Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.

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0
votes
2answers
156 views

Convert *.txt file

I would like to Import and Convert a *.txt file which looks like: https://docs.google.com/file/d/0Bw-308nJcF01Yl92RURCLUg4VzQ/edit?usp=sharing and turn it into a Matrix which I can use to make ...
22
votes
4answers
5k views

Finding Local Minima / Maxima in Noisy Data

I'm trying to find local minima / maxima in noisy data, consisting of data values taken at certain time intervals. Ideally, the function should take a pair of lists (one containing time values and one ...
1
vote
3answers
183 views

How can I create a new tables out of a table and plot it

I have the following problem. I have a table, call it m, which is labelled by 3 indices (say i,j,k), each of them running from 1 up to 100. I would like to be able to construct a new table which would ...
5
votes
1answer
499 views

nested use of Apply/Map/MapThread in pure functions

1. My main question I have a function with two argument slots. I wan't to apply this function to 2 lists with different length's. I thought in this solution: ...
5
votes
5answers
2k views

How to sum over a List

list = {11.5575, 11.397, 5.52734, 4.0878, 2.54815, 1.86652, 2.55028, 2.14952, 1.6242, 1.34117} I have a list of numbers. How do I make a function that creates a ...
1
vote
1answer
153 views

ReplacePart inside For loop

I am trying to replace the last column of the following expression (mat) by doing ...
2
votes
1answer
147 views

Plot several lines with different starting points on the x-axis

First of all, I would like to apologize in advance if I don't use the correct terms or if I express myself unclear but I just started to work with Mathematica. I'm simulating electricity prices and ...
17
votes
7answers
1k views

Find continuous sequences inside a list

I have a list which is something like this: {3,4,5,6,7,10,11,12,15,16,17,19,20,21,22,23,24,42,43,44,45,46} What I'd like to to is get the intervals which are in ...
0
votes
1answer
504 views

Keeping axes fixed in an Animate of a 3D graphic

I am using the following code to animate a 20 3D ListPointPlots: ...
6
votes
2answers
343 views

How can I find if the number of subsets for a list is very large?

I'm trying to find the following; Subsets[Range[2, 2300], {4}] but my computer gave the following error: ...
27
votes
1answer
529 views

How can I make threading more flexible?

Threading automatically with Listable functions requires the argument expressions to have the same length (or for one of them to be atomic). For nested lists the ...
3
votes
3answers
239 views

Logical AND operation over several comparisons

Let x and y be arrays defined as Array[x, m], Array[y,n] respectively. How to generate the following function of $x$ and $y$ for variable $k$: ...
3
votes
1answer
273 views

Including two ListLinePlots in a 3D graphic

I have two lists of data which I am plotting on two ListLinePlots. I would like to have these two plots appear perpendicular to each other on a 3D graphic. I have ...
-4
votes
4answers
157 views

Extracting the integers from a list

I have a list where the elements are Reals and Integers. How can I extract the Integer? For example, if I have {1, 2, 3.4, 9.9}, how can I get ...
1
vote
3answers
383 views

Summation over 3 lists

I have three lists. As an example, a = {10, 5, 6, 8, 7}; b = {4, 8, 9, 7, 9}; c = {7, 5, 12, 4, 1}; I want to get $$x(i)=\sum ...
0
votes
0answers
29 views

Error in extracting a column [duplicate]

I imported excel data to Mathematica using this command. kuruzD = Import[ "C:\\Users\\TMH\\Documents\\Problem Set 4\\kuruzData.xlsx"][[1]] //TableForm I want to ...
1
vote
3answers
377 views

How to find intersection of multiple lists excluding empty ones?

I have lists like list1={1, 1, 2, 3}; list2={3, 1, 4}; list3={}; I want to find the intersection of all list. I tried the following way, but it's not working. ...
1
vote
2answers
229 views

What ways are there to convert an Integer to a list of digits?

How can I convert an Integer to list of numbers? For example: 781049 ==> {7, 8, 1, 0, 4, 9} What are the possible ways of ...
2
votes
2answers
262 views

Efficient code for building a big list

I would like replace the following code ...
0
votes
1answer
310 views

DataRange problem in a ListLinePlot within a Manipulate

I'm trying to create a simulation of a set of lists with Manipulate[] and ListLinePlot[]. However, as my simulation starts with ...
2
votes
5answers
352 views

Creating ordered triplets from an Excel sheet

I have an Excel sheet of the form: " " a b c 1 R S T 2 U V W 3 X Y Z Where every entry is a number (except the blank quotes, ...
0
votes
0answers
53 views

DeleteCases and Inequalities [duplicate]

I would like to remove cases from a list according to an inequality rule - e.g. remove all values less than x. I can do the following but this seems very clumsy: ...
2
votes
2answers
357 views

How to prevent errors in Manipulate with ListPlot when a result is an empty list?

