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

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0
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1answer
46 views

convert list to equation form

Suppose I have a list condition={f'[t]-3,g'[t]-f[t]} and now I want to use DSolve on it so I need to convert the list to ...
5
votes
2answers
107 views

How to use Manipulate to cycle through a list of lists over a function

So I can do something like this which I like: Manipulate[i, {i, {1,2,3,4}}] It lets me pick which specific values I want to allow to be chosen for my function. ...
1
vote
1answer
214 views

Lookup construction using data matrix and Reap/Sow versus AppendTo`s

I am a user of MMA9 and made my own kind of Lookup, which is now a standard command in Version 10. In my program there is a section in which by means of a StringReplace[ ]-command containing a lot of ...
1
vote
2answers
125 views

How to join several list interleaving with some fixed list between?

How to join several list putting some fixed list between? Like this MyJoin[{{a,b},{c,d},{e,f}},{x}] giving ...
0
votes
1answer
49 views

Organizing and displaying list-like result

This is most likely a piece of cake for you guys, but it is difficult for me. Related to a math problem, I examine if ...
1
vote
1answer
60 views

Replacing members of a list with elements sampled without replacement from another list

I have a list of element pairs: pairList = {{1,2}, {2, 3}, {3, 4}, {4, 5}}; I'd list to pick a subset of the elements in this list: ...
0
votes
1answer
46 views

Help for properly writing simple derivative expression

I need help to write the following expression (only 1 iteration): f(x) = ...some basic function... f[X0,...,Xp] = f(p)(x0) / p! What I have so far: ...
10
votes
1answer
197 views

Max element of a list with a custom ordering function

I need a function to find max element of a list according to some custom ordering function, assuming that the function implements a total order (elements being compared might not even be numbers). ...
4
votes
4answers
171 views

Extract Specific Dates from DateList

Hopefully this is an easy question but I couldn't find an easy answer anyway. Surely there is some simple way to splice this... I want to take a large datelist in the format of {{2014,12,31}, value} ...
8
votes
6answers
285 views

Adding list of list to a list

Hello I need some help on how to add a list to a list of list. The program would have to do as below: {{0,0}, {0}, {0,0,0}}+{1,2,3,4,5,6} will give ...
3
votes
2answers
105 views

Counting the total number of instances of some collection of objects in a list

I have a list of some sort list = {"l1","l2","l3","l4"} and I'd like to count the sum total number of occurrences of n of the ...
1
vote
1answer
105 views

How to specify x axis values in the ListPlot[] [closed]

I am using ListPlot[] to plot a list of 1000 values. I need to specify the value shown in x-axis.It seems that is a classic question but I have looked for in this forum but I did not get any response ...
2
votes
2answers
172 views

Trying to Figure Out how to work with datasets & Classify[] and Predict[]

I'm new to Mathematica and I'm a bit overwhelmed. I have always used R for my statistics problems. Now that I'm trying to replicate what I do in R in Mathematica I'm making little progress. For ...
5
votes
3answers
253 views

Multiplying block matrices

I have a 2*8 matrix A, and a 2*8*2 matrix B. So B[[1]] and B[[2]] are both 8*2 matrices. I need a neat way to multiply A by B so that the first list in the result is A.B[[1]] and the second list ...
2
votes
2answers
99 views

Using `Fold` to show stages of Euler product formula

I would like to recursively replicate each stage of the Euler product proof. This does it: ...
2
votes
3answers
253 views

Picking items from a list

There's probably a Mathematica primitive to do this, but I don't know what it is...suppose I wanted to construct a list of all integers from $1$ to $n$ that were not divisible by $12$, and that were ...
3
votes
3answers
171 views

How to Update 2D List based on a binary array

I have 3 lists: numbers = {{1, 2}, {3, 4}, {5, 6}}; toUpdate = {{1, 0}, {0, 0}, {1, 1}}; newValues = {{10, 20}, {30, 40}, {50,60}}; I have to update the list ...
0
votes
0answers
76 views

Fourier Transformation of a List

As we know the FourierTransform goes a function of t ,for example, f[t] to ...
9
votes
3answers
210 views

Truncating a list once all members of a set have appeared?

Consider if you would the case where we have some list of elements: list0 = {54, 4, 7, 9, 3, 54, 4, 20, 2, 456, 2, 3}; And we have some target list: ...
1
vote
1answer
44 views

Nested list element at position specified by a list

I'm trying to avoid constructions like Y[[X[[1]], X[[2]], X[[3]]]]. That is we have a nested list (Y) of depth $n$ and another ...
0
votes
1answer
199 views

How do I plot results of complicated calculations in Mathematica?

I am new to Mathematica and am struggling with making plots of how features of solutions vary with parameters. For example, I can find the eigenvalues and zeroes of a Sturm Liouville problem (showing ...
1
vote
1answer
60 views

Shifting Columns in an Array Efficiently

I am trying to find a more efficient way to shift the columns of the partitions of an array according to a defined slope and fill in the shifted regions with zeros I have done it below but, I know it ...
2
votes
0answers
54 views

pattern matching and applying a function, not working as expected [duplicate]

Consider the following code G[x, y] /. a_[b__] -> Total[a @@@ Permutations[List[b]]] I expect it to give G[x, y]+G[y,x] ...
0
votes
1answer
62 views

ListPicker delayed output

I'm trying to make a wrapper for ListPicker that delays updating the list unless Ctrl or Shift is released. The aim is to allow nested ...
1
vote
2answers
120 views

GPA calculation from a set of randomly generated marks obtained

So, this is a homework question posed by my teacher: "A student has 10 courses. Find the ceiling value of the obtained marks and corresponding grade according to the following data Print the result ...
1
vote
2answers
69 views

how to get continuation of square matrices with periodic diagonal band automatically?

