# Tagged Questions

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

31 views

### Use “FindFit” for Multi-variable Polynomial Fit

I'm interested in defining three input vectors: $L=\{L_{1}, \ldots, L_{N} \}$ $W=\{W_{1}, \ldots, W_{N} \}$ $Q=\{Q_{1}, \ldots, Q_{N} \}$ and I'm hoping to be able to input a number for each of ...
159 views

### Picking element from continnuous segment of list according to criteria

From list like: {1, 2, 3, 4, 5, 6, 20, 21, 22, 23, 24, 25, 26, 27, 28, 100, 101, 102, 103, 104} I need to pick position of number that is greatest in continuous ...
93 views

### remove unevaluated cells from table

I have created a table Tv where each row is of the form {x, y, Iv[x,y]} where Iv is some complicated numerical integral and <...
136 views

### How to FoldList over Dataset column without destroying/rebuilding Dataset?

I have a Dataset in the following form but with many more rows and a few other columns. ...
69 views

### generating random algebraic matrix using elementary operations

I generate several algebraic matrices of 12x12 where each element is a combination no repeat of the variables x, y, z and operations +, -, *, /, power, establishment (square root), any of them or any ...
122 views

### How to initialize downvalues from a list?

The For expression below initializes downvalues of a variable a from the values in a list ...
106 views

### Generation of sublists through a single list

I have a list with 25 numbers: list = Range[1, 25] What would be a simple code that could generate 44 new lists with 15 numbers each one of them? Also need to ...
79 views

### Creating a constant-valued matrix having the same dimensions as previously defined matrix

I have the dimensions of a matrix A. I would like to create a matrix B (say, of only 0's) of the same size as A. But A's dimensions are variable. Is there an efficient way using ...
99 views

### How to read a part of huge matrix saved in a TXT file as single expression?

I saved a huge matrix of numbers with dimensions {400, 4001, 2} using Put and got a TXT file formatted in the following way: <...
100 views

### How to add some element in a incomplete list

I have two list to process.Their first of each 2D part increasing monotonically and without repetition. ...
75 views

### Implementing the Cimmino method [closed]

What am I doing wrong? I am trying to implement the Cimmino method, an iterative method for the solution of linear algebraic systems. The final output should be a vector. Here is a description of the ...
82 views

### Mapping (Query) a function at multiple locations in nested data via All, Span

For this data: dt = <|"a"-> <|"x"-> 1|>,"b"-> <|"y"-> 2|>,"c"-> <|"z"->3|>|> It’s awkward when mapping the same ...
43 views

### Manipulate required to manage 3 parameters one which is a function

Let f(x)=ax(1-x) and I=[0,1]. Then f(I) is contained in I for 0≤α≤4. Take any *x*0 in I and study the iterations *x*1=f(*x*0) etc. Convergence or otherwise around the one or two fixed points (...
121 views

### ListPlot of data with small differences [duplicate]

This following is a similar question as plot data with small differences, but I am not able to solve my problem with the proposed solutions. ...
99 views

### Fourier transformation of multidimensional list [closed]

x is a list containing 7 trajectories (Dimensions[x] = {2726, 7}) of which I want to calculate the FFT. ...
165 views

### How to Convert a Matrix into an Association?

I have a matrix like this one: test = {{1, "a"}, {3, "b"}} and I want to convert it into an association like this ...
49 views

### Exporting formatted numbers [duplicate]

I would like to format numbers of a list and write them in columns to file. ...
177 views

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36 views

### extracting families with their representatives and number of repetition [closed]

There is a matrix: {{1,1,1},{1,2,1},{2,1,1},{-2,-1,-1},{1,1,-2},{1,-2,2},{2,1,-2},{1,-2,2},{-2,2,1},{1,2,2},{2,2,2}} How we can extract another matrix which ...
58 views

### How to multiply two tensor with arbitrary ranks, on one index only (like GR)?

I am writing a function which take two tensors with the same dimensions but with arbitrary ranks and multiplies them over one index, just like this example from GR: See, I couldn't use ...
34 views

### Call multiple data sets in Listplot [closed]

I am generating numerical data sets with a for loop and the table command. These data sets are named data[i], where $i$ is the counting variable of the ...
64 views

### How to group this list in to some group whose element have a same number to relate

I have this list list={{0,7},{16,0},{16,2},{12,5},{11,1},{1,20},{3,20}}; This is my current method to realize it. ...
54 views

