Questions tagged [query]
The query tag has no usage guidance.
69
questions
2
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2
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Write an expression that queries all of MMA to find the top M Symbols with the most Options or M Symbols having N Options?
I apologize, but I'm way over my pay-grade on this one, so I don't have any code to share that needs correcting. That is because I really don't know how to start this. I feel like this has a very easy ...
- 2,337
4
votes
1
answer
120
views
Apply TimeSeries onto one or more Dataset Columns
I recently responded to a question on Wolfram Community. My solution works, but I believe it could be improved. I'm trying to apply a TimeSeries to one or more ...
- 1,180
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0
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51
views
How to search exact product title with ServiceExecute
I am trying to find the exact product title having phrase "HEPA filter bags" on "amazon.com" but it doesn't return the correct result.
...
- 125
4
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1
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78
views
How can default valued be added in a Query?
I'm not understanding the the default values are not used to produced a length of 0 in the following example. What is the right way to add default values during a query?
...
- 13k
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25
views
How to specify authenticity of SSL for querying APIs?
While ago I was using this command with no issue, now I have an SSL error:
...
- 435
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2
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151
views
9
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1
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203
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Generating Google BigQuery API Access Token in Wolfram Language
I'm working on a Wolfram Language Package to connect into Google Bigquery (that I'll make public available). In order to finish It, I need to solve a last step, that is how to get an authentication ...
- 25.8k
4
votes
2
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176
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 ...
- 440
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1
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170
views
2
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0
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56
views
3
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126
views
Efficiently get positions of Query results
I have some very large Datasets. Is there any efficient method of getting the positions of results found in a Query? That is, without using ...
- 3,637
4
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1
answer
107
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.
...
- 231k
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0
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31
views
Can the following operation be performed in a single query without using explicit Maps or nesting Queries?
Is there a way to include the function StringPosition["e"] inside the Query in the following:
...
- 8,667
1
vote
1
answer
79
views
A more efficient way to interrogate data inside a Dataset: a generic relational map
I have a Dataset that stores the relationships between people IDs (in columns) and the events they attended (in rows). I want to produce a linear text report of those relationships.
How can I do this ...
- 163
13
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2
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348
views
Does anyone know a way to use patterns in Query?
This question is a follow up from my previous question.
Query has a nice syntax that allows it to apply functions on association based on specific ...
- 8,667
3
votes
3
answers
1k
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Select specific rows of a dataset
I am struggling with extracting specific rows from a dataset.
...
- 177
8
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2
answers
274
views
How does Query decide the order in which the functions are applied?
First of all I know that Query is a nice way to organize your functions that are applying at specific levels of an expression. But I don't understand the order in ...
- 8,667
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1
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183
views
Using Semantic Import to do an Excel-like VLookUp using Mathematica
I'm following an example provided in the following
Stack Exchange Link
but, using a different approach. My data is contained in an Excel workbook called "Input Workbook.xlsx"
as shown here:
I ...
0
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1
answer
118
views
4
votes
1
answer
92
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 ...
- 15k
5
votes
2
answers
127
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 <...
- 8,667
8
votes
2
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184
views
Query inside Dynamic triggers continuous high CPU load for FE
Here is a (vicious) problem I am able to reproduce with v12 and v11.3 (previous versions not tested) and OSX.
This is a minimal example to demonstrate it (even if it seems useless here I do need <...
- 7,400
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53
views
How do I Select when the key of an association is a multi-word string [closed]
I have imported some survey responses into a Dataset. I now want to select those rows where the response to "participant type" == "Virtual". I discovered that this ...
- 257
4
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2
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113
views
Simple dataset query
Why does taking a Part fail in a Dataset query function when there is an operation in the index argument?
...
- 6,161
2
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1
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160
views
0
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1
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184
views
Aggregate function problem
I use a function to do something similar to a SQL sum. I've asked about simplifying it in another post. I'm still using this function and it works well for aggregates like ...
- 3,656
5
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1
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98
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:
...
