89k 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? ...
127 views

How to define a version of Table[] which localizes iteration variable by Module[]?

For reusable code it's good practice to use Module[] to localize iteration variables used by Table[], as explained by this post. ...
35 views

Example: ...
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Convert between string and expression representation of boxes

Boxes may be represented as expressions or as strings. How can I convert between the two forms? In particular, how can I convert from the string representation to the expression representation? ...
2k views

How to find the name of the current function?

I would like to know the name of the current function from within that function. For example, consider the following code ...
3k views

Mathematica Destructuring

Context I'm writing a function that look something like: ...
365 views

Why does array packing in Table behave like this?

Consider the following example, which generate two identical arrays. Why sometimes the array is packed and sometimes it doesn't? And why they perform differently? Here the arrays are packed: ...
241 views

Put local variables for Block in a variable

Is is possible to assign {x = 2, y = 3, z = 4} to a variable var so that one can write ...
2k views

What is the complete list of valid FrontEnd Packet types?

In response to my question How can I get the unchanged Box form of an arbitrary expression? John Fultz answered with a method using the hilariously named ...
392 views

Setting options of expressions similar to using SetOptions on objects

Introduction I often have the problem that in an expression, I want to change an option. If we are sure the option is not present, we could simply use ...
84 views

Function of a function, both of a list of variables

I am trying to avoid dealing with long explicit lists of variables. What i do so far is the following: VarList={x_, y_}; ParList={x, y}; ValList={2, 3}; What ...
320 views

How to take a part from a list without evaluating it

Consider I have a list l ...
4k views

How to create symbols from strings and set values for them?

I am trying to convert a list of string names into symbols, which will then be used to store data. I have 24 files (where the name of each file is a member of the list mentioned above) that I need to ...
145k views

Where can I find examples of good Mathematica programming practice?

I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ...
9k views

How to plot periodic function's graphic?

How to plot periodic function's graphic? For example, $f(t) = t$ when $-5<t<5$ and $f(t+10) = f(t)$. ...
503 views

Why can't I inject expressions in Compile using (only) With

Generally speaking, With can be used to inject into arbitrarily held expressions, for example: ...
2k views

Splicing a list of arguments into a function with Sequence

Not sure if this has been asked, but I have a fairly simple operation that I don't know the syntax for. Say I have an array with some values, and a function f that accepts an arbitrary number of ...
199 views

Operations on expressions within Hold

I want to convert {Hold[1 + 2], Hold[3 + 4], Hold[5*6]} into Hold[{1 + 2, 3 + 4, 5*6}]. I have tried ...
150 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 ...
1k views

How to inject an evaluated expression into a held expression? [duplicate]

I know that there are methods to structurally manipulate held expressions (discussed e.g. here), but I failed to apply those for this particular problem: ...
4k views

Function in Table

I need a table with the elements made of pure functions and list elements. This is a simplified example: I need a list as: ...
7k views

How to completely delete the head of a function expression

Is there any way to completely remove the head of an expression function? For example, how would I remove the head Cos from ...
113 views

How to get LogPlot to accept a Sequence for its Min/Max Limits [duplicate]

If you use Plot like this, Plot[Sin[x], {x, 1, 5}] it produces the correct Sin graph ...
190 views

How can I use sequence in plotting domain?

I would like to plot a function but have a domain defined elsewhere as follows: xrange = Sequence[0, 2π]; Plot[Sin[x], {x, xrange}] However, this doesn't work ...
917 views

Generating assignments and transforming code inside held forms when generating code

I have been playing with slightly above trivial code manipulations in Mathematica. I thought Mathematica would be great for this kind of work because of rule replacement and expression manipulation, ...
325 views

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 ...
180 views

Syntactic Sugar for TestReports

Seems to me that VerificationTests are a bit verbose: ...
844 views

How to properly inject iterators into table? [duplicate]

Goofing off on a prior question, I was fiddling with other methods, which led me to the need to inject a constructed set of iterators into a table construct. Now, ...
295 views

different situations with Compilation of ConstantArray

First, we load some tools related to Compile for analysis. ...
161 views

Overriding the behavior of Dot

I would like to override the behavior of Dot, so that Dot[u,v] will return a scalar instead of a 1x1 matrix in the case that the ...
1k views

How to replace a variable that was assigned a value before

Question How to make the replacement $f[x] \to f[y]$ for an abitrary function $f$ if $x$ was assigned a value before? Example 1 How can I make the replacement $x +1 \to y + 1$ if I have assigned ...
8k 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 ...
9k views

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 ...
1k views

How to evaluate some parts of an expression inside Hold? [duplicate]

I want to return a Hold expression but with some parts pre-evaluated. The easiest way to explain this is probably through code example. Here is what I have ...
95 views

Writing a procedure that invokes Manipulate[]

I would like to write a procedure with the signature: Foo[vars, params] which produces a Manipulate object. The procedure ...
153 views

Generating compiled functions from inactive expressions

I am working on a project in which I need to dynamically generate CompiledFunctions from Inactive expressions. For example, I ...
799 views

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 ...
828 views

How can I change a list to a sequence without destroying nested list

I defined a function f like f[x___, y_] := something; and if xs and ...
204 views

Order of Evaluate for Map

I would like to get a list of variable names as strings. For example, x = 1; y = 2; Map[SymbolName, Unevaluated /@ Unevaluated@{x, y}] {"x", "y"} This works ...
2k views

Local variables

I'm trying to use Modules together with functions. tmp2 = x^2 + 1; f[y_] := Module[{x = 1}, Evaluate[y tmp2]] This works when ...
1k views

Displaying a series obtained by evaluating a Taylor series

Description of problem I would like to use Mathematica to display the series obtained by substituting a value for $x$ in a Taylor series expansion. The terms of the series will be rational numbers, ...
887 views

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 ...
390 views

Evaluation in lambda function

If I have a function, that returns a function, for example: f[a_] := a^2 * # & then f[3] == 3^2 # & Is there a way ...
3k views

Define function using variable list

I have a list of variables variables={a,b} and a list with values values={1,2}. I'd like to define a function using the ...
539 views

Generate regularly spaced points from the surface of simplexes

I need to generate regularly spaced samples (points) from the surface of unit simplexes with 2 or greater vertices or end points. I can generate random samples pretty straightforwardly: ...
156 views

Using a variable to tell Mathematica which existing variable to manipulate

I have an estimation routine I have coded up, I want now to do some tests on it where I pick a particular parameter and run the estimation for differing values of that parameter. What I want is to be ...
1k views

Dynamic Programming with delayed evaluation

By using dynamical programming, we can save intermediate steps for recursive relations, as in f[n_]:= f[n] = f[n-1] + f[n-2] However, this only stores ...
185 views

Using sublists returned from a function as elements of a list argument to an other function

This is a contrived example, but it gets the point across. I am looking to use the following as inputs: ...