator at multiple levels ...
7
votes
3answers
226 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: ...
11
votes
2answers
205 views

Can't get Append to append a record (association) to a dataset

The Documentation Center item, Computation with Structured Datasets, implies that Append has been extended in V10 to work with datasets. But not on my computer. (I ...
7
votes
3answers
232 views

Converting datasets to nested lists

Imagine the Shipments relation: ...
3
votes
3answers
152 views

How to generate and label multiple histograms as Query operator(s)?

The Dataset documentation doesn't indicate how to label a Histogram with the key. ...
5
votes
1answer
208 views

What are the Slot Names in a Dataset?

I have a dataset which are keyed on {"Item", "Hour of Day", "Value"}. In the examples, I noticed that it is possible to apply functions using such as ...
9
votes
1answer
207 views

Converting structured data to a dataset

A Dataset seems perfect to represent structured data. Has anyone already thought about how to convert as efficiently/elegantly as possible an XML or JSON file to a Dataset in Mathematica 10 ?
2
votes
0answers
231 views

Dataset Mathematica 10.0

I started to use the new funcationality 'Dataset'in Mathematica 10.0. ...