### Random distribution of some Lists on a distinct matrix

I have 3 functions as below ...
239 views

### Plotting multiple lists together with their avarages in a single plot

I have as example multiple lists of x data (in mm) http://pastebin.com/7xwgGDsd which I want to plot against time (in sec). ...
64 views

### Finding the position of a list in a list [closed]

I have the following list ...
43 views

### Selecting elements from a list with nulls

I have this list ...
52 views

### PlotStyle with nested list

Simple Question from a Stumped Rookie: Using ListPlot, I can't get PlotStyle to look below the first level of a nested list to assign individual saturation values for each point; it assigns the ...
68 views

### Why does Repeated not work in this case?

I think I don't understand how to use Repeated. I have a list for example list={a,b,a,b,a,b,a,a,b} I want to detect whether ...
134 views

### Interesting “Tuples” application

I want to start with: {a,b},{c,d},{e,f} and end up with: {a,c,e},{a,c,f},{a,d,e},{a,d,f},{b,c,e},{b,c,f},{b,d,e},{b,d,f} ...
21 views

### Getting just a number out of a list [closed]

Witht the command dummy1 = Position[Subsets[Range[n]], {3, 4, 5}] I am getting a list of the form {{26}}. Is there any way to get just the number 26 as an ...
79 views

### ListPlot problem

I have the following example: x = {1, 2, 3, 4} y = {{1, 2, 3, 4}, {2, 3, 4, 5}, {3, 4, 5, 6}, {4, 5, 6, 7}} Now I can plot: ...
73 views

### Built-in (or Terse) Method to Combine and Transpose Datasets

From some calculations I have ended with Datasets of the form: ...
62 views

### Export list in 4 columns without curly brackets

I have generated the following list: http://pastebin.com/vmtRrfcD (updated) The dimension of the list is ...
127 views

### Extracting *firstly roots* from some lists to plot their pairs values

I have two different lists as list1 and list2. Their ListPlot3D of them are: and As shown in these plots, there are some points of which ...
34 views

### Struggling to Apply “Differences” [duplicate]

It looks like the following code should work, and allow it spits out error messages saying I have too many arguments, the code spit out after the error message looks like exactly what I want to ...
103 views

### Uniting lists of lists

Here's what I'm trying to do. First a simple example: ...
111 views

Suppose I have a list of the form: list = {a, b, {c, d}, f, {g, h}} i.e. an element of the list could be another list. I want to 'thread' each element of the ...
55 views

### Manipulation of imported Datafile

Since I am solving a differential equation in a for loop with NDSolve ...
77 views

### Apply function to a part of a list [closed]

Let's say I have some data: data={{a1,b1},{a2,b2},{a3,b3},{a4,b4},...} and I would like to apply the function: f1[x_]=x*5 to ...
48 views

### ListPlot of a complex data file

Here are some sample data: ...
121 views

### Filters on image vs data

I was using GaussianFilter and realized that applying it to an array yields a different result from applying it to an image. For instance: ...
126 views

### Plotting a table with many y values

I'm trying to plot a bifurcation map for a Lorenz System. I have a function (called estables in the code that follows) which, for a certain value r, returns the ...
169 views

### Looking for a better way to delete an arbitrary list of rows from a matrix

Delete is not suitable to delete the rows of a matrix, as illustrated below: ...
125 views

### Basic Programming in Mathematica - How to build a loop [closed]

I want to build a loop with the following rules: I have a list a={5,7,8,9,5,6,8,6,7,8}. I want to print the mean of the first two ...
231 views

### Exclude overlapping lists while keeping disjoint- and sub-lists?

Consider a function f[l1_List,l2_List] which is given lists of integers. Whenever two of the lists contain completely disjoint sets of integers OR one of the lists ...
135 views

### Select non-zero elements [duplicate]

I have a function that generates a list of numbers and variables . e.g. F[w]= {wx, wy, 5, 0} I want to select all non-zero elements i.e. ...
146 views

### What is an efficient way to pick out consecutive, same first-letter words from a list?

Taking a list of words, I'd like to pick out consecutive words that start with the same letter. The output should be a list of these pairs. The following is relatively slow: ...
52 views

### How to get a speicifc element from unknown number of lists?

I have a mathematica function that returns a list of the form: ...