Questions tagged [built-in-symbols]
Questions related to handling built-in symbols and functions, for example why they behave a certain (possibly unexpected) way.
221
questions
1
vote
1
answer
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views
Why does my simple string function fail to grab the only element in a List?
The idea is to normalize a string before processing it to extract information from it. Strings may come with embedded outer brackets which are easily stripped or as elements of a true list. This is ...
- 1,837
1
vote
1
answer
67
views
Ensure that Options for built-in symbols are the original defaults
I often create symbols (no args) or functions (with args) in which common options (and styles) are set in body and unique opts within args for managing multiple calls to built-in functions. these spit ...
- 1,837
4
votes
0
answers
31
views
Sequence in superscript
The code DisplayForm@SuperscriptBox[a,b,c] makes a invalid box. It still renders like $a^b$, but it's red with an error message (as it should be).
That being said,...
- 2,688
5
votes
1
answer
113
views
Evaluating PlusMinus to 2 decimal answers
How do I evaluate and expand an expression containing PlusMinus such that:
N[PlusMinus[1, 1]]
returns
2, 0
I'm stuck at ...
0
votes
0
answers
66
views
Packed/Unpacked array - what object/like 0 or 1?/how to check/ [duplicate]
In Mathematica, there is a concept called packed array.
...
- 2,877
4
votes
4
answers
214
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How to get the action diagram when the group act on a set?
I previously thought the orbital map would achieve this, but as the current answer or discuss in the comment. I realized that was wrong. And the Close behavior advice tells me "Needs details or ...
- 23.7k
1
vote
2
answers
112
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Two questions about `Infinity` [closed]
These are 2 small questions about Infinity. They are not related each other.
Q1)
...
- 2,877
6
votes
6
answers
325
views
Grouping consecutive elements at specified positions
Let
L1={1,2,4,6,8,9,10,14,15,17,21,22,72,76,80,96,106,116,117}
Question1) Group from 10-th to 14-th elements in L1.
So that the ...
- 2,877
3
votes
1
answer
75
views
Extracting list structure from nested list
Can we construct a function f, g in mathematica such that
For any list L,
g[Flatten[L],f[L]] ...
- 2,877
1
vote
2
answers
74
views
Theoretical Timing possible? (not changes for each evaluation)
Is there a method to measure theoretic time load (hope +theoretic memory load) of an evaluation?
They should not change - always generate same value after pressing Enter key(=evaluation).
Hope they ...
- 2,877
9
votes
3
answers
367
views
Construct a pure function containing built-in 'Sequence'
I guessed the output for
(Sequence[#, 7]&)[3]
should be
Sequence[3,7]
But my guess was wrong. See the screenshot:
And I ...
- 2,877
2
votes
1
answer
326
views
1
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1
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129
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The square of Abs of a complex number
We all know that
4^2 + 22^2 = 500
Is there a natural way to generates 500 from the complex number ...
- 2,877
0
votes
0
answers
70
views
Calculate the "intersection" for the given case?
Consider the following task:
There are two cross-sections: the first one is located in the $yz$ plane (the case 1), and the second one is in the $xy$ plane (the case 2). In the spherical coordinate ...
- 3,832
6
votes
1
answer
113
views
What is the purpose of StrokeForm?
Symbol System`StrokeForm is present already in Mathematica version 8 (but not in version 5.2).
Currently, it is used in built-in themes, for example:
...
- 56.2k
0
votes
1
answer
42
views
Using the symbol of the system of equations [duplicate]
Part 1
I'd like to know how to use the symbol of system of equations (left curly braces). I tried the following code:
Part 2
How can I add a third equation?
- 929
0
votes
1
answer
103
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Symbol of system of equations
I'm wondering if there is a way to use the symbol (the left curly bracket) of a system of equations. So far I found only the following "symbol":
I need to remove the two conditions.
EDIT2: ...
- 929
2
votes
1
answer
77
views
Is there a comprehensive list of most common or most important native Message-s (w/tags) for errors and Failed?
Yes I understand how to use Messages[symbol] but that doesn't help much. I have no idea which important ones I may have missed in my search or even how many exist. ...
- 1,837
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1
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49
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How can I clear the symbol \[ImaginaryJ] for use for another purpose?
By default it is the same as imaginary unit, but I want to use it for split-complex numbers.
- 2,751
1
vote
0
answers
130
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Separate colours of an image
Since LAB colour space is based on opponent color theory, an image in 'LABColor' is made up of red/green, yellow blue separations.
I am trying to separate an image into its distinct colour components (...
- 7,759
0
votes
2
answers
94
views
NMaximize - global maximum fail - How to?
Problem :
Let x,y,z be non-negative real number whose sum is 1.
Find maximum of 0.2x + 0.2y + x^2*z + y*z^2
What I did first was reducing variable.
...
- 2,877
4
votes
1
answer
287
views
Largest k such that p^k divides n
(Here all variables are integer.)
Is there a built-in function f[n,p] such that
f[n,p] = largest k such that p^k divides n
For ...
- 2,877
2
votes
1
answer
88
views
Can I tell whether a symbol is build-in (part of the System` library)?
I'd like a function that checks whether a symbol is a predefined part of the language or not. More generally, it might check whether it's part of a given package.
...
- 862
3
votes
2
answers
129
views
Built-in functions on the LHS won't pattern-match
I have this pattern-matching problem:
F[X_,myminus[X_]]:=0
F[1,myminus[1]]
Works.
...
- 887
7
votes
4
answers
380
views
AnyTrue is too good (compared to MemberQ)
Let L be a list of integers, and ⓝ denote an explicit integer.
I've thought the most natural way to tell whether ⓝ belongs to L is
In[1] MemberQ[L, ⓝ]
But there ...
