Linked Questions

1
vote
2answers
70 views

The difference between ? and /; [duplicate]

I can do the following Cases[Range@10, x_ /; OddQ[x]] But why cannot I do x_?OddQ[x] instead of ...
0
votes
0answers
60 views

How to correctly use PatternTest (?) [duplicate]

This works fine: {3, -5, 2, 7, -6, 3} /. x_ /; x < 0 :> 0 (*{3, 0, 2, 7, 0, 3}*) and this works fine: ...
0
votes
0answers
57 views

Condition in a replacing function [duplicate]

Because of "Thou shalt not copypaste", I'd like to change my pair of replacements F[foo_,foo_+1]:=bar;F[foo_,foo_-1]:=bar; (it's MUCH longer, so it actually ...
553
votes
19answers
139k 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 ...
66
votes
6answers
5k views

How to avoid collision between optional arguments and options

Is it possible to create a function with optional arguments that also takes options? Here is a simple example. I have a function f with option "g". It also has ...
23
votes
8answers
2k views

Selectively Mapping over elements in a List

I am using the following code to easily generate a row of images of all eight planets of our Solar System: ...
38
votes
4answers
3k views

How to create strong types?

In a program I'm writing, I create a list of lists, that looks something like this: {{100, {1,2,3,4,5}}, {105, {2,4,6,8}}, {42, {42,39,56}}} I then pass this ...
18
votes
7answers
5k views

How do I check if any element in a list is positive?

As a simple example of what I would like to do, suppose I have a list a of all real numbers. I would like to perform a simple check to see if some element of ...
39
votes
4answers
4k views

Can a function be made to accept a variable amount of inputs?

I have a function that takes two inputs and processes them for a single output. What I need is one that can take a varying number of inputs. and process them to a single output. Is this possible in ...
40
votes
5answers
1k views

How to examine the structure of Graphics objects

One difficulty I'm encountering in studying the structure of Graphics objects is that I have not yet found a way to print or display such structures that are ...
17
votes
10answers
3k views

Match patterns on list of Strings

Consider the following: data={"AB","CD","AF"}; Now I would like to delete all String from data which starts with "A". Result:...
19
votes
4answers
2k views

Using Position (which requires a pattern) in the same manner as Select (which requires a criterion)

I am using Mathematica7. I have a list of lists (creatively named list in the following sample code) containing data. I would like to find the positions of the ...
13
votes
4answers
920 views

Assessing argument type in set delayed function definitions

I'm wondering how to properly assess the type of arguments passed to functions defined with :=. I want my functions to be the most efficient, unambiguous and clear ...
17
votes
5answers
3k views

Implement the Bisection algorithm elegantly and easily

Description: Rencently, I have finished my course Numerical Analysis, so I'd like to implement many algorithm that I have learned from that course.By this practice, I hope that I can improve my ...
23
votes
3answers
1k views

Quick way to use conditioned patterns when defining multi-argument function?

I have a simple function that is supposed to only accept numeric values (i.e. complex/real numbers and constant symbols e.g. Pi, E). $$f(a,b,c)=a+b+c$$ Edit: I should have chosen a less simple ...

15 30 50 per page