I want write a function that can automatically analyze any square matrices with periodic band diagonals and give continuations of them. But I can't figure out an elegant way to do this. Suppose we ...
3
votes
1answer
144 views

Function that returns the second argument of Reap

I'm trying to create a function that returns only the second argument of Reap. Here's my naive guess of how it would go : Reap2[x_]:= Flatten[Reap[x][[2]],1] ...
3
votes
3answers
130 views

Finding largest Range in a list

In a list of positive integers, I would like to find the largest n such that Range[n] is a subset of the list. So for example ...
6
votes
3answers
349 views

Better answer to Santa's riddle about sum of a number's divisors?

I was hoping to find an elegant solution to this riddle, using only a line or two of Mathematica: Santa Claus was telling one of his elves: "If I multiply the age of three of my reindeer, I get ...
2
votes
5answers
123 views

GatherBy based on condition imposed on index variable

Excuse me. This might be user specific question but I need your help. I have an indexed data, where positive integers are used for indexing data. I am trying to group data putting condition on index ...
1
vote
0answers
45 views

Problem with ParallelTable in using externaly defined iterator [closed]

In order to reduce my computation time, I'm making some tests with parallel computation, especially with ParallelTable. Here is a simple code : ...
5
votes
2answers
159 views

TemporalData, RandomFunction, Loops: Extracting data from TemporalData sets?

I'm doing a finance project for my differential equations class to explore stochastic processes. I'm exploring IRA retirement funds. From the project write-up: Standing assumption: at time of ...
2
votes
1answer
98 views

Why is Nearest not giving me expected result

I have the following list: numbers={0.,0.6,0.8,1.,1.2,1.4,1.8} Then I calculate the midpoints: ...
0
votes
0answers
41 views

Regarding Cycles and Lists of Functions

So, I'm trying to determine the Normal Matrix of a Least Squares Aproximation; I have a basis constituted by 8 functions f1,f2...f8; I have 9 points which constitute Datax = {x1,x2...x9} Now, I ...
0
votes
1answer
78 views

for loop and list

I'm new to Mathematica. I want to built a function like that; ...
2
votes
1answer
111 views

Request for Explanation in case of Replacement not working

The 2 code snippets work on a matrix ABg with 22 rows and two columns containing Strings. Some entries in column 2 are List { } to be recognized by the first Character "{". In the list some items must ...
1
vote
1answer
82 views
1
vote
0answers
47 views

Creating a List with Lists as entries [closed]

I'm trying to create a list A which contains 8 same elements. Each of the elements look like {0, 0, 0, 0}. I was able to do it ...
2
votes
4answers
83 views

While subpartitioning the elements in list using GatherBy, can I corresponding subpartition the elements of an unrelated list?

If we have a list like the following: list1 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; And we use GatherBy to subpartition is according to a test function ...
1
vote
2answers
45 views

Subpartitioning elements of a list based on some h[ri] == h[rj] test

If we have a list of elements: list = {r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12}; I'd like to further partition the elements into sets where, for some ...
2
votes
3answers
59 views
0
votes
1answer
68 views

How to add an extra column to a current matrix (list)? [duplicate]

a = {{-800, 1712}, {-801, 1713}, {-806, 1832}} TableForm[a] b = a[[All, 2]] - Min[a[[All, 2]]] How do I make a new matrix (list) whic looks like this ...
1
vote
2answers
48 views

Creating a list of triangle-square numbers up to n_

I have to, for a class, create a function that gives you the triangular-square numbers up to n. That said, here's the code I have: ...
0
votes
4answers
91 views

how can one select elements from a list that are satisfied a criteria which need to compare with other elements in the list?

For example: I want to select elements from a list {1,4,3,2,5} that are bigger than its previous element. {4,5} satisfies the criteria: 4 is greater than 1 and 5 is greater than 2(Ignore the first ...
3
votes
4answers
118 views

Use a categorical argument to add one layer of list structure

Consider the following nested list x = {{1,2,a}, {3,4,a}, {8,11,b}, {12,3,a}, {4,3,b}, {3,2,c}} I want to use the categorical variable ...
2
votes
2answers
88 views

Insert at specific resulting positions in multidimensional list?

I have an initial "multidimensional" list (that is, a list that is not a vector): list0 = {{1},{2,3,4},{3,4},{5}}; and I want to insert elements ...
1
vote
2answers
75 views

Insert at specific resulting positions?

I have an initial list: list0 = {1,2,3,4,5}; and I want to insert {a,x} at specific positions ...
0
votes
1answer
53 views

Plotting data from specific column

I have data like this: 1406998993.147 73 TCP_MISS/200 22284, 1406998993.158 109 TCP_MISS/200 83827, 1406998993.197 111 TCP_MISS/200 57020, If I want to plot the column 1 and ...
1
vote
1answer
97 views

Constructing new lists using Table

I tried to modify an old notebook to show a spreadsheet style output in a table. I am not getting any errors when it runs, so I think the data I am gathering and the new variables I added, ...