- 2,877
3
votes
0
answers
56
views
Definition of large expression - makes PC freezed
In[1] A=Range[10^4];?A
Out[1] (* definition of A*)
It works for 10^4. But if I increase the number to 10^6
...
- 2,877
2
votes
1
answer
72
views
Construct really identical function (the same as Length)
In[1] Length[Unevaluated[1 + 1 + 1 + 1]]
Out[1] 4
Q1) Can we construct a function named f, such that ...
- 2,877
0
votes
0
answers
53
views
Check an input matrix M contains any nonzero diagonal matrix element or not
Is there a way to easily check an input matrix M contains any nonzero diagonal matrix element or not?
For example,
if the M contains any nonzero diagonal matrix element, Output: True.
if the M ...
- 101
2
votes
2
answers
136
views
Get list of special characters
I recently found that \[Gradient] and \[InlinePart] both expand (contract) to special symbols in MMA.
So far as I can tell (see ...
- 2,688
1
vote
0
answers
79
views
Is there a function in Mathematica to combine/decompose sinusoids? [closed]
Lets say I have some combination of an arbitrary number of sinusoids with potentially varying magnitudes, phase angles and frequencies that I would like to compose into a singular sinusoid, is there a ...
0
votes
0
answers
47
views
How to reconstruct a complicated built-in function (e.g. for modification or use in a version that does not have it yet) [duplicate]
Is it possible to extract the definitions for a built-in function to reconstruct a similar user defined function. This would be useful to port new mathematica functionality to older versions or to ...
- 3,603
8
votes
1
answer
474
views
very simple but unexpected aspect of Function[ ]
I've always thought
(2#+1)&
and
Function[x,2x+1]
are interchangeable in common sense. But,
...
- 2,877
0
votes
0
answers
66
views
0
votes
0
answers
45
views
What could go wrong in redefining Power to act on functions?
Inspired by a tweet (from a locked account, unfortunately, so I can't link it), we can get notation like $\cos^2(x)$ to work in Mathematica in general:
...
- 8,208
1
vote
1
answer
70
views
How to define distributivity of CenterDot on bras and kets
I am working on a code for a coupled quantum harmonic oscillator and found myself in a hiccup when trying to evaluate the inner product of linear combinations of bras and kets. I have initially ...
- 13
3
votes
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79
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16
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1
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298
views
Head[x] vs x[[0]]
Can we say Head[x] and x[[0]] are identical ?
In mathematica manual I could find : 'The head is the part with index 0'
But I am not sure whether Head[x] are x[[0]] are really interchangeable in any ...
- 2,877
2
votes
2
answers
69
views
A condition for the given point to be included in the domain?
If we have two domains, it is possible to check whether one domain is inside another domain:
...
- 3,832
3
votes
2
answers
97
views
A condition for one domain to be included in another domain?
Consider two domains:
domain1 = Rectangle[{-2.5, -2.5}, {2.5, 2.5}];
domain2[R_] := Disk[{0, 0}, R]
I would like to check whether the second domain is completely ...
- 3,832
2
votes
1
answer
113
views
How to find the area of circle inside the rectangle?
Consider a circle located at the origin
circ[R_] := Circle[{0,0},R]
and an arbitrary rectangle
...
- 3,832
0
votes
0
answers
57
views
Dot Product doesn't behave like normal function
I am trying to slightly modify the Dot function by treating it like a usual function, but soon I notice something weird about it.
Suppose there is a set ...
- 381
5
votes
1
answer
79
views
Counting the number of edges between two graph partitions
Consider the following:
g = RandomGraph[WattsStrogatzGraphDistribution[1000, 0.1, 5]]
comm = FindGraphPartition[g, 2];
CommunityGraphPlot[g, comm]
...
- 55
2
votes
1
answer
154
views
How &@ and &/@works?
I have the following expression:
(Join[#, Reverse[#, {2}]] &@Partition[#, 2, 1, 1]) & /@ Vec
(* where: *)
Vec={{2,0},{1,1},{0,2}},
but I am not sure how ...
- 657
2
votes
3
answers
370
views
Compare all elements of a set with a specific number and return 1 or 0
Say I generate a set of 20 random numbers by x=RandomReal[{0, 1}, 20], I want to compare every element of x with 0.4. If it is less than or equal to 0.4, then return 1; if it is greater than 0.4, then ...
- 111
0
votes
0
answers
63
views
Avoiding Tables, Do and other loop construction
In my work I have a lot of cases, where I should calculate non-listable functions for a quite large number of points. To be more concrete, consider first listable function ...
- 719
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0
answers
92
views
How to figure out syntax for symbols?
I'm new to Mathematica and am having a hard time figuring out how to type certain symbols when I read the documentation.
For example, in https://reference.wolfram.com/language/ref/...
- 43
16
votes
3
answers
982
views
Which function names have been re-purposed in Mathematica after being deprecated?
I have just learned about the new function Splice from this answer. It turns out that this function used to have a completely different usage! (See below.)
To me, ...
- 21.6k
11
votes
1
answer
464
views
Finding year that MMA functions were introduced via programmatic calls in the Wolfram Language [duplicate]
Is there a way to find the year that MMA functions were introduced via programmatic calls in the Wolfram Language? I would like to be able to create and manipulate such a list or dataset.
- 1,412
4
votes
0
answers
44
views
What built-in functions have bad time/space complexity and their alternatives?
It's surprising that Join is $\mathcal{O}(n)$ (due to copy) while I've been using it as a convenient way to join lists together. It also reminds me of suggestions ...
- 1,950
3
votes
1
answer
124
views
How can I prevent TabView from resetting the current tab?
This is a simplification of a problem that has arisen in a project regarding Euclidean activities for verifying proportions via operations
on pairs of magnitudes. In the project, the LocatorPane is ...
- 16.3k