# Tagged Questions

Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

4answers
330 views

### Long list of similar rules

Given the following: ...
2answers
69 views

### For Loop in Mathematica {n, factored form of x^(n)-1} for 95<=n<=105

I am new to mathematica. I am trying to write a for loop to print out {n, factored form of x^(n)-1} for 95<=n<=105. I have followed the directions of another for loop, and gotten the following ...
6answers
899 views

### Can't comment strings with '*)' inside it

I believe it's a bug in notebook's comment parser. I can't comment strings with *) inside it. Something like: ...
2answers
243 views

### Associativity of /@ [duplicate]

Why are the following not equivalent: Map[Line, Map[(Print[#]; #) &, {{{2, 1}, {1, 1}}, {{-2, 1}, {3, 1}}}]] which produces ...
1answer
114 views

### Local evaluation works, CloudDeploy did not work

I a playing around with my programming cloud account. What I have found, interactive functions often are not working because there are several details that are not implemented into the cloud. So I ...
2answers
130 views

### Substitution in parameters to “Which”

Why in this expression ...
1answer
40 views

### Full superset not displayed on Manipulate slider

I wish to incorporate ODE solution with Bondary condition sets: ...
1answer
54 views

### Help for properly writing simple derivative expression

I need help to write the following expression (only 1 iteration): f(x) = ...some basic function... f[X0,...,Xp] = f(p)(x0) / p! What I have so far: ...
1answer
68 views

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2answers
65 views

### How to get the outermost command evaluated first?

I have an expression like ToString[Stuff[...]]. I plan on having the Stuff[...] be manipulated as a string according to the output of other parts of the program. The problem is that Mathematica tries ...
1answer
152 views

### Array in Sum in Minimize - error “Part specification x[1] is neither a machine-sized integer”

Help please M = 10; z = Array[x, M] {x[1], x[2], x[3], x[4], x[5], x[6], x[7], x[8], x[9], x[10]} ...
1answer
88 views

### RegionUnion issues with many Regions

The new RegionUnion[] function is just what I needed if only I could get it to work. I have many non-overlapping regions that I will need to use as plotting domains ...
6answers
638 views

### Constructing symbol definitions for With

I would like to be able to define two arrays, one containing symbol names and one containing the values of those symbols, for use in constructs such as With. For ...
0answers
42 views

### How can I mix // with a function of two arguments? [duplicate]

I often find myself using // when playing around with expressions, but it is always cumbersome to have to switch to the full notation just to apply a function of ...
5answers
970 views

### Postfix Double Slash Notation with Multiple Parameters [duplicate]

Examples A convenient shorthand that I use frequently is the "double slash" notation to string commands together. For example, I can write: ...
1answer
105 views

### How a novice user better understand the Q/A [duplicate]

A novice user reading Q/A here: I sometime need to just understand the syntax and meaning of commands exampled here. where is the best place to find it?
2answers
988 views

### Several functions in one RegionPlot with different grayscale

I try to plot the following, but something seems to be wrong in my code and I can't figure out how to fix it: ...
0answers
93 views

### SyntaxForm not correctly parsed by FrontEnd

When using TagBox with SyntaxForm, I noticed sometimes it is not well parsed by the FrontEnd....
1answer
79 views

### Appending functions to a list [duplicate]

Could someone please explain the difference between these methods, and possibly a nicer way to get the first result? (This is a toy example and in my real program I'd like to use ...
1answer
253 views

### How to see abstract syntax tree of Wolfram Language expression

I mean, suppose I have this expression: 2 + 2 I want to get something like this: Plus[2, 2] as an output. I've tried FullForm, but this just evaluates 2+2 and returns 4. Is this even possible?
4answers
364 views

### Defining a function with parameters as variables

I have an expression V = (a[1] + a[2])b[1]. How would I define a function of a[1], a[2] and <...
3answers
466 views

### Is it possible to define custom compound assignment operators like ⊕= similar to built-ins +=, *= etc?

I would like to do something like this: ...
3answers
184 views

### Is it possible to use infix notation ~ for functions with one argument or more than 2 arguments?

According to a Mathematica textbook, we can write N[x,n] by using infix notation as x ~ N ~ n. How about other functions with ...
2answers
573 views

