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33
votes
2answers
723 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: ...
4
votes
1answer
456 views

Behavior of expression evaluation in Plot

I'm confused with Mathematica's way of parsing expressions. I've been struggling with this for a while and never found an exhaustive answer, sometimes things don't parse the way I think they would ...
9
votes
2answers
3k views

What does # mean in Mathematica?

I asked Mathematica to compute the following Solve[c (1-x)^2-x^(1/4) == 0, x] and it returned this: x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 ...
16
votes
3answers
316 views

What does None mean in a control specification for Manipulate?

I am now struggling to understand code that contains the following (simplified) Manipulate structure. ...
45
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?
14
votes
1answer
291 views

Shorter syntax for Fold and FoldList?

I find it tedious to write out the following: a = {1, 2, 3, 4}; Fold[f, First @ a, Rest @ a] f[f[f[1, 2], 3], 4] It ...
21
votes
2answers
691 views

Why there is no name for #1@#2&?

Why does the pure function #1@#2& have no name? Is it due to the way Mathematica works, or is it "just because"? I'm asking because I find inelegant to write ...
13
votes
3answers
343 views

Make mathematica treat $e_i^2$ as numeric

With NumericQ[symbol] = True, I can declare that a symbol is numeric. I want the expressions matching: $$e_{\text{i$\_$}?\text{IntegerQ}}^2$$ to be treated as ...
53
votes
3answers
1k views

How to make use of Associations?

I have been curious about it for long. Now that Mathematica 10 arrives, I think it's time to ask the question: How the new Association data structure would be used ...
22
votes
2answers
996 views

Is Mathematica comparable to C++ for creating standalone applications?

At my university, I have a yearly essay. I'm allowed to use any technology for implementing it. I've been coding it in C++ with Qt. I thought of about Wolfram Mathematica because I have some ...
33
votes
1answer
640 views

Incompatible Changes since Mathematica Version 7?

There is documentation of the incompatible changes made to Mathematica with each major release: Incompatible Changes since Mathematica Version 1 Unfortunately that documentation simply stopped ...
21
votes
2answers
446 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 ...
11
votes
2answers
232 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 ...
9
votes
5answers
256 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: ...
14
votes
3answers
168 views

What does `: Hold[$IterationLimit]` mean?

In this answer, what does the : Hold[$IterationLimit] part of the following construct do? ...
18
votes
1answer
472 views

Using Transpose with a list as the second argument

I'm having difficulty understanding the Transpose function. I know what the transpose of a matrix is, not a problem, and I see that applying the ...
8
votes
0answers
78 views

A bug in the overloading of MemberQ and FreeQ for Association?

While answering Pattern match for nested Association I came across behavior of MemberQ and FreeQ in 10.0.1 that I believe is ...
16
votes
1answer
142 views

Help understanding overloading of Atomics within Block

Usually h @@@ {f[1, 2], f[3, 4]} === {h[1, 2], h[3, 4]} but this is not the case when f is ...
10
votes
2answers
169 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 ...
7
votes
1answer
285 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, ...
6
votes
1answer
191 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] ...
4
votes
1answer
113 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 ...
10
votes
1answer
123 views

Why won't SparseArray let me store values with the head List?

When you attempt to define a SparseArray with elements that have the head List it complains: ...
10
votes
0answers
281 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 ...
5
votes
4answers
170 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 ...
5
votes
1answer
155 views

Treat all variables as local in a module [duplicate]

In most languages, any variable defined inside a function is considered local. ...
5
votes
1answer
280 views

Proper use of arbitrary number of variables

So, I'm working on a project where the number of independent variables is not fixed. Consider a problem of $N$ independent variables, $\boldsymbol{r}$. I want to perform different things with them. ...
3
votes
1answer
363 views

Is there the full Wolfram Language in Mathematica?

Today I read the new entry on WolframBlog with all it's nice little demos. I was realy interested in those with astronomic informations, but trying these with my own Mathematica I was irritated: ...
3
votes
2answers
136 views

What is the fastest way to get a list of subexpressions and their positions?

I have spent quite some time trying to figure out what the fastest way is to get a list lists of all subexpressions and their positions. I have tried things with MapIndexed, which seems ideal in cases ...
2
votes
1answer
43 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 ...
2
votes
4answers
366 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
76 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 ...
0
votes
2answers
74 views

How can I make my output to be added to an existing list?

v = {{0, 0, 0}, {1, 0, 0}, {1, 0, 1}, {0, 1, 1}, {1, 1, 1}} For[i = 1, i < 6, i++, For[e = 1, e < 6, e++ 1, Print[Mod[v[[i]] + v[[e]], 2]] ]] I ...