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3
votes
2answers
102 views

MapThread problem

I would like to do the following: ...
2
votes
0answers
56 views

Unexpected behavior from Indexed

I was going to include Indexed in this answer, thinking that it operated much as a List-only ...
0
votes
1answer
58 views

What does this Append expression do? [closed]

I have to understand some code. A part of it is written below. Can someone explain to me what it does: ...
9
votes
6answers
369 views

Product of elements of a list

Sum is for functions; Total is for a list. Product is for a function; what is the command ...
9
votes
2answers
121 views

DownValue assignment using Apply

Why does assigning a DownValue using Apply, e.g., ...
2
votes
0answers
30 views

How exactly does ReplaceAll work? [duplicate]

I am not sure if this question has been asked before but anyway, Consider these two examples: ...
5
votes
4answers
186 views

Signed power set of a list

Given {a, b, c, ...} with $n$ elements generate a list with $2^n$ elements. For example, if the list were {a, b, c}, then the ...
0
votes
0answers
86 views

Solution of a set of quadratic congruences (Chinese remainder)

Edit: Please remove this question. I think there are mathematics error in what I am asking. You are welcome to edit the question if you can state the problem correctly. I have a set of quadratic ...
2
votes
1answer
260 views

Dynamic graph construction and visualization (Watts' “Small Worlds” α-model)

I need some help in creating a Mathematica program for building and visualizing Watts' "Small Worlds" α-model. This is a variant of the more known (and much more simple) β-model (also known as ...
5
votes
2answers
141 views

Non sequitur in documentation of MemberQ

Mr.Wizard's question about MemberQ and FreeQ got me to re-read the documentation for those functions. I find I don't understand ...
0
votes
1answer
64 views

Association of pure functions [duplicate]

I've encountered confusing behavior of Association when I try to use it for storing pure functions. For example: as = <|"1" -> # + 1 &|> ...
9
votes
5answers
414 views

Postfix Double Slash Notation with Multiple Parameters [duplicate]

Examples A convenient shorthand that I use frequently is the "double slash" notation to string commands together. For example, I can write: ...
11
votes
2answers
208 views

How to restore function attributes to default

Adding an attribute to a function is easy and clearing attribute is easy also. But I don't know really how to restore the attributes of a function to its defaults. All I do is quit the kernel or close ...
3
votes
1answer
277 views

How to use Mathematica for traditional programming

I am new to the structure of Mathematica. I understand that in the notebooks, one enters the symbolic expressions and evaluates them. But I need to generate some simulated data and do that a few ...
34
votes
2answers
862 views

Why is the new PositionIndex horribly slow?

This issue has largely been mitigated in 10.0.1. New timings for the final test below are: ...
7
votes
1answer
201 views

Why can't a string be formed by head String?

Since everything is an expression in Mathematica, why must a string object be formed by "abc" but not by a String[abc] ...
2
votes
3answers
133 views

How to test for Indeterminate values?

I need something like this a = 101010/0; If[a == ComplexInfinity, True, False] But if I use ToString, I get what I want. ...
6
votes
1answer
127 views

Taking the derivative of a function with indexed variables

I have a number of functions that depend on a variable x. I am using a second, integer variable to index these functions, i.e. something like ...
1
vote
1answer
39 views

Strange behaviour of Set and Part when given a sequence

Consider this example: lis1 = {a, b, c}; lis1[[2]] = Sequence[e, f]; lis1 (*{a, e, f, c}*) lis1[[2]] (*e*) lis1[[2]] = Sequence[g, h]; lis1 (*{a, g, h, c}*) It ...
4
votes
1answer
88 views

How to define a formula in FormulaData?

I am looking for a way to manage frequently used formulas in my research, in a organized way in Mathematica. It appears to me that using FormulaData would be a ...
7
votes
6answers
435 views

How to build a list of functions

Having said that I'm no expert, I have some problems in generating a list of functions inside a loop. The functions in the list should depend on the elements of a parameters list, that are read in ...
1
vote
1answer
62 views

Why does WordData fail to find “PartsOfSpeech” when given a list of two words?

I have the following sample code. StringSplit["a test string", " "] Thread[WordData[%, "PartsOfSpeech"]] The output I get is: ...
4
votes
1answer
188 views

How to see abstract syntax tree of Wolfram Language expression

I mean, suppose I have this expression: 2 + 2 I want to get something like this: Plus[2, 2] as an output. I've tried FullForm, but this just evaluates 2+2 and returns 4. Is this even possible?
22
votes
2answers
466 views

Why is Query so much slower than Part?

Time for another of these(1),(2) as yet another new-in-10 function appears to have poor performance compared to older alternatives. This time: Query appears to be ...
10
votes
0answers
286 views

Create a new infix operator [duplicate]

It is well known that the infix operator @@ is used as a short form of Apply. For example, both ...
6
votes
2answers
201 views

Why does Mathematica appear to change the head of certain expressions?

