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.

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5
votes
1answer
800 views

How can I modify specific key values within a dataset?

Given a dataset, is there a way to modify a value? Example ...
5
votes
1answer
422 views

Trouble with Datasets in Version 10.0.1

Almost every morning, when I start my work, I observe the same problem as already mentioned here: Using Datasets in Mathematica 10.0 and here: Dataset: cannot reproduce a basic example. A bug? I ...
5
votes
1answer
182 views

Dataset: best practices for unordered hierarchical data

Note: the editor warns that this is a "subjective" post, but I am looking for an objective answer (e.g. in relation to easy of use of the many built-in functions, speed, etc). Suppose you have a ...
5
votes
1answer
169 views

How to judge if two Dataset are equal

I don's sure this is a bug or not.Suppose I have a dataset ...
5
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0answers
40 views

Why this shadowing when dealing with a dataset? [duplicate]

I have a dataset which I use as "dsall" and a function keylist (just for my convenience, nothing spectacular): ...
5
votes
0answers
253 views

Convert .csv Dataset and store in Databin [closed]

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: ...
5
votes
0answers
266 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
4answers
202 views

Padding a column of lists

I have data in the the form of a table, whose one column is the following ...
4
votes
3answers
148 views

Problem with NonLinearModelFit for Sine behaviour

I'm trying to fit this following set of data: ...
4
votes
2answers
215 views

Blocking Dataset`$ElisionThreshold doesn't work

I would like to define a simple function to automatically show all rows in a Dataset. Based on Taliesin Beynon's answer, I tried the following trivial snippet: <...
4
votes
3answers
404 views

Apply a function to each row of a Dataset

Have a Dataset which is derived from the output from another program. Have written some functions to retrieve and format this data. Can make this work as intended ...
4
votes
1answer
187 views

How to Extract (Magnetic) XYZ Data Points from Color (Airborne Magnetic Survey) Image and Legend

I've been trying to work my way through this by working through search results like: Data extraction from a picture of a graph Numeric data from a color map Extract bathymetry data from a map I can't ...
4
votes
2answers
411 views

convert from a dataset to list

I have a Dataset of only 1 column to start with, and I want to StringJoin every element there. Got the error message ...
4
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2answers
114 views

How to pull out the underlying query syntax being used by dataset?

Consider the following dataset. titanic = ExampleData[{"Dataset", "Titanic"}] If I use the lookup syntax of the dataset like following it creates an equivalent <...
4
votes
2answers
254 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 ...
4
votes
1answer
147 views

Plot mean of data with error bar

Suppose I have the following data with co-ordinates: {{1,190},{1,200},{1,210},{1,180},{1.5,175},{1.5,200},{1.5,190},{2,100},{2,150}} How do I make a listplot of this data set, by taking the mean of ...
4
votes
2answers
130 views

Problem with nested mapping for Dataset structures

Consider the following dataset: ...
4
votes
3answers
235 views

Chart a PairedHistogram from two columns of a Dataset

I'm currently experimenting using the Titanic example data set: titanic = ExampleData[{"Dataset", "Titanic"}] I'm able to extract a specific column and then ...
4
votes
2answers
599 views

With “named row” nested Datasets: How to Select or Filter rows by row key with criteria from another Dataset?

After some calculations and grouping I have a Dataset similar to the following form: ...
4
votes
2answers
419 views

Merge two database with a common key

I have two list: in one of them the name of certain compounds, and in the other one the properties of each compounds. So I want to merge them to have for each compound name the relative properties. ...
4
votes
2answers
235 views

Use Select to filter a dataset's sublists

In the following Dataset, I want to use Select to display only rows, which contain numbers in column ...
4
votes
2answers
184 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 ...
4
votes
1answer
72 views

Create a new list from given data

Let us consider the following type of data list ...
4
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2answers
112 views

Select dataset rows that meet a mathematical criterion in a column

Here is a simple dataset: ...
4
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2answers
93 views

Is there a way to `Merge` with different functions across Keys?

