Questions tagged [assignment]
For questions relating to assignments to symbols, patterns, or expressions.
230
questions
1
vote
1answer
25 views
Setting a function equal to another function then Clearing the latter
I have a loop in which several values of a function are computed, depending on the values for that function that were computed in the previous iteration of the loop. This could be implemented ...
1
vote
1answer
39 views
Set: in part assignment is not a symbol [closed]
This is probably a basic question but I am new to Mathematica, so please help me out here.
I have the following piece of code:
...
2
votes
2answers
45 views
Cannot understand meaning of “identical”
This came up in the context of plotting solutions to NDSolve, but I've reduced it to the following issue. This really has me scratching my head.
...
4
votes
2answers
71 views
Using pure functions to assign a value to variable depending on whether it has been defined already
Let's say I want to assign to a variable the value $2020$ if it has not already been defined and do nothing if it has. In short, for a variable $a$, I want to achieve the functionality of ...
6
votes
4answers
182 views
Assigning a string to variables names
I have the list
n1 = {{REL1, "REL.csv"}, {RAND1, "RAND.csv\"}}.
That is {{variable name, string}, {name, string}}. I want ...
2
votes
1answer
37 views
Problem with superscript
I would like to know if there is option to make such scrpits like in this picture below.
Is option to put letter instead of a *?
0
votes
0answers
4 views
Assigning a solution to variables [duplicate]
I have solved my solution and it has been appeared, it is C1, C2, C3, C4 but when I call C1 again (%13), program shows me that C1,... is not assigned. How can I reapair that ?
4
votes
1answer
75 views
Why the difference in performance? Array vs List and `Delete` vs `Nothing`
In a previous question I was warned against the use of Nothing to delete elements from a list, and rather use Delete. Being of ...
7
votes
1answer
98 views
How would you explain Nothing[] weirdness? [duplicate]
I would like to use Nothing[] to make some elements of a list invisible. (The intended use is to remove a few unwanted points from a ...
8
votes
1answer
123 views
Why Optional in Set is not held by the HoldFirst attribute?
When evaluatingf[x_:x0] := x, x0 will be evaluated, regardless of the HoldAll attribute of <...
4
votes
2answers
170 views
Using module to define a function that calls another function: Should i use set-delayed (:=) or set (=)
Suppose that I have a function
f[x_,y_,z_]=x*y*z
and now suppose I want to consider a specific application where z is a ...
1
vote
0answers
59 views
What does a single vertical bar mean in ConditionalExpression? [closed]
I got the condition below as part of a ConditionalExpression. Those single vertical bars before and after $\frac{1}{k1}$ appear to be an absolute value but I don't ...
0
votes
2answers
103 views
Assign FindRoot output vector to a vector instead of element by element
Using FindRoot to solve a multivariate equation system, assigning the output to variables one by one works, but assigning the output vector to a vector gives the ...
0
votes
0answers
25 views
Performing operations on LHS of assignment [duplicate]
Is it possible to first perform an operation on LHS of the = symbol, evaluate that, and then assign the RHS to the new LHS as usual? The following shows the most ...
1
vote
2answers
58 views
Assigning values to multiple variables from a list
I have a solution of the following form:
$F(x)= \\
\qquad c+(x_0+x_1+x_2+\ldots +x_n)- \\
\qquad (x_0\,\log(x_0+\sqrt{x_0})+x_1\,\log(x_1+\sqrt{x_1})+x_2\,\log(x_2+\sqrt{x_2})+\ldots +x_n\,\log(x_n+\...
5
votes
1answer
98 views
Setting options of object after defining it
Is it possible to edit the options of an object like Plot or Graphics after I store it as a variable?
For example, consider the ...
1
vote
2answers
27 views
Assign numerical values to symbolic variables in a vector inside a do loop
I have vector k = {k1, k2, k3, k4, k5, k6}.
I would like to assign numerical values to the elements of k in each step of a <...
0
votes
1answer
53 views
How to turn a matrix into a 'function'? [duplicate]
I have some codes to turn a set of equations into a matrix. Suppose the matrix Lis expressed in terms of variables $\epsilon$, $K$, $M$, and I want to make a ...
3
votes
2answers
150 views
What is the point of tagset /:? [duplicate]
I'm teaching myself Mathematica and came across tagset.
So I followed the example in the link, but seem to be missing the point. All of the below give me the same answer after assignment: that ...
1
vote
1answer
48 views
TagSetDelayed for spotting zero derivatives
I am trying to implement my own differential operator, d[arg_, var_],
that computes the derivative of arg w.r.t. ...
1
vote
1answer
41 views
Part Assignment of variables with argument
I do not really understand why this:
a = {1, 2, 3};
a[[1]] = 3;
a
{3,2,3}
works as desired, but this does not:
...
2
votes
1answer
32 views
SetDelayed error for Derivative rule
Having a delayed assignment of the form
Derivative[1][f][x_] := HoldForm[f[x]]
works. But if there is a delayed assignment for f as in
...
0
votes
0answers
23 views
Approximating the density of an arbitrary set using an arbitrary Folner Sequence of its superset [duplicate]
How do we use Programming to approximate this limit
where is the density of in , is the Folner Sequence of , is an interval with , and . For more information, click on this link (replace G,X,i,g ...
8
votes
1answer
139 views
Error Message when nothing should be evaluated
When I try to define this simple function
getCoeff[SeriesData[_, _, coeff_, _, _, _]] := coeff[[2]]
I get an error:
...
