# Tagged Questions

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

22 views

### How to combine several graphs in one? [on hold]

If I have table of for example 5 sets of points which form 5 curves, to plot all of them in the same graph I use this: ...
49 views

### Mathematica List Selection

I have a list which contains these elements : ...
107 views

### Merging two lists with possible different keys

This is very similar to my earlier question One to Many Lists Merge but somehow different. I have two lists, first column in each list represents its key. I want to merge these two lists. The only ...
52 views

### How to keep first observation and delete other observations of each group in unbalanced Panel data

I have a huge panel data. I want to create a new data keeping only first observation of each group. How can I achieve it? For illustrative purpose; ...
153 views

### Splitting a list of lists (part2)

This is a follow up from Splitting a list of lists . What would be a nice way to split the list l1 = {1,2,{a,b,c},3,{d,e}} into ...
57 views

### Duplicate values n-times [on hold]

I already asked how I can take the list {1,2,3} and get {1,1,1,2,2,2,3,3,3} out of it, adding degeneracy to the problem. So far ...
66 views

### Splitting a list of lists

What would be a nice way to split the list list = {1,2,3,{a,b,c},4} into {{1,2,3,a,4},{1,2,3,b,4},{1,2,3,c,4}}
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### Generate Degeneracies in List [duplicate]

I have a list with n entries and I would like to duplicate this list p times. In my case because of the Degeneracy of my Eigenvalues. For example I have {3,2,1} and it is five-fold-degenerate so that ...
385 views

### How to subtract one list from another, treating each elements as distinct?

Suppose that I have a = {"A", "A", "A", "B", "B", "C"} b = {"A", "B"} How can I subtract b from ...
93 views

### Make a new list by filtering unwanted rows

I have a list like this. ...
60 views

### How do you apply an algorithm individually to an array with many graphs

I have and array with many graphs to which I want to apply an algorithm (below) to each graph in an array that contains all my graphs. ...
101 views

### Understanding NestList with multiple functions

General question For a function f[n, a], where a is a list and n is a whole number, what is ...
137 views

### Deleting missing data with CountryData

I need to delete all of the missing entries after executing this line: ...
155 views

### How to detect outlier in data of an unknown function $f(x)$

Suppose I have an unknown function $f(x)$ that is monotonic, convex and nonlinear by definition. I somehow evaluated it at 1000 nonuniform $x$ points. By ploting these data, I found a very obvious ...
124 views

### Missing control for depth of Inner

Working on a mechanics problem, I stumbled on something peculiar: Since Inner is a generalisation of Dot, it changes its ...
70 views

### Recursive functions taking list arguments

I wish to create a function that takes lists (e.g. {plus,plus,minus,0,minus,plus}) and uses the input list to calculate a corresponding value using a set of ...
53 views

### Choosing a List as VertexWeight for a TreeGraph

I would like to map every vertex of my TreeGraph to an List. ...
44 views

### How to add a part of a list to a function?

I want to be able to add a specific portion of a list to a part of a function but this fucntion intakes 6 variables where as the list is of example: ...
82 views

### Finding an idiomatic way to express a system of linear equations

I have an $n$ x $n$ matrix $T$, where $t_{ij}$ is the element at the $i\,$th row and $j\,$th column, and unknowns $x_i$, $1\leq i \leq n$, where $$x_{n} = 1$$ $$x_{n-1} = 0$$ x_i = \sum_{1\leq j ...
153 views

### Polynomial with alternating sign coefficients from the odd degree terms of a Truncated Power Series

I'm trying to make a function that will take any truncated power series I give it, strip away all the even degree terms, then change the sign of the coefficients of every other term. So that we have a ...
76 views

### Generating increasingly longer lists from a single list

I start with an array such as {{1,1},{0,1},{-1,1}}. (1) I want to create an array from this which replaces each array inside the array with 3 new arrays, one ...
69 views

### Transform a rule to a list of rules

How can this rule a -> {1, 2, 3} be transformed into this {a -> 1, a -> 2, a -> 3} by way of a function? ...
140 views

### Complicated list slicing

Say I have a list with the structure list = {{1, {x1, y1, z1}}, {2, {x2, y2, z2}}, {3, {x3, y3, z3}}, ...} I would like to slice it such that I end up with ...
35 views

### Using List/Histogram Data As A Weighted Function?

I have a list of data points that I would like to use as a weighted fucntion. The data represents the number of particles within a bin of a particle distribution. Ultimately I would like to multiply ...
63 views

