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56 votes

What are some useful, undocumented Mathematica functions?

Sequential With From Daniel Lichtblau's comment there is a new undocumented syntax for With introduced sometime after version ...
35 votes
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How to use Handler functions?

So I have a little bit more info, but mostly a learning technique we can test: Init I wanted to see when each of these was called so I made each possible handler (without a previous assignment) just ...
b3m2a1's user avatar
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33 votes

How can I work with RawArray?

This is a community wiki answer. Feel free to improve it. Introduction RawArray is an atomic array type that can hold data in any of the following formats: ...
33 votes
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How to use the iterator in Mathematica

Such functions set up a one-time iterator, i.e. a GeneralUtilities`Iterator. Its functionality may be inspected with ...
Michael E2's user avatar
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31 votes
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Is Internal`StringToDouble broken in 12.3?

StringToDouble was renamed StringToMReal as part of code cleanup and the addition of several friends: ...
Itai Seggev's user avatar
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27 votes

How to export an MXNet?

It seems the model file in MXNet (checkpoint) is defined by two files: a ".json" file and a ".params" file. The json file contains the definition of the network, and the params file contains the ...
xslittlegrass's user avatar
26 votes
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How to get old message formatting in version 11?

We can get old-style messages using Internal`$MessageMenu = False Needless to say, this is unsupported and undocumented functionality.
Szabolcs's user avatar
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25 votes

What are some useful, undocumented Mathematica functions?

System`Private`*Entry* functions Since version 10.0 System`Private`SetNoEntry and ...
23 votes

What are some useful, undocumented Mathematica functions?

Not sure if a new question should be started, anyway, here's some undocumented syntax (sorted alphabetically): Collect Collect ...
23 votes

Bug with iterated With: Referring to function arguments invalidates previous definitions

A long comment: Automatic renaming again: ClearAll[F]; F[x_] := Hold[With[{a = x}, {b = x}, a]]; F[0] ...
Kuba's user avatar
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23 votes
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How can I determine the type of a packed array?

We can use one of several ways. First, let us create some test data: ...
Szabolcs's user avatar
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22 votes

How to extract parts from atomic expressions like DelaunayMesh and Graph?

Motivation Recently, I wanted to extract parts of an atomic expression, and my first thought was to use a ToExpression/ToString ...
Carl Woll's user avatar
  • 131k
21 votes

What are some useful, undocumented Mathematica functions?

Undocumented option PlotPoints->{n,{p}} (see Specific initial sample points for 3D plots for discussion). with 2(!) parameters n (number of points or Automatic) and p (list of critical points) ...
20 votes

Language`* documentation project

Language`*Mutation* First seen here, implemented by Taliesin Beynon What do they do? The only functions I really know about in this bunch are the ...
b3m2a1's user avatar
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20 votes
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Why does setting SyntaxInformation add a definition to DefaultValues

In my view, the Mathematica front end would have needed a complete rewrite a long time ago to be in a shape where it can compete with modern UI's. Looking at MATLAB, it's clear that you always find ...
halirutan's user avatar
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19 votes

What is the complete list of valid FrontEnd Packet types?

I thought I'd keep a running tally of what I know about these packets (excluding the obvious ones like CreatePalettePacket) just for reference. Text / Box ...
19 votes

What are some useful, undocumented Mathematica functions?

Simplify`PWToUnitStep: ...
17 votes
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Is there any difference between Quiet and Internal`DeactivateMessages?

Internal`DeactivateMessages[expr, msg1, msg2, ...] evaluates expr after turning off the given messages. When the second argument ...
ilian's user avatar
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17 votes

What's purpose of the Internal`ToEquivalenceClass

Internal`ToEquivalenceClass[expr, tol] is used to replace floating point numbers in an expression with their equivalence class representatives according to the ...
ilian's user avatar
  • 25.5k
17 votes

Language`* documentation project

Language`*ExpressionStore This is a hash-map system (without vectorized calls) that stores items without incrementing the ref count allowing them to be garbage ...
17 votes
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Can't make more than 249 Internal`Bags in a Table

Seems to be the same underlying issue as here: by default, Table compiles its argument when the number of values is 250 or more. Evidently ...
Chris K's user avatar
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15 votes
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Reduce ODE into 1st order

Introduction I thought I would present a way to leverage built-in functions to do this. I've known for a long time that NDSolve sets up an ODE problem as system of ...
Michael E2's user avatar
  • 239k
15 votes

Using DocumentationBuild and Transmogrify to generate web docs

tl;dr The Workbench packages are out-of-date for 11.1 and the whole system is not configured to easily work from Mathematica using a structure differing from the standard ...
b3m2a1's user avatar
  • 47k
15 votes
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How to use Streaming package in v11.1?

The patch Here is a way to get Streaming` working: on a fresh kernel execute the following: ...
Leonid Shifrin's user avatar
15 votes
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A more appropriate way to use RuntimeTools`Profile

Update Here's a new version that doesn't require a stylesheet: ...
Carl Woll's user avatar
  • 131k
15 votes
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What happened to SequenceLimit?

SequenceLimit became NumericalMath`NSequenceLimit. In the past, that change broke some of the examples on ...
Chris Chiasson's user avatar
15 votes
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Internal`CopyListStructure makes fatal error sometimes

Internal context functions have been written for specific uses inside Mathematica internal code. They may expect that the input satisfies certain properties, and may crash if it doesn't. From the code ...
Adam Strzebonski's user avatar
14 votes
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Would it be a good idea to use Failure and FailureQ in own code

What I personally usually do is to still use $Failed / exceptions when a returned $Failed / thrown exception can't be used ...
Leonid Shifrin's user avatar
14 votes
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InlinePart. What is it and what happened to it?

InlinePart or @> was an operator that was introduced in one of the pre-release/betas for version 10 and subsequently removed ...
rm -rf's user avatar
  • 89k
14 votes
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What's purpose of function System`Private`LookupCodeByName and System`Private`LookupNameByCode

I tried random inputs until I got something to work. It looks like it has to do with character codes: System`Private`LookupNameByCode[200] ...
Greg Hurst's user avatar
  • 36.4k

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