Many times when working with Dataset I have to GroupBy. If for example, I group by and aggregate on columns of the same type ...
4
votes
1answer
474 views

Replace Elements in a Dataset by rules

I've got a dataset with 100+ various columns. I want to change e.g. the values 0 and 1 in the first column with "male" and "female". In the second column i'd like to change the 0 and 1 with e.g. "...
4
votes
1answer
65 views

A simple way to extract information from this dataset with Query?

I have a dataset comparable to the following (you may wrap it in Dataset if you like). I am looking for a relatively simple way to query it and extract information. ...
4
votes
1answer
172 views

Combine datasets with partially different columns row-wise

I have a problem, which I assume to be trivial, but can't solve it: I have two datasets, ...
4
votes
1answer
170 views

Passing values from a list to Select during a Dataset query

Given a Dataset: ...
4
votes
1answer
166 views

Openning JSON file, (NDJSON, new line delimited) — big file

I am trying since many hours to open a JSON file ("new line delimited") that has this as structure ...
4
votes
1answer
132 views

DeleteMissing doesn't match in Association tables

DeleteMissing doesn't work in Association tables: ...
4
votes
1answer
1k 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. ...
4
votes
2answers
233 views

Using GatherBy with a DataSet's header designation instead of First

Using the code, where ds is data formatted into a Dataset GroupBy[ds, First] // TableForm I get a table that I wanted, but I was wondering if I could somehow use ...
4
votes
1answer
2k views

How would I obtain a list of column names in a Dataset?

I really love the addition of Dataset to Mathematica. I would like to write a basic utility function that exports a Dataset to Excel. Is there a way to get a list of column names from a Dataset?
4
votes
1answer
58 views

Custom object display in Dataset using MakeBoxes

The below code defines a couple "objects" in the Mathematica sense using a convention consisting of so-called Q-functions for creating types and data validation, ...
4
votes
1answer
78 views

Inconsistency in getting Keys, Values and Query for nested Rules

Querying nested Rule expressions of the form a -> v -> b // FullForm Rule[a,Rule[v,b]] for ...
4
votes
2answers
83 views

Simple dataset query

Why does taking a Part fail in a Dataset query function when there is an operation in the index argument? ...
4
votes
1answer
67 views

How do I import a Dataset that contains lists?

The very first example in the Dataset documentation is the following: ...
4
votes
1answer
1k views

How to filter a dataset using Select and a parameter

I'd like to filter a Dataset using a parameter in Select, but so far I haven't been able to make it work properly. Say that I ...
4
votes
2answers
92 views

Using subquery in Query of Dataset

I want to create a Query to a Dataset that will select a subset of three columns, modify the date column in this subset (to month), group by month and a second column (location), take the group means ...
4
votes
1answer
80 views

Operator form for Histogram of multiple datasets?

I would like to plot a histogram for multiple datasets in a dataset query, but can't quite seem to make it work in operator notation: ...
4
votes
1answer
92 views

Replacing “Unmatched” with value

I have two datasets ...
4
votes
1answer
377 views

How to Operate on a Dynamic Dataset?

I cannot operate on the Dataset I am dynamically filtering. Minimal example follows. ...
4
votes
1answer
141 views

Upvalues for Missing do not work with Dataset

Consider the following Dataset: d = Dataset[<| 1 -> Missing[], 2 -> 1.0, 3 -> 4.0 |>] And the following Upvalue for Missing: ...
4
votes
1answer
197 views

Extraction of rows with even numbers of a dataset

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4
votes
2answers
385 views

GroupBy and MaximalBy to create a new Dataset

I'm looking for a neater way to achieve this, which to me looks awkward and suggests that I am missing something... Given a Dataset... ...
4
votes
3answers
328 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. ...
4
votes
1answer
218 views

Why is there a lot of noise in the Wolfram Blockchain?

I tried to look into the transaction history of the Wolfram Blockchain. I tried this:- ...
4
votes
1answer
92 views

How to find the block number of a transaction in a Wolfram Blockchain?

For example, in block 1004 of the Wolfram Blockchain, I can get the 4th transaction's ID by using the following code:- ...
4
votes
1answer
79 views

How to display a True/False table [closed]

Below is my written program ...

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