0
votes
0answers
30 views

Not getting proper x-values in a ListPlot [on hold]

I have a table of data points to be subtracted by another table of data points. I have succeeded in subtracting the y values of each data point successfully, but it is the x values of each data point ...
4
votes
3answers
200 views

Element-wise list operation on list of lists

Suppose a function F operates on list A: $$A=\{a_1, a_2,\cdots, a_n\}$$ I have a list of lists, B: $$B=\{A_1, A_2,\cdots,A_m\}$$ Is there a syntax to specify that F should operate on members of B, ...
2
votes
2answers
41 views

Read off entries of UndirectedEdge [on hold]

Suppose I have an undirected edge e=UndirectedEdge[a,b]. How do I extract one of the entries a,b of e? I tried accessing e like a list, but that didn't work (...
8
votes
2answers
139 views

How to partition a list according to a value in the list

I have a list of the form $\{\{d_1,c_1\},\{d_2,c_2\},\ldots,\{d_n,c_n\}\}$. The values c_i take values between $1,\ldots,k$. I want to partition the data into $k$ lists according to the values $c_i$. ...
4
votes
2answers
97 views

Sorting out atom types in an XYZ file

I am trying to rewrite the output of "VertexCoordinates" such that instead of a hybrid list of atoms and coordinates that result from using the following input program, I want all coordinates of the ...
3
votes
3answers
97 views

Working with calculations that depend on the previous value in a list

I'm trying to make calculations on a list that depend on the previous value. In my case I'm doing event detection - detecting the point where a value rises above some threshold for the first time ...
3
votes
2answers
118 views

How to define even permutations correctly?

I define even permutations as following, but there may be some error. I use it in two different way and get different output. ...
3
votes
4answers
150 views

One to Many Lists Merge

I have two lists: ...
2
votes
1answer
50 views

Compare some lists, if elements are almost equal

I've got the solutions of three systems on two variables (a and b) that gives results sometimes almost equal. The three list are not of equal length! For example: ...
0
votes
1answer
60 views

How to sum 2 tables? [on hold]

this is what we've got: ...
3
votes
1answer
58 views

How can I create a set (list) provide a kind of rule/algorithm?

Example: S = {r ∈ Q : r² < 2} Let S be the set of all rational numbers whose squares are less than 2. It follows that 1 ∈ S, 4/3 ∈ S, but 3/2 doesn't ∈ S because 9/4 ≥ 2. Thank you.
2
votes
3answers
105 views

How to multiply specific columns in a matrix of data?

So I need to make a plot of some ~2000 data points I have from a spreadsheet. I'm able to import the data just fine, it stores it like so sundat ...
3
votes
1answer
55 views

Remove values from list element, and add to other element

Basically what I need is to make a list of 400 elements, all have value 1. The next step is to create a function, that subtracts value (-1) from an element, and adds that to another element. So: ...
0
votes
0answers
110 views

Conceptual understanding of patterns [closed]

Anyone who uses Mathematica's patterns cannot be left unimpressed by its power. To gain an understanding on how it might be working internally, I thought about the process and came up in fact with ...
9
votes
5answers
700 views

Coalition Games

Suppose an election produces the following result: result = {{"a", 120}, {"b", 80}, {"c", 50}, {"d", 30}}; Letters are parties and numbers seats. To form a ...
4
votes
1answer
90 views

Random symmetric matrix

Suppose first that I want to generate a matrix whose elements are i.i.d. with distribution dist. This is easy: ...
6
votes
3answers
201 views

How to count number of observations/rows within each group

I have a huge unbalanced panel data. I want to count number of rows within each group. For example, I have the following data: ...
4
votes
3answers
120 views

Combining more than two lists by first column as index

Please bear with me. It might be easy but its been hard for me. I have say three lists: ...
2
votes
2answers
42 views

Column Operation - Subtract part of nested list from part of another nested list [duplicate]

I have two lists with x- and y-coordinates with different z-coordinates of the form {{x0, y0, z0_1}, {x1, y1, z1_1}, ..., {xn, yn, zn_1}} and ...
3
votes
2answers
87 views

Sublists of Random Permutations

What is an efficient way to create a list of (psudo)randomly chosen permutations? I'm trying to create a list like below: ...
1
vote
2answers
54 views

How to append to a list of lists elegantly [duplicate]

I have have list of lists and I would like to be able to append an element to the start of each list. I am sure there must be an elegant solution. EG: a and ...
1
vote
1answer
45 views

ListLinePlot of data imported from an Excel file [duplicate]

This is a continuation of another very similar question about how to plot structured data using ListLinePlot. Here is a sample data imported from an Excel file: ...
7
votes
3answers
197 views

Issue with very large lists in Mathematica

I have a need to work with very large arrays of data in Mathematica. The length of the list is not known upfront. The typical size is a few hundred thousands elements and could easily go beyond a ...
3
votes
1answer
71 views

How to efficiently select elements from a Hash?

How can I write an efficient version of the following selection statement: Keys[Select[hash, # < constant &]]; // AbsoluteTiming hash can be made from: ...
3
votes
2answers
80 views

Wrapping Interval Notation for Take

I'm trying to implement the solution to a math problem in Mathematica, but my code can't handle a particular boundary case. I think that I could implement a function that would do what I want it to, ...
0
votes
3answers
97 views

How to manipulate with external data?

