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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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2answers
137 views

Exporting dataset with NumberForm

I have a dataset which includes strings and numbers. I want to export it in CSV with all numbers being printed with 2 decimals. I tried several functions like mydataset=NumberForm[#, {Infinity, 2}...
9
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1answer
191 views

Dataset - append row with a value which depends on two other rows

I have go through the forum but did not see this question. Hope I don't miss it. I want to add a new colum "C" to a dataset with existing columns named "A" and "B". The value of "C" shall be the ...
1
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1answer
90 views

Neat way to make Dataset from RecurrenceTable

I just learned that I can create a Dataset by combining Dataset and Table functions. For example: ...
4
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1answer
140 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, ...
7
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1answer
308 views

Export of (large) Dataset lasts very long

I have a Dataset (non numerical data) which has a ByteCount of about 14GB, When I export it to disc (SSD) the resulting ".m" or "...
0
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2answers
302 views

How can I turn the first column in a dataset into row names?

I've used SemanticImport to import to a "TSV" spreadsheet into a Dataset. Each row starts ...
2
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1answer
100 views

Problem understanding Datasets with keys that are not strings

I am having difficulty understanding the difference between Dataset with strings as keys versus using symbols as keys. Below is a very simple toy dataset (my ...
8
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1answer
131 views

Adding metadata to non-atomic expressions in Associations and Dataset

Information and Attributes require arguments to be symbols and strings , whether built in or user-defined. there's often the ...
0
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0answers
86 views

Datelistplot and datasets. Plotting several time series with mapping functions and adding options

Following the post How do I plot multiple time series from a Dataset?, I have additional questions. I have a dataset with four columns. First is the date. 2nd to 4th are values (v1,v2 and v3). ...
4
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2answers
651 views

Change value in a Dataset

I could not find an answer on this fundamental question, even though I was reading the references on Dataset and Association and ...
0
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2answers
124 views

How to deal with dataset with missing items?

I collect some data with missing items. data = Dataset[{<|"a" -> 1, "b" -> 2|>, <|"a" -> 11|>}]; It's not right to do ...
0
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1answer
38 views

Is there a way to use CellPrint on dataset objects?

I am trying to assign a cell tag onto my cell with contents in the form of a dataset. However, I am receiving the following error: The wrong number of arguments (12) was given to a box ("BoxData") ...
9
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1answer
111 views

Export[…, “tsv”] drops minus signs from Dataset [horrific bug?]

Toy example: First, create a Dataset: ...
3
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1answer
117 views

Query from Association of Associations Dataset

I have a rather large dataset comprised of Association of Associations. For better or worse, I've converted this into a Dataset. Here is a simplified version of ...
0
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1answer
220 views

Correct format to import vector from file

Although this question was kind of already asked, it was closed because not enough information was given. Here is my attempt. I am trying to find out the correct format to import a vector data set (...
1
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1answer
67 views

Syntax for transforming column in a dataset [closed]

Suppose I have a dataset a, featuring a column labeled n, whose values are all string representations of integer values. I want ...
5
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2answers
674 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 ...
3
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2answers
85 views

Creating dataset from list of ragged associations with defaults for missing keys

Given the ragged dataset in form of association of associations: ...
1
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0answers
59 views

Dataset inactive when shown from button action

Bug introduced in 11.1.1 (or earlier) and persisting through 11.3 CASE:3919858 This dataset is active: ...
4
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3answers
407 views

Select dataset columns after GroupBy

Very basic question. Probably showing my ignorance, but if I have a dataset like the example in the docs ...
0
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1answer
77 views

Dataset with the same triples as both row and column headers

I have a list of triples and a matrix. I want to use the triples as header for row and column in a dataset so that it looks like this: But with the code I have so far it makes the wrong associations: ...
0
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2answers
284 views

Dataset, use list as header

I have a dataset with a header for row and column which consists of binaries, e.g.: ...
5
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1answer
153 views

How to judge if two Dataset are equal

I don's sure this is a bug or not.Suppose I have a dataset ...
3
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1answer
115 views

Simple dataset query fails

This is really weird. I can get the first row and a specific column from my Dataset, but when I try to get them both, I receive a cryptic error. What in the world could it be talking about. myData ...
4
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1answer
247 views

Applying different functions to Dataset columns after GroupBy

I have a list of associations dataset. ...
2
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1answer
121 views

