Linked Questions

11
votes
4answers
5k views

Plot columns of table if some condition is fulfilled

I have a table with data, for example MT = {{1, 80.3, 1, 4, 68}, {2, 80.5, 1, 5.5, 102}, {3, 80.0, 0, 4.2, 78}, {4, 80.4, 0, 3, 17}, {5, 80.2, 1, 5, 180}}; ...
29
votes
1answer
711 views

Why doesn't PatternTest work with Composition?

While playing around with the solutions to this question, I've found some very strange behaviour: ...
13
votes
2answers
1k views

Displaying a series obtained by evaluating a Taylor series

Description of problem I would like to use Mathematica to display the series obtained by substituting a value for $x$ in a Taylor series expansion. The terms of the series will be rational numbers, ...
5
votes
5answers
1k views

How can I use nested conditionals inside my functions?

I'm a big fan of using conditionals inside my functions to deal with cases, that is, to pattern match in stages and possibly leave a function unevaluated. ...
7
votes
2answers
928 views

Position function not always returning an answer even with no apparent problems

I'm having some problems with Position. Sometimes it will give an empty list instead of the actual position of the element I am looking for when that element is ...
6
votes
2answers
4k views

How to restrict the domain of a function

I realize this question has been asked many times, but I am fairly new at Mathematica and the other answers are very complex, and certainly too complicated for this simple code I am trying to write. ...
4
votes
3answers
581 views

Simplifying expression with patterns (Replace)

Q1: I need to simplify some algebraic expression, according to particular pattern, namely: \begin{equation*} x^m = \left\{ \begin{array}{ll} 1 & \text{if } m \text{ is even} \\ x & \text{if }...
6
votes
2answers
233 views

Why the pattern match don't work as expected

When I try to figure out this problem,I write such code: ...
0
votes
2answers
2k views

Function with condition

I am starting my adventure with Mathematica. I would like to know if is there possibility to create function described by formula for example f(x):=1+2^n where 2^n < x. I have problem with this ...
6
votes
1answer
1k views

Evaluating function only when its optional argument is numeric

I want to have the argument 'a' for myf2 in form of optional argument, but at the same time I need to evaluate the function only if 'a' is Numeric, see also my previous question. ...
4
votes
2answers
645 views

Pattern test for variables during function definition

I am having a problem with pattern testing on variables during function definition ...
8
votes
1answer
482 views

Why does pattern test work only with pure functions?

Why is it that pattern test works only with pure functions? Cases[Range[0, 70], _?(Divisible[#, 7] &)] Cases[Range[0, 70], x_?(Divisible[x, 7])] I ...
1
vote
3answers
278 views

IntegerQ returning False despite setting Assumptions

Why does the following not return True? Assuming[z ∈ Integers, IntegerQ[z]] False I tried this on a fresh session of ...
5
votes
1answer
436 views

Use of StringExpression as argument

Is it possible to use a StringExpression as a pattern for an argument? I.E. something like foo[chars__~~ WordCharacter.. ~~ num:NumberString] := {chars, num}; At ...
5
votes
1answer
415 views

Convert boolean test function to pattern?

What is a "reverse" to MatchQ? MatchQ converts pattern into boolean function. So how to convert back? Suppose I want to use ...

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