I have a .txt file which contains a lot of triples (a, b, c) (one per row) which should be coefficients of my equation ax^2+bx+c=0. I want to include each triple in .nb file and solve each equation. ...
-2
votes
1answer
99 views

How can I produce a list of solutions for a function which is updated with updated variables using for loop?

I need to loop over a set of equations, solving for X and adding the new X value to the old X value at each step. The output I need is a list ...
10
votes
3answers
166 views

Pick with nested list

I have a list of pairs of values. Some of those pairs are invalid based on another list. I would like to select only the valid pairs. ...
6
votes
3answers
134 views

Mapping a function over the parts of a deeply nested Array

I have two tensors: tensorS = Array[Subscript[s, #1, #2, #3, #4] &, {2, 16, 16, 19}]; tensorR = Array[Subscript[r, #1, #2, #3] &, {2, 16, 19}]; ...
7
votes
4answers
381 views

Is there a way to riffle more than two lists?

I thought Riffle would generalize such that Riffle[{a,b,c},{1,2,3},{x,y,z}] would return ...
2
votes
2answers
79 views

How to make functions from datasets

I have a csv that encodes the results of plugging certain parameters (say, A and B) into certain functions (say, ...
2
votes
1answer
38 views

Manipulating lists with uneven amounts of entries

So I have a list like so list={{a},{b,c},{d,e,f},{g,h}} and the basic logic I want is to be able to manipulate each of the nested lists individually. So If I ...
6
votes
2answers
247 views

Finding the coefficient of a certain power in a generating function

I want to compute $(t^1+\dots +t^5)(t^2+\dots+ t^6)(t^3+\dots +t^9)$ and find the coefficient of $t^{15}$ for example. $t$ is an indeterminate Now in Maple this is simply as ...
0
votes
2answers
145 views

Indirect transformation based on a list of data points

I have a set of data which describes the Intensity function $Int(q)$ as a function of $q$. The data list provided below provides the shape of $Int(q)$ versus $q$.How can I use this information to ...
5
votes
1answer
119 views

How to efficiently select element in a list of lists?

How can I write an efficient version of the following statement? Cases[list, {_, feature_} /; feature < constant]; // AbsoluteTiming List is of the form, list ...
3
votes
3answers
151 views

Breaking up combined data into several smaller data sets

I have one combined data with first number as the x-value and the remaining as different y-axis values (y1,y2,y3...). How do I break this combined list, data= (x,y1,y2,y3...) into smaller lists, such ...
6
votes
2answers
204 views

Is there a bug in the Part function of Mathematica 10?

I am using Mathematica 10 now. I typed code below {{1, 2}, {2, 4}, {3, 6}, {4, 8}}[[;; , 1]][[1]] and this gives result 1 ...
2
votes
1answer
58 views

How to select elements with a specific style of a list?

Suppose I have a list: where 3 'up's of the list are red(I've made it to Cell Expression as follows). ...
3
votes
2answers
193 views

Why does a certain CSV file import properly into LibreOffice but not into Mathematica 10.0?

I'm working on a project involving data manipulation and it involves working with CSV files. I know that the files are properly formatted as when I import them into LibreOffice, all of the columns ...
6
votes
3answers
275 views

How to remove a line of a matrix if not all elements are numeric?

I have a matrix a n columns and m lines. I'd like to efficiently remove the lines that are not entirely composed of numeric ...
1
vote
1answer
52 views

Appending functions to a list [duplicate]

Could someone please explain the difference between these methods, and possibly a nicer way to get the first result? (This is a toy example and in my real program I'd like to use ...
3
votes
2answers
76 views

Is the MaximalBy function still used [closed]

On the mathematica reference website it gives examples using the MaximalBy function, However when I am using it, I see no desired output. This leads me to wonder if mathematica has stopped using this ...
2
votes
3answers
144 views

Alternatives to Append/AppendTo for generating a list in an interactive DynamicModule?

I have a stack of timelapse microscopy images that I am trying to segment frame-by-frame using some of Mathematica's image processing functions. I have created a little interactive DynamicModule with ...
7
votes
1answer
294 views

Tuples without self-loop

I have a simple question coincerning the Mathematica function Tuple. Currently, I apply the following code ...
13
votes
8answers
542 views

UnFlatten an array into a ragged matrix

Trying to unflatten an array that was part of ragged array of sub matrices. As input we have flattened array: ...
8
votes
5answers
199 views

How to do DateDifference on table items containing dates

I have a Table with data in form {{date}, value}: ...
6
votes
0answers
52 views

Listable compiled functions used in NMinimize

This is an example from MMA: cListable = Compile[{x}, (x-1)^2, RuntimeAttributes -> {Listable}] In case of single entry: ...
6
votes
5answers
287 views

Find patterns in a list

again, I have a list like this: ...
3
votes
1answer
75 views

Use Style on list elements

I have a list like this: list = {0, 0, 0, 1, 1, 1} I want to color all the 0's in red, but I dont want to count through all the elements, like in my solutions, ...
4
votes
2answers
106 views

Is there a built-in function to map a list of heads to a list of data?

Assume that this built-in function is called func. What I want is func[{f,g},{a,b,c}] will return the following result: ...