### Enumerating tuples from a larger space such that all pairs of values are present at least once

I am trying to write a function that will accept a list of N lists and returns a list of N-tuples that represent all pairs of values from the original N lists at least once. To illustrate with an ...
32 views

### Easy way to perform multiplication of two 2x2 matrices, that contain list elements?

I have two 2x2 matrices, which elements are lists (so overall structure can be complicated). I need to perform matrix multiplication of these 2x2 matrices as if the elements didn't have its inner ...
118 views

### How to download and combine S&P 500 stock prices

I want to download historical S&P 500 stock prices and combined them into one big file, having only one column of date referencing all stocks. Here is what I have do so far. ...
539 views

### What is the best way to draw a shaded table?

I'm trying to format a raster-style table with row and column headings and in which each cell is shaded according to the value in the cell, and the value of the cell is displayed in as text in a ...
10 views

### Formula to divide (group) numbers into N proportionally groups [migrated]

Lets take ideal theoretical case as example: we have 20 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 we should split these numbers into 5 groups: lowest, low, ...
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### Defining an ORIGINAL derivative function? [duplicate]

NOTE: I do not want to use the Derivative or D functions. – I want to define an original function. I began with this definition of the derivative , which resulted in: Limit[ #, h -> 0] & /@ { ...
135 views

### Get the position of the right interval

I have a list of intervals: Intervals = {{0, 1}, {1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 6}} and a list of measurements: ...
412 views

### Exclude data from a list

Let's create some random sample data data = Table[{RandomReal[{-10, 10}], RandomReal[{-10, 10}]}, {i, 1, 300}]; Then we plot them using ...
235 views

### Using 0 to create new columns in a list with Part

I just discovered a nice way to create intermediary columns in a list, and I would like to know if I can have some problem with it. It Works like this: Imagine I have this list, 5x3: ...
124 views

### How to exclude some indices in defining Table?

Suppose I define a table using Table[n, {n, -n0, n0}] (where n0 is some positive integer) but I want n not to take the value ...
89 views

### Compare 2 lists

I want to compare 2 lists. One is very large and I need to compare many times. Lets say Length[list1] I need to know how many times list1 occures in list2. Eg. list1={1, 0}, list2={1, 0, 1, 0, 1, 1} ...
44 views

### Lists of integers coprime to another list

I have two lists of integers. The first, p, is a list of primes (for example, {2,3,5,7}). The second is a list ...
61 views

### Eliminate symbols from Lists

I'm working with a list of roots of a 3rd order polynomial family, so i get a list this way: ...
103 views

### Manipulate list in function

I have some problems with lists and functions. Basically I just want to cut all entries from the right side, which contain 2. ({2,1,2} should become {2,1}) ...
416 views

### Efficient Indexed Sort

Suppose I have a preference for animals given by: orderOfAnimals = {"dogs", "cats", "fish", "elephants", "giraffe", "hamsters", "poodles"}; I'm given many data ...
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### How to express “if any component in a vector satisfies that …” in Mathematica

For example, l is a list of vectors. I need to delete from l all the vectors with any component larger than 1. How should I do ...
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### MapThread with incompatible length (How to Map twice in the same line)

l and b are two lists of vectors with different length. I need the list of vectors that is constructed by adding each member of ...
75 views

### Removing all values from a list that satisfy a given condition

Suppose I have a list, list = Table[{n}, {n, 1, 5}] (* list = {{1},{2},{3},{4},{5}} *) and I want to remove all values from this list that are greater than 3, so ...
33 views

### Error: in the part assignment is not a symbol [duplicate]

I am trying to set part of a Doubly-indexed list aInitialPopulation to cNumHeg. Specifically I am trying to set the 3rd part of the list aInitialPopulatiom[[cNodeNumber]] to cNumHeg. My (attempted) ...
115 views

### Distributing identifiers

I have a list that looks like this: {{"a",},{2010,0},{2011,10},{2012,27},{"b",},{2011,11},{2012,66},{"c",},{2010,19},{2011,20},{2012,}} I want to turn it into: ...
60 views

### Finding duplicates in a list

I have a list of integer, and I want to know if the list contains any duplicates. My code is working, but I feel there is a more straightforward way of doing this ...
112 views

### Excluding cases from Map

I'm doing operations of the form: PowerMod[#, -1, 126]+# & /@ Range[1, 125] When a number is not invertible, I don't want it to be included in the result ...