MaplePrimes - Questions and Posts tagged with list

plotsetup and if statements

ce5 — Fri, 18 May 2012 13:48:08 Z

Hello

I have Problem with the Maple command plotsetup, it does not seem to work within an if-statement.

What i would like to do is this:

1. Make a matrix with 0 or 1 as enteries

2. convert this matrix into a list where the 1's are points. (So the Matrix entery Matrix[1][1]:=1 would give the listvector:=[1,1]

3. plot these vectors as graphs and store them with the help of plotsetup

4. changing the matrix and rinse and repet 2,3,4 until satisfied

Testing for a complex number

Ronan — Sun, 06 May 2012 22:05:44 Z

I need to test a list of numbers to find if any of them are complex. if a complex is found then remove that complete row from the list. the potential complex numbers in my list are a, b and c. b is complex i.e has a non zero imaginery part in row 1 so only row 1 should get deleted. the a b and c were originally generated from the arcsin function. Would appreciate help on this. I know it should be simple enough to do. Thanks in advance.

Vector of lists: how to extract list elements?

Mac Dude — Sun, 06 May 2012 01:07:40 Z

I have a column vector of lists. FWIW, it was generated by numerically solving an ODE and then map-ping the solution over a vector with values for the independent variable, like "yt:=map(solnn,xv)" where xv is a column vector with floats and solnn is the result of a dsolve(...,numeric). Each element of the solution vector yt has the form [t=..., y(t)=..., d/dt(y(t))=...] and has the type List.

I want to extract the solutions for y(t) (i.e. the numbers only) into a new...

How can I count the repeating number of some certain expression in a list?

rhenskyyy — Mon, 23 Apr 2012 11:20:20 Z

For example, in the list [1,1,1,1,2,4,6,1,9], how many 1s are there?

Is there a procedure in Maple? Or how can I manage to do it?

A PALINDROME LIST

asghar — Tue, 10 Apr 2012 05:19:47 Z

I need to make a procdeure which checks whether a list L is a palindrome or not. Any help would be appreciated.

Mystery using lists in solve

Alan Mehlenbacher — Sat, 07 Apr 2012 23:27:47 Z

Up until now, I have been using lists instead of sets in solve() in order to ensure the first equation is solved for the first variable, the second for the second, etc. However, I have run into a case for which using an equation list and a variable list does not work, but the equation list alone is fine, and sets of both are fine, etc. I would be grateful if somebody can explain why the first statement below does not produce a solution.

> soln := solve([foc1 = 0, foc2 = 0, foc3 = 0...

Index of min/max value of vector/list/...

Jarekkk — Tue, 03 Apr 2012 21:05:17 Z

I need this quite often, but never found a nice way of getting the index of minimal or maximal value of a Vector (or a list or whatever). Is there an easier way than the following?

N := 15:
L := LinearAlgebra[RandomVector](N):
m := min(L):
for i to N do if L[i] = m then print(i); break end if end do;

Function from numbers

ABond — Tue, 07 Feb 2012 17:00:00 Z

Hi everyone,

I am trying to build a function of dsolve/numeric solution which would not include procedures for defining the value of it.

First, I need to extract solution as a 2-d array, which will contain all evaluated points of solution.

Next, I want to define a function from this set of points (like interpolation).

Say, I have an array or list of numbers (2-d points).

Now comes the main question: is there a way to interpolate some...

Operating on a list of values with units

erik10 — Mon, 06 Feb 2012 01:38:07 Z

Dear Maple users

The formula f = c/λ is expressing the frequency in terms of the velocity of light c and the wavelength λ. Lets say given not just one wavelength, but a whole list af wavelengths. The values have units attached. I wonder if there is an elegant way to have Maple calculate the all the frequencies, eventually delivering them in a new list?

I want the units of the output reduced to SI-units,...

How to find the minimum plus-minus ?

Markiyan Hirnyk — Fri, 20 Jan 2012 14:47:22 Z

Let a list of n positive integers be given, e. g. [2,1,4].
Let us consider all sums of all its members signed by +-, e. g
-2-1-4=-7, -2+1-4=-5, -2-1+4=1, ... .
How to find the sum having the minimum absolute value with Maple?

writedata (on a single line)

Carlo Carminati — Thu, 12 Jan 2012 08:59:23 Z

have a list of lists, and I would like to write each of these lists on a separate file, *on a single line*.

For instance consider the following trivial example:

P := [[-.3819660120, .6180339880, -10000, -2], [.6180339880, 1.618033988, -10000, -1], [1.618033988, 10000, -10000, -.5], [2.618033988, 10000, -.5, -0.1e-3], [2.618033988, 10000, 0.1e-3, .5]]

I would like to create
+ a file named P1.dat containing the line
...

How to convert a list name to string

protrader — Sun, 27 Nov 2011 07:58:52 Z

I have a procedure that gets two lists A and B, I want to restore the name of the entry lists as string. How can I do that?

f(A,B) [procedure]

e.g. a(MyList,LL)

I want to restore a:="MyList" and b="LL"

TIA

A little problem

Fei Wang — Tue, 15 Nov 2011 12:13:49 Z

When using the command "for", the results are placed in a column,such as if we input
for i from 1 to 3 do i end do, the results are showed as

This style is not convient to use for following computation. So how to put all results into a list or set ?

remove commas from a list

louisewatts — Sun, 13 Nov 2011 09:30:55 Z

Hi i'm new to maple.

Is there a way to remove commas from a list?

I was able to remove the list from its brackets []
but i was wondering if I'm able to remove the commas also?

How to get a list of power of differential function expression

Fei Wang — Thu, 10 Nov 2011 03:59:36 Z

Giving a expression as follows, how to extract powers of g to a list?

In this example the list of powers of g is {2,1,2}