Linked Questions

2
votes
3answers
267 views

How can I assign many values each to a different variable? [duplicate]

How can I assign many values each to a different variable? For example, I want to set $a = f(1),\,b = f(2),\,c = f(3),\,\dots,\,z = f(26)$ (generally more variables than these). How can I do this ...
2
votes
3answers
428 views

How to create a writable and clearable symbol? [duplicate]

I'm trying to create several symbols and assign values to them. Here's what currently appears to work: Evaluate[Symbol["fdds" <> ToString[10]]] = 1 But ...
53
votes
2answers
2k views

Head and everything except Head?

I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical ...
9
votes
2answers
882 views

How to name a variable with the value of another variable?

A simple but very important (at least for me) question. In some languages for defining a variable, for example, we can do: i=10 "d"&i=30 So I have defined the variable d10, and... d10=30 ...
8
votes
2answers
745 views

How to Clear variables represented as a list of strings?

Say I have a string list called fullpara fullpara={"width", "long", "line", "distance"} And there are corresponding variables ...
4
votes
2answers
150 views

Can a Dynamic be attached to the single elements of a list?

Consider the following example: ...
4
votes
2answers
247 views

why set values in this way doesn't work?

question is as follows define a list ttt={1,2}; and if I set values in this way {ttt[[1]],ttt[[2]]}={3,4} then the value ...
3
votes
2answers
143 views

HoldFirst and Hold expression as argument

I store a reference to the association in a held expression in a variable: a=<||>; b=Hold[a]; And in the code, I want to do manipulations with the original ...
2
votes
2answers
1k views

Why this list has a length of 1?

Here is the code : bb = HoldForm[{aa[1], bbb[2], cc[3], dd[4]}] it returns : {aa[1], bbb[2], cc[3], dd[4]} Which is what I ...
2
votes
2answers
294 views

How to return the unevaluated variable names from a list of variables which have been declared

I feel like this should have a simple answer but I haven't found anything that works. The toy example of what I want is as follows: ...
1
vote
2answers
665 views

How to assign values to symbolic arrays [duplicate]

My main question is how to assign values to symbolic arrays, in an efficient way. The code below is a simplified version of what I am trying to do and the output I get. Note that because I am using ...
1
vote
2answers
1k views

Pass the list of variables into function to change their values

I'm new to Mathematica, so I don't really know, how do what I want, and I don't even know how to google it. Doing one Mathematica task for my supervisor, I faced the following problem. I need to ...
1
vote
2answers
190 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: ...
0
votes
2answers
714 views

How to assign the values for the Table list?

Now, I want to assign some values for a Table list and I find that If {mat[1], mat[2], mat[3], mat[4], mat[5]}={4,23,3,12,1}; it is no problem. But, if we use ...
0
votes
2answers
234 views

How do I use a passed-in symbol as a tag to define UpValues?

ClearAll@foo; foo[tag_] := ( tag /: tag[i_] := tag[[i]] ); a = {7, 8, 9}; foo[a]; a[2] I wanted the above to output 8, ...

15 30 50 per page