# 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.

289 questions
Filter by
Sorted by
Tagged with
63 views

### How to swap keys and values of an association? [duplicate]

How do you swap the values and keys of an Association in a manner similar to taking the transpose of a two-dimensional matrix or nested list? I am trying to solve the Wolfram Challenge Capital Cities ...
66 views

### Full Information Maximum Likelihood - Under some other name in Mathematica

I have recently stumbled upon something called FIML - Full Information Maximum Likelihood. Apparently this methodology helps overcome missing variables provided the gaps are random. Searching the ...
129 views

### What Does this Syntax Mean in Ouput from DSolve?

When I run the code DSolve[y*D[f[x, y, z], z] - z*D[f[x, y, z], y] == 0, f[x, y, z], {x, y, z}] I get the following output. I don't understand this syntax. I ...
65 views

### Integrate of simple equation but is not solving!

I have this simple integral but I don't know why Mathematica can't solve it?! FullSimplify[Integrate[x/(-x^2 + a x + b)^(1/2), {x, Sqrt[b], Sqrt[R^2 + b]},Assumptions -> {a > 0, b > 0}]]
131 views

### Making a list of variables

Consider the following code, which give a Manipulate object that returns the "total" of a certain variable var 1 ...
55 views

### Extracting variables [closed]

Similar to this perhaps, but I prefer a built-in function. I have defined the expression L = a*b*c. Is there a Mathematica function that can identify and extract ...
122 views

### How to replace the arguments of a function?

I have the following type of (very long) expression: $$\ldots + X[1,2,3,5] + X[2,4,5,6] + \ldots \tag{1}$$ where $X[a,b,c,d]$ is some undefined function. I would like to replace all the occurrences of ...
90 views

### Coloring all the variables with the same name with the same color

I would like to know if there is a possibility to automatically color the variables with the same name with the same color. For example, like in the picture below: Right now I need to do it manually ...
71 views

55 views

### Mathematica says that a variable is not defined, yet it gives me a value [duplicate]

this is probably a dumb question (Mathematica noob here) but I can't figure out what's going on. I have a variable that I assign a value to and use, then later in the notebook I assign it a different ...
98 views

### Why some variables get substituted and others don't

I was running into some trouble with my math and I whittled it down to this nugget: ...