I am trying to plot two lists, where one is the reference list, and the other is only used to select and highlight the first list. Basically, I want to use the selection list ...
4
votes
5answers
1k views

Removing zero values from ordered pairs

I have some processed data, which are basically a collection of ordered pairs in the form: {{x1, y1}, {x2, y2}, ..., {xn, yn}} Ordered pairs which have either a ...
15
votes
6answers
683 views

Matrix Rotation

If I have a matrix of any size, say $\begin{pmatrix} 72 & 32 & 64 \\ 18 & 8 & 16 \\ 63 & 28 & 56 \\ \end{pmatrix}$ $\begin{pmatrix} 72 & 32 \\ 18 & 8 \\ 63 ...
2
votes
3answers
205 views

Speeding up a simple simulation with random extractions

I wonder if anybody can help, I need a hand with a simple simulation I am writing with Mathematica (I am using version 8). Basically it creates a list (called l) with numbers from 1 to n and a random ...
5
votes
2answers
246 views

Better method for creating a tuple out of two lists

I just combined two lists using this method ...
1
vote
2answers
82 views

How to construct a new list made from a function that operates on two lists

I need to take two lists (each list contains the number of moles of a chemical). I have a function calledFraction that takes the each entry of the list and then calculates the mole fraction of ...
2
votes
2answers
287 views

List of numbers without common factors with a certain number

Is there any function in Mathematica which directly gives an array of integer numbers with no common factor with a certain integer number? For example, all the integer numbers between 0 and 1728, ...
-1
votes
2answers
689 views

Convenient methods to sum select rows (or cols) of a matrix? [duplicate]

What are some convenient methods to sum selected rows or columns in a matrix? This question Summing along rows or columns of a matrix only addresses how to sun entire rows or columns ie, by level. ...
5
votes
1answer
194 views

Trouble with Flatten[]

I made this function: f[g_] := Table[{ToExpression[ToString[x] <> ToString[n]], 1, 3}, {n, 1, g}] When I evaluate the function with some g (say 8), I'll ...
1
vote
2answers
252 views

How to blend some colors on a curve

I need to define a color gradient on a 3D curve, but I'm having some problems with this. Suppose we have a 3D curve defined as a parametric function of some real variable ...
19
votes
4answers
760 views

Accessing list elements by name

First, a bit of a long introduction to my problem: I only have a few weeks of Mathematica experience. I am creating a mathematica application that calculates some material properties of steel based ...
5
votes
1answer
177 views

Can the elements of a list always be sorted into a canonical order?

As the title states - does a unique order exist for any Mathematica list to be sorted by the Sort[] function (or as returned by a function that treats lists as ...
4
votes
1answer
173 views

How do I group a nested list further according to a rule, and average selected elements?

I have a nested list of numbers like { {36, -244}, {37, -225}, {38, -197}, {48, -200}, {49, -181}, {50, -133} } which needs to be further nested into "bins" according to a rule. I would describe the ...
11
votes
3answers
527 views

How to add lists with unequal length?

Given lists of unequal lengths, I want to add them together element-wise, treating missing elements as zero. For example, {1, 2, 3} + {a, b} + {x} should give ...
3
votes
2answers
141 views

Creating a list from other lists and varying the number of elements that get added

Suppose I have listA = {M, F} and ListB = {a,b,c} I want to make a new ...
0
votes
1answer
119 views

How to extract data from a list? [duplicate]

I have a long list of coordinates defined in some 8D space. I need to extract the first three coordinates only. How ? For example : ...
4
votes
2answers
377 views

List reversion inspired by Python

In python, if you wish to reverse a list, here is the trick: range(10)[::-1] => [9, 8, 7, 6, 5, 4, 3, 2, 1, 0] Note: ...
3
votes
1answer
208 views

How to store values indexed by integer partitions for fast access?

I have a huge list of values indexed by integer partitions. If I store them simply in a list, then, when I want to access the value corresponding to some particular integer partition, I have to find ...
-5
votes
5answers
523 views

Translating MATLAB's cell2mat into Mathematica

How I can define a function in Mathematica such that it acts same as the cell2mat command in MATLAB? Example (in MATLAB): ...
1
vote
2answers
762 views

How do I divide the columns of a matrix by the sum of its elements?

I am trying to create a transition matrix for a network. In order to do this, I need to sum down the column (the out degree), and then divide the column by the out degree in order to normalize it. ...
0
votes
2answers
150 views

ListPlot of lists with specified x coordinate

I want to do: ListPlot[{{x1, y1}, {x2, y2}, ...}] each y being not a number but a list of numbers. I tried: ...
4
votes
2answers
252 views

Sorting a matrix alphanumerically

Somewhat related to Sort matrix by columns and rows without changing them, but more general. I'd like to sort a square matrix (a 3 by 3 in my case, but surely the general solution will treat any), ...
4
votes
4answers
259 views

How can I name “a[[i]]” the parts of Table “a”? Or how to make Table “a” grow inside FindMinimum?

Let's say I want to minimize a function that uses a Table named a with the Conjugate Gradient Method of ...
3
votes
2answers
767 views

Adding and subtracting from elements in a list

I'm trying to solve an aparently simple problem. Given a list of length n, {a1,b1,c1,d1...} I want to perform two simple ...
8
votes
4answers
149 views

Mark selected sub-lists in the list they were selected from

I've got this simple problem with two lists. I select some items from a list, but I want to visualize the difference between the previous list and the list that I create with ...
11
votes
5answers
830 views

Building a continued fraction

I've completed a problem that involves approximating $e$ by a continued fraction: $$\frac{N_1}{D_1+\frac{N_2}{D_2+\frac{N_3}{\ddots+\frac{N_k}{D_k}}}}$$ with the $N_i$ being the list ...
4
votes
3answers
397 views

Preparing data for making an ErrorListPlot

I often have the following notebook in Mathematica, which I use to make a dataset and associated errors: ...
2
votes
3answers
503 views

Convert coefficients of polynomials into a matrix

I have several sets of 5 polynomials of the form: ...