11 questions linked to/from Orderless pattern matching
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### 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): ...
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 ...
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: ...
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 ...
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: ...
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### 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 ...
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 ...
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### Why rule does not work if Flat attribute?

The following works: ...
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### 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): ...