Linked Questions

3
votes
0answers
77 views

How to match the arguments of the function in any order [duplicate]

The issue is the following, with a dumb function with (4) arguments of (4) different heads (for each head is always no grater than one arguments): ...
533
votes
19answers
133k 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 ...
34
votes
9answers
3k views

How to select minimal subsets?

I am a newbie, so please point me in the right direction if you feel this question has been answered somewhere else before. Here goes: Suppose I have a list like this: ...
30
votes
7answers
3k views

How to Derive Tuples Without Replacement

Given a couple of lists like a={1,2,3,4,6} and b={2,3,4,6,9} I can use the built-in Mathematica symbol ...
20
votes
2answers
631 views

SetAttributes[f,Flat]: Why the order dependence?

I'm experiencing a strange phenomenon. Here's a (quite artificial) test case: The following definition work just fine: ...
9
votes
4answers
448 views

Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a

I want to have a function (called otimes) with the following two properties: it has the attribute OneIdentity and ...
5
votes
2answers
147 views

Convert String to Integer from a huge string database in a very fast way?

I have a huge string database with the form such as {{position},{1,2,3,4,5,..}}, and I want to convert such database to Interger data in a very quick way. In the following example, I created a ...
6
votes
2answers
303 views

Why rule does not work if Flat attribute?

The following works: ...
1
vote
1answer
925 views

Why does Mathematica add Hold to the result of my user defined symbol?

In the code below I have defined a symbol that multiplies two block-matrices (I can't use the builtin Dot since Dot assumes that the matrix coefficients commute): ...
4
votes
1answer
81 views

Subtle order-of-evaluation issues when pattern-matching with attributes

Related question concerning unrolling the tests that are shown below: Big and Little surprises when unrolling tests of pattern-matching and attributes Questions researched before posting this one: ...
3
votes
1answer
78 views

Big and Little surprises when unrolling tests of pattern-matching and attributes

Related question concerning interpretation of the substitutions: Subtle order-of-evaluation issues when pattern-matching with attributes Questions researched before posting this one: Orderless ...