481 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 ...
760 views

### How can I ensure that I am constructing patterns in the most efficient way possible?

Inspired by this answer, I am interested to know if there are best practices or rules of thumb for constructing patterns, for example for use in function definitions (...
340 views

### Searching linked lists that contain lists?

Following the advice I've read here and other sites, I've been trying to use the Mathematica equivalent of a linked lists... ...
755 views

### Partitioning a list by recursion (Programming Paradigms via Mathematica (A First Course))

I am working through the course Programming Paradigms via Mathematica. One of the homework exercises for the section Recursion I: Passing the Buck is as follows: Use recursion to partition a list: ...
2k views

### Count consecutive positions with the same value

I want to program a function that counts the successive positions with the same value: In[]= ConsecutiveValues[{1, 1, 1, 1, 2, 2, 1, 0}] Out[]= {4, 2, 1, 1} In ...
1k views

### Built-in Mathematica data: are they cached? how to speed up the loading?

Mathematica has numerous built-in data for science and math. Every first call to a data function in a new Mathematica session will "re-initialize indices" (download the data). Is there a way to store ...
526 views

### Find positions of duplicates that are neighbours

Assuming the following list {1,2,3,3,5,6,3} I would like to get the position of values that are next to each other and are duplicates. That is, the output should be {3,4}. Thank you for any help. ...
461 views

### Remove element from list and store it in variable?

In many programming languages there are functions that remove an element from a set while giving back that element. E.g. I'd like to have a function FetchFromStack ...
766 views

### How to memoize a function with Options?

Consider the following modified fibonacci function: ...
2k views

### Simpler way to fill date gaps with zero values

One basic problem when working with data like sales and dates is the case where you don't have sales in all days, so you have to fill it to take information as average or to make a plot. See this toy ...
416 views

### Generate PrimePower counting function

Is there a way to generate a counting function for prime powers - i.e. to create a similar function to PrimePi, but including prime powers. The following will, of ...
818 views

### What are some useful (or hidden) properties of MeshRegion?

There is quite a bit of powerful functionality built in to MeshRegion, but it seems to be lacking in some areas. For example: extracting a list of edges that live ...
746 views

### How to draw the image of a circle under the action of a transformation of the phase flow?

How to draw the image of a circle $x^2+(y-1)^2<1/4$ under the action of a transformation of the phase flow for the equation $\dot{x}=y,\ \dot{y}=-\sin x$? Here $\dot{x}$ means $dx/dt$. Any help or ...