Questions tagged [core-language]
Questions on the basic structure of the Mathematica language (Wolfram language) including atomic data types, syntax etc
575
questions
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0
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31
views
Monitor inside core function
I like DistanceMatrix: its performance is surprisingly high, even for a big data.
However, for a huge arrays and custom ...
- 1,197
0
votes
0
answers
53
views
MinimalBy with argument and value
I need to find element of some list arr which is minimal by some function f.
But I need to get result in form ...
- 1,197
0
votes
0
answers
28
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MapApply not converting numbers as strings to numbers
I have large vectors that were imported and came in as strings. I try to convert these to numbers using MapApply of ToExpression (and the "@@@" form of this). There must be some subtle ...
- 1,579
1
vote
0
answers
32
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Can symbolic sums of indexed arrays be simplified?
As a simple example, is it possible to simplify say
Sum[Indexed[x, i], {i, 1, n}] == Indexed[x, n] + Sum[Indexed[x, i], {i, 1, n - 1}]
If not, please explain ...
- 13.6k
4
votes
1
answer
103
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Function[0], Function[,0], and Function[{},0]: Is there any inherent distinction in the "academic" sense?
Note that Function[,0] is by default interpreted as Function[Null,0].
The following three calls all give ...
- 433
3
votes
2
answers
79
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Problem with Association in DynamicModule
How can I understand the success of the first append but the failure of the second, here? (Mma 13.3.) Is there a ready work around?
...
- 13.6k
-6
votes
1
answer
67
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How to test if the input is a positive fraction?
I would like to check if a fraction is positive. The difficulty arises when there are symbols. I would like to make the assumption that all symbols, variables, and indeterminates are positive real ...
- 1,663
-2
votes
1
answer
52
views
How can I list the heads of an expression?
How can I check that a fraction contains only multiplication and power? I would like to check if it contains only the heads of Power and Times. I am wondering how to get a list of heads for a fraction....
- 1,663
4
votes
1
answer
98
views
Condition inside pure function
Why condition /; not work inside pure function?
Suppose we have:
...
- 1,197
1
vote
0
answers
48
views
Why do rules not default to local scope? [closed]
Consider the following:
80 //. a_?EvenQ -> a/2
a = 3
80 //. a_?EvenQ -> a/2
which outputs:
5
3
3/2
I think I understand ...
- 121
5
votes
0
answers
85
views
Using Cases to select expressions from a list
I am using v12.2.0 on Win7-x64. I want to use Cases to select the Times and Plus cases from ...
- 41.8k
2
votes
1
answer
120
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Why does using a variable name as pattern name determine its context?
Checking the context of a fresh variable inside Begin-End, it gives the enclosing context.
...
- 25
11
votes
2
answers
1k
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What is a function?
Regarding:
Map[#[{2, b}] &, {Reverse}]
The above works, but it makes my head spin. The documentation for Map says that the ...
- 447
2
votes
0
answers
78
views
With[{a=1},{b=a},b] in 13.2 does evaluate to 1 [duplicate]
This isn't documented, and the front end highlights the second comma and third argument in red, but it's used in DownValues[Once][[3]] and is very convenient. Anyone know more?
- 139
1
vote
1
answer
110
views
How to convert a function with named arguments to a pure function?
A function is defined with named arguments. How can this function be converted to a pure function that uses slots (#). As a simple example, how can the following:
<...
- 229
1
vote
1
answer
101
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Where does the result of thing["Properties"] come from?
Question
I'll focus on the example
stream=AudioStream@First@$AudioInputDevices
I can do stream@"Properties" to get a ...
- 3,897
5
votes
2
answers
228
views
Do not understand evaluation order of ReplaceAll [duplicate]
{x, x^2, Length@x, Subsets[x]} /. x -> {1, 2, 3}
(* {{1, 2, 3}, {1, 4, 9}, 0, {{}, {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, {1, 2, 3}}} *)
with error
What ...
- 1,197
5
votes
3
answers
285
views
Delete first case
How to delete just first occurrence of given value from a list?
Without sorting etc.
Something like this:
...
- 1,197
5
votes
1
answer
59
views
Assumptions about indexed variables
I am interested in the most efficient way to impose assumptions on indexed variables. In the following stylized problem, the following code
...
- 187
0
votes
1
answer
63
views
Using Unevaluated to get a list of symbol names
The official documentation of Unevaluated contains the following example:
...
- 5,117
4
votes
2
answers
161
views
Slots inside nested pure functions
I'd like /@ instead of Table or Map.
But let we have it inside pure function:
...
- 1,197
1
vote
1
answer
50
views
Get FullForm content
For this challenge I need to get FullForm as array, string or nested function.
Especially for number expressions.
The best I have achieved is:
...
- 1,197
2
votes
2
answers
220
views
How to implement Newton's Identities
I need to produce identities related to Newton's Identities of arbitrary order. More specifically, I need the identities in the following image for an arbitrary n:
What I can't quite wrap my head ...
- 1,516
3
votes
1
answer
89
views
How to enforce/specify the type of a module local variables similar to the module arguments?
In Mathematica, one can specify the type of a module argument by giving the Head name. I am using type loosely here since Mathematica does not have types. But this does basically the same thing. So ...
- 137k
1
vote
1
answer
55
views
VEHICLe dataset - aromatic ring counts problem
I was recently exploring the VEHICLe data set and seem to have run into an inconsistency. The dataset is described as,
The VEHICLe database, short for Virtual Exploratory heterocyclic library, ...
- 739
3
votes
1
answer
157
views
A workaround needed to overcome the Derivative function anomaly in Mathematica 13
Edits:
Additional illustrations are provided for comparison with D[] in Mathematica 12, as clarifying examples, supplemented at the end.
