# Questions tagged [assignment]

For questions relating to assignments to symbols, patterns, or expressions.

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### How to assign a value to something inside a module globally? [closed]

Let's say I created a function that calculates something inside a module. How do I assign that result to a global value? Let's say I have this: ...
1 vote
61 views

### Why =. is not clearing the value of a variable in this case? [closed]

I am reading "Mathematics and Algorithms" as part of the Wolfram Tutorial series. In "Values for symbols" section of the "Algebraic Calculations" chapter it is described ...
• 233
30 views

### ToExpression in nested Set/SetDelayed

Suppose we have the following definitions. ...
• 409
1 vote
38 views

### Manipulating the list with variables

I am trying to find the maximum element of the list for a given value of variable $c$. The example of the list is as follows: ...
• 81
52 views

### Symbolic re-assignment of products

Suppose I have some symbolic tensors $X,Y$ and I want to assign X.Y into something else without specifying what $Y$ is. For example, I may want $Y$ to serve as ...
• 242
71 views

### Problem with parametric integral with variable bounds

d[p_, B_] := \!$$\*SubsuperscriptBox[\(\[Integral]$$, $$-B$$, $$+B$$]$$Cos[ p\ x] \[DifferentialD]x$$\) Plot[d[x, 2], {x, -10, 10}, PlotRange -> Full] I ...
• 163
1 vote
40 views

### The assignment problem in Plot function [closed]

I used Mathematica to plot a system of equations: Plot[{y = 2 x - 3, y = x/2}, {x, -5, 5}, Axes -> True, AxesLabel -> {"x", "y"}, PlotLabels -> {"2x-y=3", "...
• 163
29 views

### Set keeps RHS unevaluated when RHS is a Module variable [duplicate]

Consider the simple code ...
• 912
52 views

### Assign different type of balls into output containers with constraints

The problem is to asssign all differend kind inputs to outputs. For example colored balls. On the input we can receive max 5 different type of colored balls any with amount. The amounts for the inputs ...
1 vote
33 views

### Delay evaluation of Chop until its argument has no symbols? (== has this behavior, Chop does not)

With Equal (==), if a and b are undefined symbols, a==b does not evaluate. This way we can ...
• 558
1 vote
53 views

### several actions inside If condition [closed]

Trying to write code with If, if it is correct to perform a number of actions. I am a beginner user in mathematica and not sure the form of writing are correct. What I'm asking in simple, this is the ...
• 245
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### Error message not reproduced at reevaluation, SetDelayed cache?

Mathematica v13.0: nr:=HoldForm@Evaluate@Function[t,x@t][] then evaluate ...
322 views

### Defining a function iteratively without Mathematica getting stuck in a recursion loop

I have the following code: ...
• 618
1 vote
45 views

### How can I access to the needed part of this expression? [duplicate]

I have defined a list like this: F[t] = ConstantArray[a1, 10] Now I want to assign to some of the elements the value 1; I ...
• 6,214
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### 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 ...
135 views

### How to make c[n_, x_, y_] := ToExpression["p" <> ToString[n]] = {x, y} work?

I am trying to do the following: c[n_, x_, y_] := ToExpression["p" <> ToString[n]] = {x, y} That is: Evaluating ...
• 4,911
67 views

### Forcing mathematica not to substitute some terms in an expression

I have an expression c which should be defined before the function and a function f defined as follows: ...
• 350
1 vote
90 views

### Extracting expressions from LHS of an assignment

I need to list all variables in a notebook containing several Set assignments, lhs=rhs, and equations, ...
• 433
70 views

### NIntegrate seems to not recognize multiplication of Piecewise function and f[t_]:= function, Why?

Considering inputs: vti={0, 1.5, 2.4, 5.0675, 7.735, 10}; Vscc=1.5; PSA=0.025; f=0.6; m=10; I defined a function "pwtemp2", using "FC1" and &...
76 views

### Can't create matrix function of symbolic functions and assign values to elements

So I have a problem regarding the symbolic matrix value assignment. Say I create a matrix function as: P[t_]:= {{P1[t]}, {P2[t]}, {P3[t]}}; Then I want to assign ...
54 views

### How to use Mathematica to return value from for-loop [duplicate]

I tried to use Mathematica to implement random generator. The pseudo code I use is as following: ...
• 47
51 views

### any way to store the values of the controls of a Manipulate so that one can reuse them in the future excutions

I’m using Manipulate[] to adjust several parameters, which will eventually generate some figures. After I get the desired view, I’d like to store the set of control parameters so that I can reuse them ...
• 675
54 views

### Block Behavior, but for Function Assignment instead of Variable Assignment

We can define a function using a variable b that does not appear as an argument, and then using Block, change the output of the ...
• 1,577
201 views

### Cannot assign variable value inside Do Loop

This is more of a conceptual problem. Suppose I have three lists. x1 = {1, 2, 9, 10}; x2 = {5, 6, 7}; x3 = {9, 10, 13}; Now, I wish to keep only the first two ...
• 1,092
62 views

