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

learn more… | top users | synonyms (4)

0
votes
0answers
29 views

FoldList[Union,…] version 8 vs version 9 [duplicate]

I have a list of matrices something like shown below A = {{{1,1,1,1,1},{2,2,2,2,2}},{{3,3,3,3,3},{4,4,4,4,4},{5,5,5,5,5}}} When I try to run the code ...
3
votes
1answer
57 views

Iteration variable in variable [duplicate]

Is it possible to create following list by some sort of iteration? {a1,a2,a3,...,a100} I cannot think of any way to append a to ...
3
votes
1answer
138 views

Union of two or more lists

I have a number of lists (only 3 shown here) ...
1
vote
0answers
40 views

Generate a list of values of a function for each value of the parameters already found

The following question is an extension of this question Find all roots of a function with parabolic cylinder functions in a range of the variable. Now I want to use the roots found to calculate a ...
1
vote
0answers
53 views

How to remove brackets from this list? [closed]

I have some lists which have many brackets. I'd like to remove brackets from the lists. For example, I need to change the list ...
2
votes
3answers
101 views

Efficient extraction of a subset

The context is molecular dynamics. The data is in the format (index_1, index_2, distance). The goal is to find all of the distances to the neighbors of point index_0 and to present a set listing the ...
6
votes
3answers
197 views

Merging lists of pairs [duplicate]

I want to add several fluorescence spectra. They are lists of the format ...
1
vote
2answers
133 views

Query in Lists Mathematica - Pivot table

Recently, I finished a simulation, and I got the following data: ...
3
votes
5answers
133 views

How to filter list of list of rules on certain condition?

For example, Solve[] returns all solutions as a list of list of rules. And mine looks something like this: ...
1
vote
2answers
73 views

Formatting a table of values

How do I display a list of values $\{a_1,a_2,\ldots,a_n\}$ in a two column format? --------- 1 | a_1 2 | a_2 3 | a_3 ...... n | a_n I tried ...
10
votes
3answers
358 views

Modifying strings in a list efficiently

I have a list of strings $\{s_1,s_2,\ldots,s_n\}$. I would like to to produce the following list of strings: $$ \{s_1<>1,\ 1<>s_2<>1,\ldots,\ 1<>s_n\} $$ In other words, I want ...
3
votes
3answers
199 views
3
votes
0answers
78 views

speed up evaluating a listable function

I apologize in advance for the vagueness, but I can't think of a more descriptive title. I am trying to find the average value of the square of BesselJ[0, x] ...
2
votes
0answers
45 views

Defining a function which takes lists as it arguments and threads over them [closed]

I want to define a function with lists as variables, which has the form like m = Table[2, {i, 5}]; f[x_, y_] = m*x + x*y; x and y are list variables; m is a ...
13
votes
4answers
353 views

I have the minimum Y value. I want to find the corresponding X value from the list [duplicate]

I have a very big file and contains data in the format of {x,y}. I got the minimum Y value by using data[[All, 2]] // Min[#] & Now I want to get the X value ...
5
votes
4answers
162 views

Create Nested List from tabular data

Im trying to create a nested list from tabular data, then onward into a nested association. I can get part way with the help of this answer but it only works for the first level. Repeated use of this ...
1
vote
2answers
58 views

Using Apply on a function with multidimensional input

I have a user defined function which takes multidimensional input, e.g a function that takes two algebraic variables a and b as well as a matrix m and computes some rule function as: ...
2
votes
3answers
92 views

How to check keys and values in nested Associations?

Considering we have a an association: ...
6
votes
1answer
94 views

Draw from a given list according to empirical distribution

I have two lists, where each time I have age-income vectors. Given the distribution of age in the first list, I would like to draw a sample with the similar distribution of age from the second list ...
7
votes
1answer
128 views

Automatically grouping words into categories

Say I have a comma-separated list of words. For example sake, let it be things I have seen during my trip to a safari zone. It would look something like that: ...
6
votes
5answers
206 views

How convert list of numbers to list of points on x-axis? [duplicate]

I have a list of real numbers, say: vec = RandomInteger[{1, 20}, 6] (* {2, 4, 7, 10, 13, 6} *) I want to convert each of these numbers to the corresponding ...
3
votes
2answers
155 views

Dot product for lists

Suppose we want to get the dot product for the following lists aa and bb, whose elements (a, ...
0
votes
0answers
60 views

Inverse Superposition

There are 4 tables that, I have written them as bellow: (m, n, s, and r are orthogonal basis. r.r=n.n=m.m=s.s=1, and m.n=n.r=...=0). a's, b's, c's and d's are coefficients and are numeric values. ...
3
votes
3answers
88 views

Combining $n$ lists [closed]

From this question, I know how to combine two lists. In fact, if $X_1,X_2, X_3$ are lists with the same length, then the command Transpose[X_1,X_2,X_3] will work in ...
6
votes
3answers
123 views

Evaluate a expression split in a list

I have a list with this format {integer, sign, integer, sign, integer}, sign being one of these: Plus, Subtract, Times, Divide. For example, let's say: ...
3
votes
0answers
104 views

Why is Thread[{ a, b }] the same as Transpose[{ a, b }]?

