Questions tagged [variable]

Questions on the use or manipulation of Mathematica variables (i.e. names associated with a changeable value). Use [variable-definitions] or [assignment] for questions on variable context localization, or assignment.

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112 views

How to provide input as a set and get a set as output too?

Friends here is the code given to a problem which i have been trying to solve lately but in the first equation i want value of 'k' to be [-1,1] or it should take every value from -1 to 1. And i know ...
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5answers
1k views

Checking if all the variables are present in the defined function

I want to check if a user input the function with all the specified variables or not. For that I choose the replace variables with some values and check for if the result is a number or not via a ...
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0answers
555 views

How to declare variables with plus/minus sign as subscript/superscript?

I am pretty new to mathematica, so please forgive me if I ask any stupid questions. I want to create a vector $a^{+}=[a^+_{k-2},a^+_{k-1},a^+_{k},a^+_{k+1},a^+_{k+2}]$ and then do some symbolic ...
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1answer
69 views

converting an operation on multiple arguments into an operation on a list [duplicate]

Let's say I have an operation like Intersection[{1, 2, 3}, {1, 2, 3}, {-1, -2, -9}, SameTest -> (Abs[#1] == Abs[#2] &)] but the arguments are being ...
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1answer
104 views

Variable name complication with DSolve? [closed]

I'm trying to run the code: ...
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2answers
1k views

Can you unpack a list of values into variables in a With expression?

For instance, if I am trying to draw a graph with 5 vertices labeled a through e, and I want to draw edges connecting a and b, a and c, a and d, a and e, b and c, b and d, and c and e, I would run the ...
3
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1answer
696 views

Protected Variable Error with Workbench 3.0

I have Wolfram Workbench 3.0, build 78, with Mathematica 10.4 as the front end. I am using Windows 10. I am trying to run a simple test source code test.m: ...
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1answer
162 views

How can I solve a set of equations with variables and eliminate a few variables at the same time?

I just started learning Mathematica since I needed for my current research. I'm trying to solve a set of equations with different variables, eliminate a few variables in the set, and express one ...
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2answers
284 views

Defining a variable with comma (or any other separator) in its name?

How can I define Mathematica variable/function with comma in it? For example, defineL00,1 as a variable? I plan to use L00,1 ...
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1answer
102 views

How to call a function with an arbitrary list as its arguments inside a functional? [duplicate]

I have the following functional defined (i.e. a function of another function) where variableList contains the variable (arguments if you wish) of the ...
2
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1answer
160 views

Substituting values of variables in solution of a system of linear equations

After solving a system of 21 linear equations in 21 variables (called Xi in my code) I got the values for all the 21 variables, in the following way: ...
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1answer
290 views

An alternative to subscripts?

Are there any good alternatives to using subscripts to keep track of and uniquely identify many variables? I know that subscripted variables behave badly. Thanks!
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1answer
177 views

Checking if input is a function

I would like to write a program to find the leading coefficient of a given polynomial. (Sounds easy, right?) I'd like to be able to handle the format x^2-x+7 (with ...
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1answer
46 views

Restricting the evaluation of variables [closed]

Hopefully you understand my question. I m calculating inverse kinematics of a robot and each subsequent value is dependant on the one before. For simple porting into c++ I would like something like ...
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1answer
83 views

Manipulate different function and variable

I have list of functions such that test = {test1[a,x], test2[a,x], test3[a,x]}; I would like to plot this three function using manipulation ...
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1answer
158 views

assign a value to "elements" of a list, named as a "subscripted variable"

I'm stuck in scripting in Mathematica, since I need to assign a value to "elements" of a list, named as a "subscripted variable" (the subscript is also a variable), but it seems that in Mathematica it'...
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2answers
79 views

How to make variable values from evaluation time persist in Manipulate? [duplicate]

In the context of automatic report generation, I am trying to use a For loop to Print out a number of ...
9
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1answer
2k views

What is and isn't a valid variable specification for Manipulate?

I have an expression whose terms have arguments (representing subscripts), like this: myExpr = A[0] + V[1,T] I would like to put it inside a ...
4
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2answers
253 views

Button with loop that iteratively updates slider in Manipulate

I have the toy Manipulate. ...
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1answer
51 views

Where is the erroneous assignment that is causing my 'List of equations expected instead of tru' error?

I'm getting one those annoying 'NDSolve::deqn: List of equations is expected instead of True' errors. I have done everything I can think of to Remove and Clear all variables, including restarting ...
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2answers
564 views

Ignore some values at return

Is there Mathematica analogue of Python _ (underscore) or Matlab ~, a special variable, that can be used when a function returns ...
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2answers
161 views

PasteButton: Pasting expression name without quotation marks?

I am struggling to find a way to use PasteButton to paste the name of an expression (in particular a list) without showing the contents of the expression or without ...
5
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1answer
728 views

How to re-assign values to a List of variables?

The accepted Answer to this similar Question can only be used one time, so it's not suitable for my problem. I do high-dimensional calculations for which I need to make lists of variables, like so: <...
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2answers
396 views

How can I use an InputField value as a variable name to save to?

