# Tagged Questions

Questions on assigning and unassigning definitions to names that represent them, including issues raised by context and localization. Use tag [assignment] for issues relating to Set versus SetDelayed.

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3answers
277 views

### How to Clear variables with apostrophe?

An apostrophe ' is often used when we want to distinguish two variables. For example, if we already have a variable t and we may ...
1answer
174 views

### What is \$ sign in Mathematica?

Is it a special sign or it can be used as anything else? For creating variables for example. \$x=4
1answer
66 views

### Why doesn't DumpSave work for elements created within a local notebook context?

I recently noticed that when dealing with notebooks with local context, I cannot successfully DumpSave variables, or, rather, when I call ...
2answers
202 views

### Mathematica does not understand (R^3)^(1/3) is the same as R [closed]

In the output from a calculation in mathematica stands a/((R^3*c)^(1/3)), with c and a ...
4answers
117 views

### Put local variables for Block in a variable [duplicate]

Is is possible to assign {x = 2, y = 3, z = 4} to a variable var so that one can write ...
1answer
67 views

### Generating a list of symbolic coefficients [duplicate]

I am trying to do something which I assume should be very simple: I want to generate a list with symbolic coefficients that looks like this: ...
4answers
112 views

### Specify a variable as an integer

I have a formula that always evaluates to a certain number for any variable X under one condition that X is an integer and ...
3answers
140 views

### How to make a defined symbol stay in symbol form?

How to make a defined symbol stay in symbol form? w = 3; g = 4; {w, g}[[2]] 3 I want the output to be ...
1answer
97 views

### How to replace variables in an expression?

I have generated a matrix using Mathematica, $\left( \begin{array}{ccc} \text{cos$\theta $} & -\text{sin$\theta $} & \text{cos$\theta $}\, \text{dx}+\text{dx}-\text{dy}\, \text{sin$\theta \$} ...
2answers
73 views

### Creating functions from output of other calculations

Apologies in advance if the title is vague, I'm not really sure what to call this. I have a function (call it 'foo') that generates a largeish polynomial, and it is natural to make the variables be ...
3answers
647 views

### Is there an equivalent of MATLAB's Workspace window in Mathematica?

For example, in MATLAB, a panel is available where one can see straightaway which variables are used and their dimension sizes. Is such a feature available in Mathematica? I really find it hard to ...
1answer
72 views

### Riffle not acting as expected [closed]

I have defined two tables: R = Table[Subscript[\[ScriptCapitalR], -i], {i, -12, -1}] T = Table[Subscript[\[ScriptCapitalT], -i, -i - 1], {i, -12, -1}] I want to ...
2answers
123 views

### Save variables values and definition

I used to do a lot of programming in R and recently switched to Mathematica. One thing that bothers me is that I haven't found a way to save variables, their values and definition! Let's look at an ...
1answer
96 views

### Proper use of arbitrary number of variables

So, I'm working on a project where the number of independent variables is not fixed. Consider a problem of $N$ independent variables, $\boldsymbol{r}$. I want to perform different things with them. ...
1answer
109 views

### Module with “local functions”

I am trying to use a Module having "local functions", i.e., those which I need to define only inside this module. So I tried this: ...
0answers
25 views

### How to define a vector of arbitary length [duplicate]

I need to use a vector of length which I can change, indexed symbolically So for e.g. when N=3 I'd like to have vec={c1,c2,c3} when N=5 ...
7answers
481 views

### How to Set parts of indexed lists?

I would like to assign a list to an indexed variable and then change it using Part and Set like this: ...
1answer
87 views

### Is it safe to assign a variable and function of the same name for different things?

I'm writing out a notebook that goes through the van der Waals Equation of State for gases, and I run into a situation where I want to assign (simplified) Tc[b_]:=5b, use that to solve for b in terms ...
1answer
63 views

### Strange behaviour of variables in Table

I'm trying to work with some vectors and have run into a strange problem. An obvious way to define a difference of two vectors would be dif[x_,y_] := x-y I ...
1answer
89 views

### Proper localization of variable names

In functions like NonlinearModelFit I need to specify parameters with a symbol name. If I localize these parameters they get cluttered in the output (e.g....
3answers
397 views

### Create an adaptive amount of local variables for error propagation

I intend to write a function which calculates the result and the error for any formula with any amount of variables using the Gauß Error Propagation. The error $dR$ for a function $R(a,b,c)\,$ and ...
2answers
263 views

### Global variable initialization in packages

Is it a good idea to Initialize variables globally inside a package ? will they be local by default to that package ?
6answers
333 views

### How to clear all variables except one?

I have a lot of variables: $a,b,c,d, \ldots$ I want to clear the values of all of them except $b$. It's really lengthy to write Clear[a]; Clear[c]; ... Is ...
3answers
376 views

### Elegant manipulation of the variables list

I have a list of global variables (some of them are indexed variables), for example: varsH = Hold[U0[1], U0[2], B0, V0[1], V0[2]] Or (if it is easier to handle) ...
2answers
130 views

### Why does Evaluate[a[[1]]]=0 assign a value to a variable while a[[1]]=0 doesn't?

I'm trying to do a small page counter with Mathematica, for leting me know about my reading progress on some books. I'm stuck on a problem: ...
2answers
237 views

