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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3
votes
1answer
59 views

Add columns with dummies and specific headers to dataset

I got a dataset that looks like the following example: ...
2
votes
2answers
71 views

Group Datasets and take minimum/maximum

Good Morning I have the following dataset: And I try to reach this output: key: only one row per key text: join all texts of the rows with the same key (but no duplicates) min: take the lowest ...
0
votes
0answers
21 views
1
vote
2answers
45 views
0
votes
0answers
18 views

DO Button: convert databin entry from String to Reals

I am learning to use the Wolfram databins and DO Button and DO Note apps for a personal project. The sample code I am using as the Recipe is: ...
2
votes
1answer
110 views

Classifying images in mass with URLs and CSV file

I'm looking to train a image classifier with a large number of examples and categories (30,000 & 100). I would then import a file of image URLs that need to be classified, and export the results. ...
5
votes
2answers
309 views

How to construct a dataset with lists as columns

So I know this should be pretty easy, but I cannot seem to find a solution anywhere, so thanks in advance for your help: I have three Lists (with numbers as ...
4
votes
2answers
129 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 ...
3
votes
1answer
136 views
1
vote
0answers
32 views

MedianDeviation upsets Dataset in 10.3.1

This seemingly innocent piece of code seems to choke the interpreter somewhere... ...
0
votes
0answers
34 views

Changing default display behaviour for Dataset

I have a function (whose code is in this site) to display Dataset in a more convenient way. To the extent that I never use the default one. I find myself constantly ...
2
votes
1answer
70 views

Help with Time-Seried dataset

I can't seem to figure out the best way for directly inputting interpolated values into a dataset. I turn to your expertise for guidance. So, I have a multi-year time-series dataset. Column 1 is time ...
11
votes
1answer
188 views

Getting data from FRED

Mathematica V10.4 supports a service for connection to FRED. If you create a connection with fred = ServiceConnect["FederalReserveEconomicData"] (you need to ...
1
vote
0answers
44 views

Save experimental data within notebook. Is it possible? [duplicate]

I'm trying to use Mathematica for all my scientific needs as much as I can, so I can learn. When I want to plot my experimental data using Mathematica, I've been Import[] and plot data sets. However, ...
6
votes
3answers
151 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 ...
6
votes
4answers
260 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: ...
4
votes
0answers
90 views

How can I add column-rearrangement-by-mouse-dragging to my dataset display function?

A subject that I seem to take at heart... I was expecting an upgrade of the default Dataset display in MMA 10.3.1. It did not happen. Among the features I would have liked to see improved is a ...
17
votes
0answers
128 views

V10's TypeSystem - what are these function useful for? [closed]

The symbols in the TypeSystem` context are clearly used for working with Datasets, but they seem powerful. I was hoping that someone could help explain how they work and is they are useful for ...
3
votes
0answers
67 views

Map level inconsistencies with Missing values [closed]

Negative Level specs interact with Missing values, eg: ...
9
votes
2answers
114 views

A subtlety in Query

Let us consider a simple Dataset: ds=Dataset[{<|"a"->12,"b"->4|>,<|"a"->7,"b"->8|>,<|"b"->3|>}] Column "b" is easy to find: ...
3
votes
0answers
74 views

Data Interpolation of deaths by date

I am working with an ebola dataset from Guinea, 2014:(http://currents.plos.org/outbreaks/article/estimating-the-reproduction-number-of-zaire-ebolavirus-ebov-during-the-2014-outbreak-in-west-africa/). ...
4
votes
2answers
142 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: ...
1
vote
0answers
48 views

How to show complete dataset? [duplicate]

<|{{1, "u"}, {1, "u"}} -> {{0}}, {{1, "d"}, {1, "u"}} -> {{2 (f - g Cos[p])}}|> // Dataset gives All the items are incomplete. How to show ...
3
votes
1answer
98 views

How to get name of “named row” in Dataset for function applied to each row

After some calculations and a GroupBy I have a Dataset that is structured like this. ...
4
votes
2answers
110 views

Remove rows from dataset using query

MyDataSet[Select[#point[Fsr] == 1 &]] returns the row I want to delete, now I am trying what looks to me the most logic command to remove these rows, which is ...
1
vote
1answer
93 views

How to convert a column of a Dataset into a list [closed]

I'm loving the fact that Mathematica has finally implemented the Dataset feature, but I'm still struggling a little with it. I have a Dataset that contains a bunch of functions for different diseases ...
3
votes
1answer
66 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: ...
7
votes
1answer
119 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: ...
4
votes
1answer
88 views

Getting error message with Search on arXiv electronic preprint database

Just installed Mathematica v10.3 which has the new option to use arXiv, the electronic database. However I get an error message using ...
3
votes
1answer
87 views

DeleteMissing doesn't match in Association tables

DeleteMissing doesn't work in Association tables: ...
11
votes
1answer
152 views

The equivalent of dplyr mutate with Dataset

In R, there is a package "dplyr" that works on data.frame objects, which is one of the origins of the Mathematica Dataset construct. One of the things dplyr can do is "mutate" the columns of a ...
7
votes
5answers
528 views

How to extract points from a closed curve

OK, let's create a simple closed curve C0 = ContourPlot[x^2/4 + y^2/9 == 1, {x, -5, 5}, {y, -5, 5}]; and let's plot the corresponding points ...
7
votes
2answers
119 views

Query datasets with “variable” named slots

I want to query a Dataset object, e.g. select some entries using ...
3
votes
0answers
135 views

Best practices with HDF5 and Datasets

I work with colleagues who rely on HDF5 as their data interchange format (largely exported from Python's Pandas). Of course we ...
29
votes
4answers
2k views

How can I import a huge CSV file quickly?

I have two CSV files, each one is around 1 GB of data. When I use Import["file.csv"], it takes a very, very, long time to import the data. So how can I accelerate ...
3
votes
0answers
111 views

Dataset fails to present data in some instances when inserting new data

Update: I solved the problem: the error will occur when the length of an association is less than the length of the longest association in the association of associations In my original problem I ...
1
vote
2answers
137 views

Short way to query Dataset by the value of several columns

I learned how to query Dataset for rows that contain a certain value, but now I need to query for a long series of And in chain ...
2
votes
2answers
61 views

Converting data set from one form to another

I wish to convert Data to Data2. Both sets are provided below. Note that the second set has an arbitrary parameter "t". How can this be done. ...
5
votes
1answer
125 views

How to analyze all the data in a directory

I am trying to import, analyze, and save all the .txt files in a specific directory. I can do this with a single .txt file using the following code: ...
12
votes
1answer
322 views

best practices for saving Datasets and TemporalData to a SQL database

I have been working with a simulation tool that generates large volumes of data, and it's time to start saving this to a proper database. Is there an established mechanism for saving TemporalData ...
8
votes
0answers
53 views

Operating on a dataset named “data” triggers an error message [duplicate]

Update: With thanks to the editor, it was made clear to me that this is due to a bug in some packages autoloaded during some operations on Dataset expressions. Nothing to do with the name of the ...
4
votes
0answers
39 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): ...
1
vote
0answers
48 views

Custom drop-down list of tags for Dataset Keys similar to CountryData

CountryData produces a drop-down list of tags when you enter a string. I would like to replicate this functionality for a ...
4
votes
0answers
120 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: ...
18
votes
0answers
329 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 ...
24
votes
1answer
332 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 ...
19
votes
2answers
299 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. ...
9
votes
2answers
117 views

Using Merge[Identity] and Transpose on a Dataset

While experimenting with this answer, I ran across the following: ...
10
votes
1answer
127 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. ...