I'm trying to save some settings and results from Manipulate, and I want to be able to save them to different variable names. The code I have is something like <...
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0answers
90 views

Binding a variable to an unbound variable [closed]

I'm trying to do something like the following: (minimal example, f2 unbound) ...
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2answers
813 views

How to use the variables from Table in calculation

New to the site and Mathematica. I'm trying to use the finite element method to get a temperature profile. So if $q_0=f(T_0,T_1)$, $q_n=f(T_{n-1},T_n)$ and we also know that $T_1-T_0=T_2-T_1=T_3-T_2=\...
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1answer
243 views

Create a list of variables of a function

How can I create a list of variables of simple functions with arguments? These functions will be defined by the user, to be manipulated with some code later. ...
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0answers
242 views

How to list all user-defined variables with current values? [duplicate]

How to get a list of all user-defined variables and those current values in the current .nb? Maybe it's a (too) simple question, sorry if so, but the answer would help me a lot in debugging some ...
2
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1answer
373 views

Duplicate Mathematica functionality in Mathematica clone or lisp [closed]

What is the easiest way to accomplish the following in a Mathematica clone or in any version of Lisp? Also it doesn't appear in any lisps have a similar replace function. ...
5
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1answer
414 views

How to make Mathematica express an equation in terms of previously defined functions

I was given a problem for my physics class, and perhaps I have taken it too far, but I wish to finish what I started. I have a function (i warn you that this does not look pretty) ...
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1answer
111 views

Global variables [closed]

I have a workbook I am writing, there are 2 cells in it and then each cell is divided into sub cells. At the top of the first cell i made a bunch of variable assignments such as length=10, x=6, d=4, ...
2
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1answer
161 views

Assiging random values to an array of variables [closed]

I want to create a number of variables and assign random values to them. This is possible in Python using a single line of command. To be more specific say I want to create 10 variables whose value ...
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1answer
62 views

How to give more importance to a variable in a chart

I have two variables, x and y. x goes from 0 to 10, 10 being best. ...
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0answers
52 views

How to avoid import evaluation until if wil return true

My goal is to import a data from url that depends of 1 parameter, this initialy value is null or undifined en yo have to selec some popup and then the variable has value, what is the method to do that?...
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1answer
4k views

Adding letters and numbers to create a variable name [duplicate]

Let's say I have several variables, named R1, R2 and R3. I wanted to have a function ...
2
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0answers
69 views

Defining a function which takes lists as it arguments and threads over them [closed]

I want to define a function with lists as variables, which has the form like m = Table[2, {i, 5}]; f[x_, y_] = m*x + x*y; x and y are list variables; m is a ...
2
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1answer
96 views

How to choose variables of specific form

I am trying to work on a problem with a probability distribution. I wanted to get the result in analytical form. Suppose I need to keep p1, p2, p3, p4 variables such that p1+p2+p3+p4=1; How to use ...
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1answer
492 views

Is it possible to find the size of a variable in a notebook?

I have a fairly large a list of matrices matsLst, which takes about 15 minutes to compute (but computes successfully each time). I can test in the notebook that ...
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1answer
995 views

How to use Table to assign values to variables in a list?

I'm trying to do the following: R = {a, b, c, d, e, f, g, h, i}; Table[R[[n]] = RandomInteger[{0, 20}], {n, 1, Length[R]}] My intention is to assign a random ...
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0answers
45 views

Symbol-handling, force-replace instanced variables within functions! [duplicate]

Currently I am stuck with the issue of renaming an instanced variable like r1$23314 to a global one. This issue arises as I need to use a "localizeAll" Module in ...
2
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0answers
156 views

Plotting data with four variables; two labels for one of the axes [closed]

I am having difficulty related to 3D plotting task. I have a set of data points in the following form : ...
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1answer
411 views

Printing names of indexed variables instead of values

I'd like to display only the variable (indexed variable) name (in symbol form, not in string form) instead of its value in Mathematica. Say I have a variable foo[i] ...
2
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2answers
205 views

Can i change AutoStyles colors for undefined variables?

I want to change from blue to red the color of the undefined variables; but only for the current Notebook
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1answer
78 views

Can I name a variable as D(1,0,+1/2)? [closed]

I am trying to use variables with names as D(0,0,0), D(1,1/2,+1/2), etc. but I don't know how to do it.
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1answer
197 views

Is it possible to assign a value where the target is itself a variable

If I have a variable x := "a". Is there a way I can use it to assign a value to a, by just referring to ...
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1answer
269 views

Change of variables—Galilean transformation

I have a function of two variables, f[x, y], and I wish to do a Galilean transformation, i.e., y = z - v t, where ...
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1answer
2k views

How to specify the domain of a variable?

How can I specify for every expression the domain of a variable without using assumptions everytime i have to simplify it?
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1answer
142 views

How to make strong assumptions?

Or put in another way, how to make a variable behave as it belongs to a specific domain, even outside the use of simplify or other commands alike? For example: ...
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1answer
117 views

Variable change

If I have the following Hamiltonian: ...
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2answers
113 views

Solutions to multivariate equation

Is there any way to get Mathematica to give a set of solutions (pairs of x and y that are integers) to an equation with multiple variables? Something like: ...