- 30.8k
2
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0
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37
views
Keyed eigensystem for nested Association
Suppose a matrix is given where both rows and columns are keyed, for example this correlation matrix:
...
- 15k
2
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1
answer
75
views
Handling Missing values flexibly in Query (MissingBehavior problem)
There’s an inconsistency in how Missing values are imputed in Query, with ...
- 15k
6
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1
answer
327
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3
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1
answer
177
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 ...
- 10.7k
7
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3
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364
views
Applying a function by Key pattern, preserving Association order
Any convenient ways to apply a function to Keys that match a pattern in an Association? Method should handle:
Mixture of ...
- 15k
8
votes
1
answer
88
views
Unexpected behavior of PreIncrement when querying associations
For reasons I won't go into here, I became curious about the what would happen should I make a query that applies PreIncrement to one key in a list of associations....
- 107k
4
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0
answers
112
views
How to get parent key in Query on Association/Dataset?
Is there a general and terse method to obtain the parent key of the current "position" in a Query of an Association/...
- 40.6k
4
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2
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36
views
How to Quiet an operator to avoid Query fail
This Query fail, due to divide by zero error message...
<|"a" -> 1, "b" -> 0|> // Query[#a/#b &]
Missing["Failed"]
...can be prevented by ...
- 15k
8
votes
1
answer
442
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 ...
- 15k
3
votes
1
answer
89
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:
...
- 15k
9
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2
answers
195
views
Getting slices of a nested Association via Query
I'd like to get specific slices from a nested database-like Association through Query. Take for example this toy database of ...
- 8,319
3
votes
2
answers
147
views
Composition with Transpose failure with Dataset
Is the failure of the 2nd Transpose here a known bug?
Dataset[{{0, 10}, {2, 11}, {3, 12}}][
Transpose /* Map[MinMax] /* Transpose] // Normal
...
- 15k
11
votes
2
answers
277
views
Simplifying a reverse Fold for a Query
Is there a simpler way to parametrize this tail-recursive expression to be applied as a Query (for processing a nested ...
- 15k
9
votes
2
answers
262
views
Slicing an Association with named key span without normalizing?
Is there way to slice an Association with named key span?
Span currently doesn't accept named keys:
...
- 15k
22
votes
2
answers
397
views
Query: adding additional operator changes meaning of preceding operators
Consider the following query:
Range[5] // Query[Select[EvenQ] /* Append[1], f]
(* {f[2], f[4], 1} *)
It selects the even numbers, applies ...
- 67.9k
3
votes
0
answers
66
views
Aligning input form of a sequence of Queries
Is there a way to modify the parser, or define options, to align the indentation of a sequence of Queries on a Dataset?
Given:
ds = <|"a" -> 1, "b" -> <|"c" -> 2|>,
"d" -> <|"e" -> 3, "f" ...
- 15k
12
votes
0
answers
179
views
Unix-like reference to parent and root Association?
Is there a syntax or function to reference parent and root when querying nested Associations similar to Unix' ".." and "/", eg "cd ../../mydir". ?
Here's a typical application of the root construct....
- 15k
2
votes
1
answer
361
views
Query and Dataset Syntax Peculiarities
Question
Can someone please explain to me the syntax of Query and why its behavior is so befuddling to me at the moment?
I am going to go through a few simple ...
- 5,282
11
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2
answers
213
views
Large Dataset query fails if column contains Missing
In version 11.0 (Win 8.1 Pro) a query on a large Dataset for a column that contains Missing fails most unceremoniously.
With
<...
- 40.6k
4
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1
answer
188
views
6
votes
1
answer
118
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Mapping (Query) a function at multiple locations in nested data via All, Span
For this data:
dt = <|"a"-> <|"x"-> 1|>,"b"-> <|"y"-> 2|>,"c"-> <|"z"->3|>|>
It’s awkward when mapping the same ...
- 15k
11
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2
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201
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:
<...
- 9,939
7
votes
2
answers
157
views
Nothing in a Query
In Mathematica 10, Nothing is defined as to automaticaly disappear when used in a list or in an association, and moreover with the property that it returns ...
- 9,939