### Avoiding For loops to perform an assignment to a variable with indices of user-choice [duplicate]

I am looking for an efficient way to perform the following operation without For loops ...
39 views

### Going between assignment rules and functions

I am trying to develop a model using Mathematica, and continuously run into difficulties going between the outputs of various functions (Solve, Differentiate, etc.) and back to functions (in the ...
98 views

### Assignment with Span to Indexed Variable

If I use span to assign a value to every element in a "column", it miraculously works: ...
• 1,680
232 views

### How can I list the common elements of two lists?

The elements of both lists are given as A={9,5,9,3}, B={9,9,5,5} In this case, how can I list the list {9,5,9} of the common elements of the two lists? (The order does not matter.)
• 1,091
1 vote
102 views

### pure function assignment

I do not understand this statement from the Introduction to Dynamic tutorial: ...
• 11
58 views

### Certain plotting functions are setting variables unwantedly

I came across the following problem. Certain plotting functions set variables to values, which I do not want. For example, if I run SliceVectorPlot3D with an ...
56 views

### How can I transform equation results into an array of values? [closed]

I would like some help. I executed the following code: Solve[Det[(s IdentityMatrix) - A] == 0] which yielded the following results at the output: ...
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61 views

### Proper way to construct a function that takes too long to plot and integrate

Consider the functions phi[t_] and psi[t_] defined in the code below. These are used as basis functions for interpolation ...
• 879
1 vote
84 views

### Fast definition of sparse tensor

I'm defining a sparse array through ...
• 469
29 views

### Extract actual result from equivalence [duplicate]

When I get a result like this {x -> -0.5 - 0.866025 I}, how do extract just the number: -0.5 - 0.866025 I. I can do this with the .rhs() method in Sagemath but I can't find the function in ...
1 vote
50 views

### Why does the delayed functional assignment evaluate to 5=6? [closed]

Why is it that x=5 x=x+1 nicely evaluates to 6, but the following ...
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### Referring to matrices with index [closed]

For exampe I have two matrices, with index 1 and 2 Mat = ConstantArray[0, {2, 2}] Mat = ConstantArray[0, {2, 2}] I wanna assign new value with ...
• 721
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### How can I get output from Reduce assigned to a variable? [closed]

I use Reduce to solve an 3rd order equation, and the output is given as the OR'd combination the solution variable. Normally, I can do a replacement to assign the value to a variable, but that doesn'...
• 187
1 vote
56 views

### How to list automorphisms on a finite set and analyze them

Let s be a finite set of integer lattice points, for example s = { {0,0} , {0,3} , {1,1} , {0,2} }. I am trying to do two things:...
72 views

### Only Reals Rules

I have a huge array of rules with many variables, such as ...
• 31
1 vote
51 views

### Errors with assigment and no errors with replacement rule, why? [closed]

So I have an expression, let's call it f11 which is a function of t of this form f11= a1*t^(-4)+ a3*t^(-3)+... and so on up until a finite positive power of t. In ...
• 165
47 views

### Using results from Nmaximize in loop

I try to Append the vector S by z+x whereby z and ...
• 335
96 views

### Assign value to the symbol returned by function

Ok, so here is example code: Clear[p, flag, k]; p = 2; k = 1; flag = True; If[flag, p, k] = 0; p After that I get the message ...
183 views

### Set value in a list at given position

Consider r = Array[Total[{##}] &, {3, 3}] (*{{2, 3, 4}, {3, 4, 5}, {4, 5, 6}}*) pos = {{1, 1}, {2, 2}}; vals={100,200} This ...
• 912
87 views

### Using a list as arguments in a function

This might sound a little silly question but I cannot get my code work. Here is the problem: I have quite a few lists of data which are basically beam profiles. I am using ...
• 37
57 views

### Number of values stored in a function

Suppose I run this: f = 1; f[n_] := f[n] = 2 f[n - 1]; f Now there will be 1001 values stored in f, and ...
• 1,073
1 vote
45 views

### How can I use Part Assignment to change sublists into other sublists (without changing levels)?

Here's a 5x5 grid. Using predefined starting points, I'd like to change some sublists into something else (e.g., the values for a color, "drawing an opaque box"). ...
• 73
557 views

### Changing value of specific element in an array. (Converting code from MATLAB to Mathematica)

Can we change the value of a specific element of an array in Mathematica? Basically, I have the following given MATLAB script which writes a big 3N-by-3N matrix $h$ by combining two 3-by-3 matrices \$...
1 vote
73 views

### Scan and Set over multi-dimensional data

Suppose I have the following: Table[x[i,j] = f[i,j], {i,1,10},{j,1,10}]; I want to set variables x[i,j] to have value ...
• 20.6k
1 vote
98 views

### Default Options not working in user-defined function for SymbolName

Abstract I have a function objectName[symbol] that returns the SymbolName as both a standalone function or when nested inside ...
• 2,009
1 vote