### defining recursively a function with multiple if conditions

I am trying to recursively define a function which satisfies the following system of equations and which depends on two parameters $n$ and $l$,  \begin{align} A(x, n, l) &= F[ A(x,n-1,l) ]\\ ...
3answers
144 views

### how can I generate a sequence of assignments?

I want to make a sequence like follows r[1]= r[2]= r[3]= r[4]= .... r[n]= The above r[i] represents coordinates which I have ...
2answers
124 views

### How can I assign some part of data from one list to another list?

I don't know this is correct question or not,but I have a doubt. I have two Lists names are list1 and ...
2answers
260 views

### How to create a Table of Tables with indexed variables

I want to use concise code to generate a table of values that list the addition of a set of vectors. What I am looking for is essentially a Table of Tables. I will show here the kind of lists I want, ...
2answers
159 views

### Can I redefine a list as a set of variables?

Suppose I have a list mydata = {3, 14, 15, 92, 65} and in some cases I want to manipulate it as a list, like for reading from and writing to a file, or for ...
4answers
357 views

### how to differentiate formally?

I have been wrapping my head around this for a while now and I have not found a solution so far. I want to work with an arbitrary number of variables in mathematica and use some built in functions. ...
0answers
76 views

### Evaluating a function on permutations of its arguments

Say I have a function "temp" of $n+1$ variables, $y,z1,z2,z3,...,zn$. I want to test if my function has certain symmetries like swapping $y$ with square of any $z$, swapping any two of the zs, ...
1answer
89 views

### Reloading package after accidental Remove[] of symbol

I was using Needs["PlotLegends"] By chance I removed ShowLegend by Remove[ShowLegend] How do ...
3answers
212 views

### How to create functions of arbitrary number of variables?

In the following code what would be the simplest way to generalize it to say some $N_f$ number of $z$ instead of just $z_1$ and $z_2$? ...
1answer
117 views

### Using external variable as a variable inside WhenEvent & NDSolve

I'm trying to use the new WhenEvent functionality of NDSolve in Mathematica 9, in order to perform an action when a variable in the system reaches a certain value. I would like this variable to come ...
0answers
60 views

### What's the best practice for nested local constants? [duplicate]

Possible Duplicate: How to avoid nested With[]? I have many situations where I have a constant that is local to a function, with other constants that are computed from it. I see that I can ...
2answers
189 views

### local variable naming & symbolic argument

I'm stuck here with my variable assignment in this scenario ...
3answers
137 views

### Better solution than returning a list of 3 values?

I have a function (using SetDelayed) that currently returns 3 values in a list. Later on I use the result of this list along with ...
0answers
67 views

### Context “Unique to This Notebook” makes variables black even if they're not defined?

I'm trying to use this technique to keep variables separated between different notebooks. It seems to be working fine, except that variables turn black as soon as they are evaluated — any ideas why ...
0answers
58 views

### What's reliable way of finding declared but undefined functions/symbols in several interrelated packages?

I have many packages some of which use some of others. I have many symbols defined in them. Is there a reliable way of finding declared/exported but undefined functions/symbols in several ...
5answers
3k views

### How do I clear all user defined symbols?

Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?
1answer
143 views

### Is it possible to Clear all variables (but not functions)?

I have written a Mathematica script in which I define functions and variables. Here is a vastly simplified example: ...
3answers
666 views

### Why modules with no variables?

I was reading some code, in particular, recipe 4.13 on unification pattern-matching in Sal Mangano's Mathematica Cookbook, and there were many instances of Modules with no variables in them, such as ...
3answers
313 views

### Variable variable names

I have two variables, $u \in \{0,40\}$ and $\gamma \in \{0,1\}$. I take $10$ values of $u$ and $5$ values of $\gamma$ and using their combinations as a pair of input parameters, I perform some ...
1answer
182 views

### Can I create a dynamic number of rows in TabView through an iteration?

I have written code, with the help of stackoverflow of course, and I want to make it user friendly so that other people in my lab can use it. I'm playing with DialogCreate and similar functions. I ...
1answer
458 views

### Constructing variable names from a string

I have groups of descriptive variable names and dont want to write explicit code for each group, e.g. (and this is a contrived simplification) ...
0answers
270 views

### Using constraints in Solve[]

I'm not sure if the title fits. I'm basically just looking for a way to define a value and constrain it to $[a,b]$ when I use Solve later. More specifically, I ...
4answers
247 views

### How to use pattern matching to assign values to Subscript[f,x_]?

I want to define two subscripted functions Subscript[f,1] and Subscript[f,2]. To keep the assignments local, I would like to ...
1answer
152 views

### How do I use a matrix that has a variable?

I seem to be getting an error whenever I try running this piece of code. Matrix12[n_] := {{1, 0}, {0, {\[Kappa]1[n]}/{\[Kappa]2[n]}}} I've already defined the ...
1answer
178 views

### How to substitute variables in interpolated function?

I'm looking for the way to substitute variables in interpolated function again to original one. (I want to know how to get P(r, theta) from Psol(v, w).) The original variables : ...
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