1
vote
1answer
63 views
ContourPlot a list of equations generated by the Table command
The first command below produces proper contour lines while the second command produces an empty plot. I would think that the two commands should produce the same output. What's going on?
...
0
votes
0answers
26 views
Defining a function from an evaluated function stored in a variable
I have the evaluation of a function b, stored in appo. Now I want to define a new function f ...
0
votes
2answers
78 views
Monte Carlo Method [duplicate]
How do you use a Monte Carlo method to approximate the area enclosed by the circle.
2
votes
0answers
34 views
Mathematica: Remove argument from object with flat attribute
I have an object in mathematica with the attributes Flat and OneIdentity. I also defined the following substitutions:
...
3
votes
1answer
61 views
Combining `With`, `If` and SetDelayed
I just noticed that
With[{x = 1}, If[x == 0, 0, 1]]
returns 1 (as I expected) but
...
1
vote
1answer
43 views
Drop-down menu to globally change definition of a function `t[x]`?
If have a function t[x_] which is used extensively in a long notebook, but which has a variety of definitions, and which is used in a variety of ways. I'm looking ...
0
votes
2answers
28 views
How to select certain numbers to assign a new value and others still keep same
For an array TestA={15,12,5,8,6}, I want to change the value of number greater than 10 into 0, as TestB={0,0,5,8,6}. When using "Select" command, I will lose some numbers.
Thanks.
1
vote
1answer
39 views
Vector shape and Dimensions
I think I have not understood clearly the difference between dimension and shape. I want to construct a vector remembering recurrence of the type :
...
2
votes
0answers
32 views
Programmatically Inject Logical Vector into Manipulate Checkboxes or Vice-Versa
I am building a large Manipulate application with about 50-60 checkboxes through which the user can select entities to be drawn on a main canvas. The main drawing routine, called from within ...
1
vote
2answers
77 views
Error in Assignment
I want to create a matrix with each element updated as per the formula, whose inputs are dependent on the location of element in the matrix.
...
1
vote
0answers
29 views
Un-assign MenuCommandKey
In my StyleSheet, I would like to assign to the environment Subchapter the Key Alt+2 (via MenuCommandKey. However, this is ...
1
vote
2answers
98 views
How to assign output of `Last@Reap` to a variable? [closed]
I would like to define a variable that equals the solution of a numerical equation. Usually something like smax=zmax/.FindRoot[Exp[-zmax/2]==2,{zmax,0}] would work. ...
1
vote
1answer
49 views
Why does it fail to assign values to variable in Grid? [closed]
I have a grid such as the following, and want to assign the values in the second row to the variable in the first row, but it always fail, can you provide a solution? Thank you!
...
0
votes
1answer
45 views
I am asserting a variable in Mathematica as Real yet it is not implementing it!
Element[\[Theta], Reals];
Ga = g;
Gb = g*Exp[I*\[Theta]];
{{Conjugate[Gb], Ga}, {Ga, Gb}}
I have a code as such for a matrix as given above. as ...
0
votes
0answers
209 views
Assign a Derivate to a new fuction variable
I'm having a new problem. I'm trying to create a new function from a Derivate of another function, but i'm can't getting it. Someone could help me? I'm thinking that is something in the syntax of the ...
4
votes
4answers
148 views
Is it possible to create lookups on temporary symbols that still allow the symbols to be automatically removed?
Is there some way to create lookups keyed on Temporary symbols that somehow avoid the referencing of the Temporary symbols, ...
1
vote
2answers
31 views
A question about a replacement of element of set
To begin with, I'm a poor English speaker, which means it would be hard to read to natives...
I was trying to memorize mRNA codons with mathematica.
...
1
vote
1answer
71 views
How to use an up-value assignment when all symbols are “too deep”?
I would like to make an up-value assignment such as
a/:Conjugate[a[x]]a[x]+Conjugate[b[x]]b[x] = 1
or
...
0
votes
1answer
57 views
Replace constant in summation function using replace or If or /
Hi i how do i replace constant for k in this summation.
For following:
Even 2*n Even replace k by a
Even 2*n+1 Odd replace k by b
Here is the code
...
1
vote
0answers
57 views
Making a function definition where the right hand side is evaluated before the definition is saved [closed]
My question is about assigning the resulting expression after evaluation of a function.
So what I want:
FOCf[x, y] := D[f[x, y], x]
such it immediately ...
3
votes
2answers
421 views
Is it possible to set values for a list of variables using a for loop? [duplicate]
Let me preface this question by noting that this is a simple example meant to clarify what I am asking. The actual context in which I want to implement this involves associations containing hundreds ...
4
votes
2answers
168 views
Scoping of pattern variables [duplicate]
I have run into a problematic behavior, and then came to find that it is a "possible issue" called out in the documentation, but I guess I am just baffled that this IS an issue, and am wondering why. ...
-1
votes
1answer
62 views
Why it is doing part assignment? [closed]
I am writing an algorithm and need to keep updating an association called "verticesAssoc". My algorithm ran perfectly at first. However now I want to use the same algorithm on another association "...
0
votes
0answers
21 views
Seeing definitions of built-in functions [duplicate]
Possibly a very amateur question, so I'll apologise in advance. I'm reasonably new.
I'm trying to write a Dot equivalent of ...
6
votes
1answer
64 views
unexpected result from augmented assignment to association
Is the last of these results expected? If so, how?
...
3
votes
2answers
182 views
Transferring DownValues
I have a code in which I define something like this:
cc[1, 2] = 1;
cc[2, 6] = 12;
cc[3, 7] = 3;
After some manipulation I define a sort of temporary variable ...