I don't know if the question trivial or not (if so I will delete it), but here is what I have: I know that x x (* x^2 *) Looking at the full form gives ...
14
votes
2answers
305 views

Can't get Append to append a record (association) to a dataset

The Documentation Center item, Computation with Structured Datasets, implies that Append has been extended in V10 to work with datasets. But not on my computer. (I ...
0
votes
1answer
113 views

Need help in understanding code [closed]

I am just beginning with Mathematica. I have received this code to study. I am not able to follow this particular section. I have tried looking it up on many forums, with no answer. Can you help? ...
3
votes
0answers
377 views

Is Wolfram Language suitable for building web applications? [closed]

My goal is to find a technology which will afford me to build web applications (e.g. simple social networking site) as quickly as possible (with as little code as possible). I was impressed by Stephen ...
4
votes
1answer
138 views

Multiple down-values with exactly the same lefthand side

I was working on an answer to this question, when I was sidetracked by what I bring up here. I wanted a function, which when given a string representing a binary number, would convert the string to a ...
2
votes
1answer
46 views

Is the use of Block to temporarily override definitions inherently unsafe? [duplicate]

This may have been discussed before, if so, please let me know. Consider the following example: x = 5 Dynamic[{Clock[], x}] This will always display the ...
1
vote
1answer
86 views

Why is Return not forcing an exit from my function? [duplicate]

Here is simplified version of my code that exhibits the behavior troubling me: ...
8
votes
3answers
688 views

Why are functions called first-class objects in Mathematica?

I've heard lots of people say a function is a first-class object in Mathematica. "Everything is an expression, including function." "There is no distinction between functions and data." Having read ...
7
votes
3answers
272 views

Implementing key-value associations in Mathematica 9 with inexact numbers for keys

I'm not sure of what type of problem my issue falls into, so I haven't been able to search forums with any success. If this has already been solved then my apologies! Essentially I'm trying to set a ...
1
vote
2answers
138 views

Unexpected Plot3D behaviour

The following illustrates what appears to be an incorrect Plot3D for this polynomial. I have forced the function to complex argument, changed ranges. In contrast, ...
0
votes
3answers
123 views

Identifying the symbol which has a specific value

I'm writing a program that will solve the value of 1 variable in a 4-variable equality equation, but the variable to be solved will depend on the user's input to the program. This is what I've come ...
4
votes
2answers
156 views

Solve a system of M equations without specifying M

This post has been edited heavily in response to the comments: my initial question was very confusing. I am trying to write my game-theoretic model in Wolfram Language. There is only one remaining ...
2
votes
2answers
103 views

What is wrong with my use of Flatten? [closed]

Why does Flatten[f[g[a, f[b]], f[c, d]]] result in f[g[a, f[b]], c, d] I expected the answer to be ...
2
votes
1answer
246 views

Euler's method for a 2nd order ODE

This is my first post on this site. Also, I'm new to Mathematica. I'm trying to solve my first problem with Mathematica. It's about solving a 2nd order differential equation. I dont have the explicit ...
2
votes
1answer
90 views

Can a Symbol own OwnValues that don't evaluate when it's the head of an expression?

I believe this a question that most of us have encountered when we were beginners but forgot when we got more familiar with Mathematica. We know the notation $y=y(x)$ for functions, where $y$ here ...
47
votes
3answers
3k views

Is Mathematica an Implementation of the Wolfram Language?

I am trying to figure out what the announcement of the Wolfram Language means for Mathematica. Is Mathematica an implementation of the Wolfram Language, or is it something else?
0
votes
0answers
79 views

Using Wolfram Language without Raspberry Pi [duplicate]

What are the different ways I can start using Wolfram Language even though I dont want to use Raspberry Pi? Are there any convenient ways? I actually have a raspberry pi but I am trying to find ...
3
votes
4answers
597 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 ...
0
votes
0answers
57 views

?function-name does not return function help

For some reason when I use ?function-name to ask for help on a function, I got a very clinical breakdown of that function with its options and attributes instead of the blurb about the function: To ...
4
votes
1answer
101 views

How can I extract all the non-number symbols from an expression [duplicate]

If I have an expression, let us say something like this: Cos[3 x] + π/cofe Exp[y^(c z)] how can I get all non-number symbols in the expression which are: ...
0
votes
0answers
34 views

Unexpected results from Thread [duplicate]

I've run into an issue where threading two lists with a generic function, f: Thread[f[{{1,1}, {2, 2}, {3, 3}}, {4, 5, 6}]] ...
7
votes
1answer
305 views

Find a word's linguistic pronunciation

Is there a way to get a word's linguistic pronunciation given the word as a string? I would like a function LingusticPronunciation such that, for example, ...
4
votes
2answers
206 views

How can I avoid getting the error message Goto::nolabel in my code?

If anyone could suggest a reason why Label[begin] ... Goto[begin] would return Hold[Goto[Begin]], and (better) how can I avoid ...