### How to embed an image into a string?

Note: The bug described in the post is in Mathematica 9, and has been fixed in 10.0. The documentation for String contains the following statements: Strings ...
2answers
75 views

### Why can't I pass in a product of matrices in my modified matrixform? [duplicate]

In attempt to build a function that would work like MatrixForm but would wrap a matrix with brackets, I tried the following function: ...
1answer
154 views

### How would one minimize with respect to an unknown number of variables?

Say I had a function like the following: f[n_] := Sum[a + Subscript[b, k], {k, 0, n}] Such that ...
3answers
444 views

### What is the right way to write a function that includes other functions?

I want to include multiple sub functions: $b(x) = 10x$ $w(x) = s + b(x)$ $c(x) = x^2$ into two main functions: $ua(x) = w(x)-c(x)$ $ub(x) = w(x)-c(x)^2$ As a reaction to this answer, I wrote ...
1answer
84 views

0answers
98 views

### My “N” turned red randomly [duplicate]

For some reason my N function showed up in red even though I haven't noticed it in that color before. The color actually makes the code much more readable but I just don't know if I should be alarmed ...
1answer
55 views

### Correctly substituting a matrix into a scalar equation [duplicate]

I am having trouble correctly substituting a matrix into an (originally) scalar equation. For example: A = {{3, 1}, {1, 2}} cp = CharacteristicPolynomial[A, x] ...
1answer
130 views

### Highlight the same symbol throughout notebook

Once I saw people using Matlab use a keystroke shortcut that made all the same symbols as a selected symbol become blue. I am wondering is there is a function in Mathematica that is similar. If so, ...
1answer
113 views

### Does the syntax coloring I see indicate a real problem?

I need a behaviour provided by: x = 2; Block[{x = HoldForm[x]}, x] x FrontEnd marks ...
2answers
87 views

### Setting an element of an array to a value

This may be a simple syntax question, but for some reason I've been having trouble with it. Suppose we have an array arr, and we want to set one of the elements to ...
1answer
104 views

### Sort lists of vertices {indegrees, outdegrees} by indegree

in = VertexInDegree[F]; out = VertexOutDegree[F]; I want both in and out to be ordered by in. Example: graph has nodes a,b,c with indegrees 1,2,0 and outdegrees 0,...
0answers
61 views

### Why is Cell > Convert To > InputForm not invertible?

I sometimes post code to PhysicsSE, and I usually convert it to InputForm first before posting, in order to avoid pages and pages of ...
3answers
98 views

### Half kth term if n is even and k=n/2?

I am trying to write a function which will perform the equation in the attached image. So far, I have: ...
2answers
2k views

### How does one specify Neumann conditions for NDSolve?

I have a series of functions defined in my notebook, and then want to use this to solve a diffusion-reaction type equation. At the moment, something like this works: ...
0answers
436 views

### Do any mainstream text editors support Wolfram Language syntax for highlighting? [duplicate]

Syntax Highlighting for Mathematica on a Blog There is the above, but I'm not terribly excited to install rogue packages. For example on github, I share lots of Mathematica code. I see no way to ...
0answers
152 views

### Meaning of backtick in conjunction with units [duplicate]

In this fragment from an equation solution the backtick is used twice: ...
2answers
2k views

### Meaning of backtick in floating-point literal

If I compute, say, 1/3//N, Mathematica displays 0.333333 as the result. When I copy that output to use elsewhere, the paste ...
1answer
425 views

### How to plot a region bounded by three equations?

I'm very new to this website. I am having trouble plotting a 3 dimensional region bounded by these equations: ...
4answers
196 views

### How to select only NotebookObjects that are referring to ordinary notebooks? (not palettes etc.)

There is of course function Notebooks[] But, unfortunatelly it hasn't got useful options in this context. My question is how to pick ...
2answers
185 views

### Replacing a function in defined expressions

I'm having a little trouble with substituting functions into an expression. A minimal example is as follows: ...
2answers
391 views

### How can I avoid getting the error message Goto::nolabel in my code?

If anyone could suggest a reason why Label[begin] ... Goto[begin] would return Hold[Goto[Begin]], and (better) how can I avoid ...
1answer
242 views

### Issue with Compile

The following code works fine with the the function f defined as a module, however, when I convert it to be a compiled function, it gives me errors. Can some one ...