I understand the idea of both Thread and Transpose, but do not understand whatever nuance it is that makes Thread[{ a, b }] == Transpose[{ a, b }] Where ...
0
votes
1answer
75 views

Bin a large matrix

I have a large dataset and I'm trying to plot its scatterplot as well as an overlayed set of binned "summary" data points (in a different color of course). My intended effect is similar to this one ...
4
votes
1answer
89 views

Query Dataset to check if row contains any from a set of values

For a given keyless dataset, I can query to return the rows whose columns contain a specific value. For example: ...
2
votes
2answers
81 views

Plotting a 2D mapping of a 2 column ASCII

From my SIMS I can export the image mappings in form of a two column ASCII file. For example if it were a 5x5 pixel mapping, it would give something like this: ...
23
votes
2answers
1k views

Why do Mathematica list indices start at 1? [closed]

In most programming languages, container indices start at 0. This is not random or hardware-related; for example Dijkstra's article explains why zero-based indices make sense. What are the reasons ...
5
votes
4answers
280 views

Deleting multiple elements from a list

I have a list with many elements (189) and I want to delete certain elements from it. I have a list of elements I want deleted from it: ...
1
vote
1answer
67 views

How to specify positions in a matrix by an array?

If I have an array of sets of points such as pts = {{2,4},{1,3},{5,7}} Is there any super short command to use those pairs to output their respective elements in ...
2
votes
4answers
95 views

Reshaping list of 2D points by first coordinate

I have a list of (integer) 2d points, and I want to calculate the mean at each point in the first coordinate. So if my data is: ...
4
votes
3answers
204 views

How to combine Date and Time objects into DateTime object?

Considering a DateObject d and TimeObject t: ...
4
votes
2answers
125 views

How can I use sequence in plotting domain?

I would like to plot a function but have a domain defined elsewhere as follows: xrange = Sequence[0, 2π]; Plot[Sin[x], {x, xrange}] However, this doesn't work ...
3
votes
2answers
138 views

Format google places JSON output

I'm have some trouble formatting the Output of a 'Import' request. I get this as a return of a google places API request: ...
2
votes
5answers
192 views

Add values from a list, at positions from a list, to a matrix

I'm investigating matrix assembly and one of the things I'm trying to do is add specific values to a larger matrix based on a list which is essentially defining connectivity of nodes. For example: ...
1
vote
1answer
73 views

Factor terms by kets

I have an expression that contains several kets with numerical factors. I would like to retrieve the individual kets and store each individually as a list element. The expression is as follows: ...
0
votes
0answers
41 views
10
votes
2answers
232 views

Estimating the full width half maximum of a peak

I have a dataset of which I'm attempting to determine the full width at half maximum. A picture of the data is given below, and the dataset itself can be found here (pastebin). Now, this set has a ...
0
votes
1answer
59 views

Mining for matching elements of sets with equal divisors

This problem is extrapolated from a problem that was solved on how to manipulate lists of set outputs as a union ( Equation Autogeneration ), where the concern now is how to mine for (or attain from ...
1
vote
1answer
84 views

Absolute uncertainty and error propagation with lists [closed]

I am trying to do some error propagation using mathematica. This is my second day using the program. I am trying to take the derivative of a numerical function that is made up of the following lists. ...
1
vote
1answer
59 views

How to perform multi-columns selection and/or !MemberQ on large lists with speed?

This question (2 subquestions) is connected to How to speed up Select with MemberQ for large lists? Q1: I would like to have an alternate version of the form below to do a multi-columns selection on ...
12
votes
4answers
636 views

What's the function that takes X[Y[z___]] to Y[X[z___]]? (“swap heads”)

I've seen the operation described in the title before (basically, swap the heads of the first two levels of an expression), but I can't find it... Does anyone know the function (or idiom/incantation) ...
3
votes
0answers
70 views

Partitioning Table

I have a long vector array in the following format: ...
0
votes
0answers
63 views

Equation Autogeneration

The following is resubmitted as edit here to reflect suggested formatting corrections so indentations separate the lines neatly. I also fixed the unknown D variable which I actually meant to state as ...
1
vote
2answers
47 views

Insert several rows and problem with Return

I wanted to write myself a function that makes it possible to Insert several rows into one list. ...
0
votes
0answers
45 views

Output of List formatted strangely

I'm running a monte carlo simulation which uses random input data and performs calculations on it, and then outputs a 100 by 100 sized array with my data. The code works without a problem but for some ...
1
vote
1answer
76 views

I want the length 3 words on alphabet {0,1,2} with no two consecutive 1's [closed]

I tried this code but it doesn't work. DeleteCases[Tuples[{0, 1, 2}, 3], {_ 1, 1, _}].
0
votes
0answers
43 views

FinancialData, comparing returns accounting for different holidays

At the moment I am trying out the FinancialData feature of mathematica. I am a bit struck with the problem of dropping returns for dates of a list of different stocks not being equal for all stocks ...