Linked Questions

26 votes
6 answers

Constructing symbol definitions for With

I would like to be able to define two arrays, one containing symbol names and one containing the values of those symbols, for use in constructs such as With. For ...
bobthechemist's user avatar
106 votes
5 answers

Replacement inside held expression

I wish to make a replacement inside a held expression: f[x_Real] := x^2; Hold[{2., 3.}] /. n_Real :> f[n] The desired output is ...
Alexey Popkov's user avatar
67 votes
4 answers

How do I evaluate only one step of an expression?

I am looking for a simple, robust way to evaluate an expression only one step, and return the result in a held form. The definition of a single step is ambiguous, and this itself is probably worthy ...
Mr.Wizard's user avatar
  • 272k
7 votes
4 answers

Delayed evaluation of assignment

I have a set of PDE's that depend on parameters. They depend on many parameters, but for simplicity we can here assume that they depend only on one, say a. I want ...
yohbs's user avatar
  • 7,046
83 votes
3 answers

Metaprogramming in Mathematica

Being functional, and having no "quotation", i.e. essentially treating data and programs semantically same, Mathematica seems naturally capable of doing metaprogramming. But could anyone construct a ...
user13253's user avatar
  • 8,666
8 votes
3 answers

Metaprogramming: creating compiled functions from inter-dependent code blocks

I want to create a compiled function from inter-dependent code blocks. Here is a minimal example showing the salient features based on strings: ...
mrupp's user avatar
  • 777
221 votes
2 answers

What is the distinction between DownValues, UpValues, SubValues, and OwnValues?

When reading through the documentation, you often encounter the phrases DownValues, UpValues, ...
rcollyer's user avatar
  • 34k
24 votes
2 answers

Pure function with attributes of arbitrary number of arguments: Is it possible?

Mathematica allows to define pure function, like Function[{a, b},Length[Unevaluated@a]{b}][1+2,2+3] (* ==> {0} *) Pure functions in Mathematica can take an ...
celtschk's user avatar
  • 19.2k
14 votes
2 answers

How can I compile this function

I want to simplify my function f1 to f2, but f2 can't be compiled. How can I make it ...
chyanog's user avatar
  • 15.6k
19 votes
1 answer

List manipulation to build a functional expression

Since Mathematica deals with Head[a, b] as an expression in this way The first Part of Head[a, b] is ...
IIIIIIIIIIII's user avatar
12 votes
1 answer

A smarter nested With?

I often find myself writing code that looks a bit like this: ...
Teake Nutma's user avatar
  • 6,031
8 votes
1 answer

Creating a Block from a list of rules

How can I create a function which works like Block but takes a list of rules as its first argument, rather than a list of assignments? The function needs to be ...
Simon Woods's user avatar
  • 85.1k
4 votes
1 answer

Generate assignment code to symbols from string

I want the function to take in string, then assign a value to its corresponding symbol. An implementation using ToExpression is ...
vapor's user avatar
  • 7,921
0 votes
1 answer

How to use Set correctly

My codes are shown in the picture attached. I'm writing codes for numerical calculations frequently, and I think it looks neat and clear to organize input parameters in the form of table. For example,...
yulinlinyu's user avatar
  • 4,835
2 votes
0 answers

Does Mathematica has any operators to program like writing lisp macros? [closed]

Lisps use read/eval, quote/syntax-quote, unquote/unquote-splicing and so on to make writing ...
cmal's user avatar
  • 191

15 30 50 per page