How to format the output of GroupBy in a Dataset

Suppose I have a dataset titanic = Uncompress[FromCharacterCode[ Flatten[ImageData[Import["http://i.stack.imgur.com/sd05e.png"],"Byte"]]]] This two ...
4
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1answer
131 views

Unstable Dataset Formatting [duplicate]

I have a list of associations data set. If I do a simple Mean[] with GroupBy on two columns, I get a nice tidy table display. <...
5
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1answer
173 views

Sum some columns in list of associations grouped by other columns

I often need to sum values in a list of Associations according to some columns in that Association. I have a way of doing it, ...
0
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1answer
125 views

Making an interpolation function from data imported with SemanticImport

I imported a list of data using k = SemanticImport["Desktop/k_CARBON_eV.txt"] And then I wanted to interpolate the data using: ...
3
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3answers
195 views

RDataFrame to Dataset

Is there an easy way to convert an RDataFrame object to a Mathematica Dataset? For example I have an R function which returns ...
0
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1answer
58 views

How to create a ListStreamPlot using two imported images

I have two .mat files containing xdata and ydata (each having dimensions {27,256,256}. These are kind of stacks of 256x256 images. I want to create a ListStreamPlot using a specific slice of the image ...
8
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3answers
182 views

Sum all columns from a list

I have a list of column names: list = {"col1", "col2", "col3"} and a dataset ds. I want to add a new column to ...
6
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2answers
127 views

JoinAcross question with combined keys

I would like to join associations in the following way. Say I have a dataset d1: ...
3
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1answer
117 views

Single argument operator form?

I've heard the explanation that functions like StringDrop[] are varargs and so that is why they do not have an operator form. But when you are only using the ...
14
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2answers
711 views

How to work with a Dataset?

I have an application for which a Dataset appears useful. I want a structured dataset which consists of a set of records, which are presumably Associations. For the data set, I would like to be able ...
1
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2answers
129 views

how to work with dataset without column names

I have a dataset of 2 columns as follows a 1 b 2 c 3 That dataset doesn't have names for both columns, how should I use select to work on it, i.e., get data with the second column number ...
4
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2answers
273 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 ...
0
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0answers
58 views

Exporing Dataset to CDF hangs (Mathematica 11.0.0 Linux 64 bit)

I want to export a TabView to a CDF. Some of its tabs have Dataset. ...
2
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1answer
288 views

3D plot to 2D plot

I think someone should have asked this, but I could not find the answer. If anyone knows similar question, please let me know on the comment! I want to convert 3D data to 2D cross section data. For ...
6
votes
1answer
148 views

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

I'm looking at the results of the 2015 UK general election ...
7
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5answers
340 views

Group by multiple keys, merge at specific keys in dataset

I want to join associations in a dataset which share identical keys specified by the list sameAt and merge them by taking a Mean ...
16
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2answers
321 views

Dataset shows an “All” Key when it contains a List of Associations

From a process I have a Dataset similar to this minimal example. ...
3
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1answer
70 views

Elegant way to return first non-Missing column in Dataset

I have a Dataset[] with some data and a TON of columns. Each row contains several columns for dates, which contain DateObject ...
8
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1answer
336 views

Transpose fail in 11.1 Dataset

The type system underlying Dataset seems a total kludge, as soon as one issue is fixed, here it recurs in a slightly different form - and difficult to isolate in minimal examples. Here's a failure ...
3
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1answer
75 views

Dataset type system fail with composite keys and Infinity

In 11.1, a Dataset consisting of an Association with composite keys with an Infinity causes failure in keying-in: ...
13
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2answers
238 views

Is there a way to exert finer control Dataset Cell Coloration Like in Grid?

In Grid one can control the foreground and background color of specific cells, rows, and columns, whether initially or via computation. Although Dataset seems to use Grid intrinsically, from existing ...
7
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1answer
128 views

Can Mathematica Neural Net make use of the REC file format for images like MXNet?

When using large set of images for training neural networks (>10000, size 250 x 250 each) the time to read the images is quite long. My first approach was to use the DataSet functionality of ...
8
votes
1answer
180 views

Why are empty lists not consistently formatted in a Dataset?

A support case with the identification [CASE:3876977] was created. I just noted, that an empty list is not consistently formatted in a Dataset: ...
1
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0answers
28 views

DateString doesn't evaluate within Dataset [duplicate]

[11.1] Starting with a DateObject in a Dataset: data = Dataset[<|"a" -> Now|>] ...
4
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2answers
283 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. ...