An erroneous Derivative ...
- 313
7
votes
2
answers
374
views
Why do some functions require its arguments to be in a list while others accept these as a sequence? [closed]
With Midpoint[{{4, -2}, {2, 5}}], the vectors must be in a list.
But with EuclideanDistance[{-2, 2}, {3, -6}], they don't.
These ...
- 599
1
vote
0
answers
46
views
Clustering related entities using the data from Wikidata
This question starts from Creating a Graph of related entities with the data from Wikidata
Compared to the previous question, I have defined a larger starting set, which I am going to enrich with ...
- 540
5
votes
1
answer
92
views
FindIsomers produces disconnected fragments
I was playing around with FindIsomers and got this strange result,
FindIsomers[Molecule["butane"]]
output
This seems unexpected in the sense that you ...
- 739
0
votes
0
answers
126
views
Codewars and Mathematica
I looked up the Wolfram Language on Codewars as the site is great to improve coding.
WL is not among the listed languages (I checked the beta versions as well). I assume this is because the language ...
- 1,596
19
votes
1
answer
758
views
When did this global rules change happen in Mathematica? Is this change documented?
In this Wolfram talk video titled "Professor Richard J. Gaylord's Wolfram Language Fundamentals Part Two" he shows at time 36:45 the following
Where there are two definitions for ...
- 137k
4
votes
2
answers
212
views
What should mapping over a number or symbol produce?
I expected it to be an error (i.e., produce an error message), but Map[f,num] is num. Why is this the correct behavior? If it is ...
- 13.6k
4
votes
0
answers
72
views
What are some basic references for learning "box language" and further mathematica language customization techniques? [duplicate]
I'd like to be able to understand and write mathematica code that is able to customize in some way the output of mathematica in notebooks, for example. I believe I need to learn the so called ...
- 41
3
votes
1
answer
184
views
BUG - Different Cloud vs. Desktop Return behavior in V13.1 [duplicate]
After install V13.1 one of my scripts get broke in my Mac. Here is the bug:
Module[{}, Return[1]; 2]
Return[1]
When I tested ...
- 26.1k
11
votes
2
answers
467
views
How can I create an atomic head or treat some head as atomic during Map?
For example,
Map[g, {0, {h[1, 2, 3]}}, {-1}]
gives
{g[0], {h[g[1], g[2], g[3]]}}
I want a ...
- 17k
0
votes
0
answers
48
views
Evaluation involving complex conjugates
I was trying to write an expression involving Conjugate. To create a minimal example, however, I have reduced it down to these expressions.
...
- 41.8k
0
votes
0
answers
43
views
Extracting function domain from a finite set of assignments
Suppose we define a function through a finite collection of equalities, e.g.,
f[1] = 1; f[26] = 321
and so on. We can extract the set of output values by running
<...
- 647
1
vote
1
answer
49
views
How to define the `Length` property of some expensive function (UpValues, DownValues and order of execution confusion)
I want to define the Length property for some function that is computationally expensive and returns a list. So if the function is ...
- 2,953
6
votes
1
answer
350
views
Is K is a function? [duplicate]
Some of the capitalized single letters are functions. Starting a fresh kernel and typing in the 24 capital letters, the following letters turn black since they are special functions,
...
- 2,079
3
votes
0
answers
73
views
Problem with Mathematica Relationship Building
When I enter the following to get Mathematica to open my pod door I get
Could someone try and replicate this? Also, my name is not Dave and I throw my own error...
...
- 7,113
4
votes
1
answer
217
views
Differences between minimization functions?
There's more than 20 functions having to do with minimization
...
- 3,897
2
votes
3
answers
222
views
How to map integration and multiplication to a serie?
*For further study of series, they can be put into a different form.
Normal[Series[1/(1 - x), {x, 0, 10}]]
This serie 1/(1-x) = 1 + x + ... ,must be first ...
- 659
0
votes
0
answers
102
views
How can I add such objects as three dots and plus
What kind of objects do the red arrows point to in the following images?
Things like the "Three dots plus". What is the name of this object and how do I insert it? And also the second ...
0
votes
0
answers
37
views
Adding new functions globally [duplicate]
Perhaps this is bad practice, but I'm wondering if it's possible to create my own Mathematica functions and make them equivalent to core functions (i.e they are available in any notebook/kernel ...
- 829
0
votes
1
answer
68
views
Applying pure function to an association, why the square brackets? [closed]
I'm studying the wolfram guide and I'm trying to figure out why the square brackets on the right side:
...
- 540
4
votes
1
answer
129
views
Creating a Graph of related entities with the data from Wikidata
I've a list of Entities from Wikidata
...
- 540
5
votes
1
answer
159
views
How can I remove First[{}] from the output list of a function?
Consider:
listOfKeys = {"Ambientalismo", "Anoressia"};
list2 = First /@ (WikidataSearch /@ listOfKeys)
I've tried
...
- 540
0
votes
1
answer
490
views
How to get a specific element from a list {a, b, c, d}? [closed]
For example, I have x ={11,12,13,14}, how do I get the element staying at the third place, that is, 13?
- 39
0
votes
1
answer
54
views
Program works, but then fails when I write it inside Module [duplicate]
I'm new to Wolfram Language; I'm trying to get used to it by writing a bunch of code and programs, being one of them the algorithm for the bisection method.
When I write the algorithm outside of a ...
6
votes
3
answers
1k
views
Can someone tell me what's wrong with this nested IF? [duplicate]
I have written a very simple nested If as follows
...
- 1,258