# Tagged Questions

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

289 views

### Efficient way to solve equal sums $x_1^k+x_2^k+\dots+x_5^k=y_1^k+y_2^k+\dots+y_5^k$ with Mathematica?

I need to solve the system of equations, call it $S_1$, in the integers $$x_1x_2x_3x_4x_5 = y_1y_2y_3y_4y_5$$ $$x_1^k+x_2^k+\dots+x_5^k=y_1^k+y_2^k+\dots+y_5^k,\;\; k= 2,4,6$$ I used a very ...
284 views

### Tricky selection of elements based on their position

I need to make a list of some elements from a 4D array with dimensions 4x4x4x4. I need to select the elements based on their position in the following way: name an element e(x,y,z,w); I need all the ...
130 views

### Can you form a list with elements which are terms from an equation?

Is there a command that takes an equation as an input and creates an output with a list of terms in the original equation? Something like: ...
45 views

### Generating partitions of a set with a specified size of the parts [duplicate]

I tried the following (inspired by the answer here) myList = {a, b, c}; Needs["Combinatorica"]; SetPartitions[myList] and I got this answer, ...
244 views

### How to select elements from a 4D Array?

I am very new to Mathematica (first time!) and I'm already having troubles with arrays. I basically have a 4D tensor, that is a matrix (call it M) which has for ...
141 views

### Monitor the list for changes

I wrote a function to monitor the list of variable. What it does is if the variable in list change, the changed variable will be separated from others. check the function and output ...
444 views

### How do I operate on a set of ordered pairs? [closed]

I have a calculation that will give me a lot of ordered pairs. For each such pair in a list, I want to square the elements and add them together. Here is an example of the kind of list I have ...
223 views

### How to replace Do loops by Inner

I need to replace Do loops by something else because it takes forever with big programs. I have been hinted towards Inner, but ...
419 views

### Making large tables easy to read with frozen headings and scrollbars [duplicate]

I would like to represent a table containing a large amount of information in such a way that I can (a) use scrollbars and (b) have table headings that don't scroll off the screen [just like the Free ...
136 views

### How does LongestCommonSubsequence` work?

When I recently came across this posting about LongestCommonSubsequence I was curious about how the function worked. ...
528 views

### another way to do this mapping of a two argument function

Sorry, I'm just starting to learn mathematica. I have the following two-argument function: h[{x_, y_}] := x ^ y When I do the following: ...
854 views

### Linear regression in a chosen range of points

Hi I'm absolutely newbie in Mathematica and have following problem: My list looks like {{50, 0.75}, {51, 0.76}, ..., and I want to choose a range out of my x-...
892 views

### Finding max, min, and closest root of two dimensional data

I have some data that is two dimensional (traditional (x, y) format) as so: var = {{x1, y1}, {x2, y2}, {x3, y3}} I would like to search through that large list ...
2k views

### Multiplying two dimensional data by a constant

I have a list of lists of the form: {{1, 2}, {2, 4}, {2, 8}} But I want to multiply only the second dimension of that data by a constant. I know I could do this ...
247 views

### Plotting array of vectors with conditions

Given data in the form list={{{1,2},{3,4},{5,6}},{{7,8},{9,10},{11,12}},...} a matrix where elements are 2-element vectors, what is a efficient way to plot this ...
142 views

### joining lists based on content

I have lists created by other processing steps, which are basically constituted by elements like this: ...
210 views

### Picking certain pairs according to a condition [duplicate]

I'm a Mathematica beginner and can't find out a solution to my problem. I have a list of pairs of numbers, for example something like this, but much longer: list={{2., 3.}, {3., 2.}, {5., 4.}, {4., 0.}...
174 views

### Expand List Operation

On applying a multiplication and subtraction on a list, like so: x = 2y - 4; Where y is a list containing fractions of complex numbers generated from dynamic ...
162 views

question1: (code 1 something wrong, Why? and how to overcome this to achieve the next code's effect) ...
162 views

### Rearranging a set of numbers

I have this set of numbers, that is a range of prices (ie 6-10) and a quantity of products (5) ...
670 views

### Create a table with inline conditions

I am trying to create a table with conditionals inline. For example, I'd like to create a 2 dimensional table like this: ...
475 views

### How to populate a table using a rule replacement

I am trying to populate the rows and columns of a table by using a rule replacment. To generate a table that looks like this For example Sc would be row 1, column 1. An example of a record looks ...
635 views

### How to normalize parts of matrix elements?

To normalize the last 2 or more columns of a matrix, ...
1k views

### Instruct a Table to only evaluate until a condition is fulfilled

I am looking for the way of building a Table of pairs of numbers in a fast way. My true table evaluates huge functions, and I see no way and reason to show those cumbersome expressions here. Let us ...
88 views

### Breaking up data and finding independence

Suppose I have the list with elements (either 1 or 4 as the last digit) as follows: ...
1k views

### Pass an empty list object into a function and dynamically generate its list elements

I have another question on passing a list which needs to be generated dynamically. (Sorry for posting two questions in one day...) I did some search and found a similar post here, but I think it was ...
160 views

### Statistical analysis of data-list with recurring x-values

I have a list of data as follows with repeated x-values: ...
521 views

### Replace elements in a list

Suppose that I have a list: ...
407 views

### Derivatives of list elements

Bug introduced in 8.0.0 and fixed in 9.0.0 Could someone explain the odd behavior of the Derivative function when drawing arguments from lists? We have, ...
1k views

### Importing several huge files with headers & footers

having here several files in ASCII format http://ge.tt/91rv0Jf/v/0 I want to import, while removing headers and footers and then join the several lists. ...
569 views

### Any rule of thumb for converting a simple mathematical expression into a pure function?

By simple mathematical expression I mean one with a few functions and few variables copied into MMA in a mechanical way from a math book. For example this one, giving the distance between two points ...
196 views

### Splitting list of sums into a sum of lists

I want to split a list of sums into a sum of lists For example, I'd like to turn {{x + y + z}, {x}, {y}, {z}} into ...
349 views

### Is there an equivalent of “shiftdim” of MATLAB?

Recently I'm spending my time implementing some computer vision algorithms, which usually handle a large amount of data. The problem I'm facing now is that I have to reform my video data to pass it ...