For questions relating to assignments to symbols, patterns, or expressions.
57
votes
2answers
2k views
What is the distinction between DownValues, UpValues, SubValues, and OwnValues?
When reading through the documentation, you often encounter the phrases DownValues, UpValues, ...
8
votes
3answers
2k views
Assign the results from a Solve to variable(s)
I understand Mathematica can't assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables?
5
votes
3answers
537 views
Assigning values to a list of variable names
As part of a calculation I need to do something like this
Evaluate[{aaa, bbb, ccc}[[ index]]] = {1, 2, 3, 4, 5}
so if index is ...
11
votes
5answers
620 views
How to pass a symbolname to a function with any of the Hold attributes?
Given a function with the attribute HoldFirst, HoldAll or similar, and a variable, list, how ...
8
votes
3answers
217 views
How to write a function-defining function which stores the function arguments in a stack?
I have a function-defining function
SetAttributes[DefFn, HoldAll];
DefFn[f_[args___], body_] :=
f[args] := body;
I am trying to modify this function to record ...
16
votes
1answer
340 views
How do you set attributes on SubValues?
SubValues, as discussed in a previous question, are declared as follows
...
9
votes
2answers
240 views
Scoping in assigning a derivative
While answering another question, I stumbled upon a problem I cannot easily resolve.
To assign the derivative of a function to another function, typically one can do this with a ...
11
votes
2answers
172 views
Nested definition: How can I define a function with a passed-in expression?
Here's a simplified version of what I'm trying to do:
...
10
votes
1answer
157 views
Does Set vs. SetDelayed have any effect after the definition was done?
I was always assuming that the only difference between Set (=) and SetDelayed (...
12
votes
1answer
195 views
How to make a function like Set, but with a Block construct for the pattern names
How can we define a function that works like f[x_]=ComputeSomething[x] and treats x as a variable that does not have a value? ...
4
votes
2answers
140 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 ...
22
votes
1answer
404 views
How to augment the realm of functions Mathematica thinks it knows how to integrate symbolically
My question involves extending the functionality of Integrate over specific integrals in the most generic manner.
Specifically, is it possible to "hack into" ...
15
votes
2answers
166 views
Clearing a specific definition
Consider the case where a symbol has multiple definitions attached to it,
a /: Subscript[a,2] := 1
a[b_] := 2
a[b_, c_] := 3
How does one clear (/unset/remove) ...
14
votes
5answers
275 views
16
votes
4answers
476 views
How can I randomly generate a unique, unused symbol?
In a previous question on collecting terms for a multivariable polynomial, I answered with a solution that required a unused symbol to be used for a temporary substitution and back substitution.
It ...
11
votes
3answers
167 views
MapThread gives different results from ToExpression when trying to assign variables from a list
I have the following data set:
data = {{"Jakarta","Surabaya","Bandung"},{1,2,3}}
and I'd actually like to assign the numerical values to the categorical data so ...
1
vote
1answer
98 views
direct assignment to the element in a Table
I have already asked a related question here why set values in this way doesn't work?
But I think I have to write the question which I encountered explicitly?
...
