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

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2answers
119 views

Matrix conditional operation

Say I have a matrix of: tmp1 = 5; tmp2 = 5; tmp3 = RandomChoice[{0, 1, 2, 3, 4, 5}, {tmp1, tmp2}]; MatrixForm[tmp3] How to do a conditional operation of elements ...
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1answer
57 views

How to sum 2 tables? [on hold]

this is what we've got: ...
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0answers
107 views

Conceptual understanding of patterns [on hold]

Anyone who uses Mathematica's patterns cannot be left unimpressed by its power. To gain an understanding on how it might be working internally, I thought about the process and came up in fact with ...
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0answers
48 views

Generate all strings of fixed length from an alphabet [duplicate]

I am trying to create all possible strings of length $8$ from the alphabet $\{+1,-1\}$. I am trying to get help from this question. But not sure where to start from. Any help?
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0answers
105 views

Improving the speed of evaluating Table with nested functions

I am a Mathematica novice working with a stack of 1024 x 1024 WatershedComponents (or MorphologicalComponents) label matrices ...
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0answers
53 views

deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
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0answers
32 views

Grabbing columns from a matrix [duplicate]

If I have a matrix - exampleMatrix = {{A1,B1,C1},{A2,B2,C2},{A3,B3,C3}}; And I want to create a matrix like - ...
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1answer
68 views

Select duplicate values from a list [duplicate]

How can I select the duplicate values in a list? Example: {1, 2, 1, 1, 1, 1}
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1answer
81 views

how to apply a function to a list of tables

I have several files, and I want to extract for each of them a table, and then select just numbers, and keep only rows with five elements. My code works fine during import ...
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1answer
65 views

Swapping rows and columns in matrix [closed]

If I have an array like the following $\left( \begin{array}{ccc} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{array} \right)$ How can I swap the rows and columns, so it is ...
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0answers
28 views

Unexpected results from Thread [duplicate]

I've run into an issue where threading two lists with a generic function, f: Thread[f[{{1,1}, {2, 2}, {3, 3}}, {4, 5, 6}]] ...
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votes
1answer
53 views

Manipulating lists with constant values [duplicate]

let us assume we have some data in the following form. Table[data[[1,i,{1,2}]],{i,1,Length[data[[1]]]}] This would give all $x-y$ pairs of the first file. What I ...
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1answer
66 views

How to discriminate Weatherdata latitude and longitude from a more detailed list

From this list of weather data how can I discriminate only latitude longitude for each station? For example from the following sample I would need only the coordinates: "50136","","Aoluguya|Mohe, ...
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1answer
37 views

save all inputs as list [duplicate]

I received three results of calculations: {k->0.190729} {k->0.197575} {k->0.249319} Could you help me write the results in the following form: ...
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0answers
23 views

How to put the values/points in a loop into a plot? [duplicate]

I've already make the do loop..it has 200 points..how am i going to put those points into a plot?do i need to make a list@table before doing the plot?here's my loop example, ...
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0answers
78 views

How to save the results in an identical Excel file (.xls) in each iteration of a Do loop

Assume the following code (Below code is just an example to clearly illustrate my problem): ...
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0answers
37 views

Filter sublists that contain a certain value [duplicate]

This question is a followup from appending elements to sublist mergedList = { { {"a","b"}, -1.5, -5, "no" }, { {"c","d"}, -2,-10, 7 } } I ...
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votes
1answer
58 views

If statements with a Boolean [duplicate]

If I have a vector {1,2,3}, I want to write an If statement, where if one of the positions is "1", it will perform a certain command. ...
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0answers
71 views

Improving a function that filters each table from a list of tables

I have written the following function which can take in a list of tables as an arguement, and then filters each one. The function I wrote is below, and the commands I combined are listed below the ...
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0answers
43 views

Plot two functions of two variables against each other [duplicate]

I have two functions f1(n,m) and f2(n,m) but the issue is that f1 generates many values say ...
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0answers
27 views

How to switch elements i,j in a list? [duplicate]

Are there any direct function to switch elements i,j in any list? or is necessary to create one with Do / If ? (I don´t ask for making me this function if it doesn´t exists) My target is can ...
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0answers
21 views

How do I plus these values in a list [duplicate]

Hi I need to plus 3 values together each time for the rest of the list. How do I basically add the 3 sets of values together each time. When I try Plus[] it returns the same input values back to me ...
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0answers
109 views

A problem with functions and Infinite expression 1/0 encountering

Following code (function) makes integrals and then replace f[x] with Cos functions and calculate the definite parametric ...
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0answers
240 views

Nested for loop in mathematica

I have a code in mathematica with a loop which iterates over a variable i and calculates a list of numbers h given the start parameter f: ...
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0answers
68 views

Optimization of vector manipulation

I'm trying to implement an upwind scheme for solving transport equation (at first, I work with no right hand side and the simpliest case possible - velocity is constant, initial data is smooth, etc). ...
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0answers
36 views

Number precision in a list [duplicate]

I have list with elements: ...
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0answers
57 views

Given a list of pairs, average the second elements of pairs whose first elements match [duplicate]

Say this is my list: mylist={{1,4},{1,6},{1,11},{2,12},{2,14}} I want to do an operation that looks at the first element of each pairs, and for all those that ...
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0answers
28 views

Problem with slot in If statement [duplicate]

I am struggling with slots, In this case I have a function int which gives either true or false. When it gives true, I want ...
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0answers
54 views

Generating the set of all three-dimensional binary arrays distinct under rotation and reflection?

How can I automatically generate all possible three-dimensional binary arrays of size $(x_1 \times x_2 \times x_3$) where each array is distinct from all others with respect to rotation and reflection ...
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0answers
32 views

Check if a (possibly nested) list is real [duplicate]

I have a very large matrix of numbers. I want to check if all its entries are real. At the moment I am using realQ = And @@ Thread[Flatten[Im @ #] == 0] & Is ...
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0answers
32 views

Updating List with Do works but not with ParallelDo [duplicate]

I am trying to find 5 minimas for some function. I can obtain the results if I implement a simple Do function. I tried to speed it up by using ParallelDo and then my code returns spurious results. ...
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0answers
82 views
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0answers
44 views

Arithmetic operations on columns [duplicate]

I have imported a file, data.txt, then plotted columns 2 and 3 as function of column 1 using the commands below. ...
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0answers
24 views

Create a (maybe nested) list of nminimize solutions in a loop [duplicate]

I'm a total newbie in mathematica, so need some help. I understand that my question is about basics, but i couldn't find the answer in docs, google and here. Here is what i'm trying to do. ...
0
votes
1answer
215 views

Remove list elements that contain NaN Symbol [duplicate]

I have a long list of lists ...similar to g = {{1,2,3},{4,2,7}, .....{1.2,9}}. Occasionally, g contains elements like ...
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0answers
16 views

logarithmic distribution of a range in fixed number of elements [duplicate]

I want to distribute a range between 4 to 93 in 50 numbers which are logarithmically distributed. How I can do this in mathematica?
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0answers
61 views

analysing data with MLF using (Oracle) Database connection

I'm testing the MLF package in Mathematica for datamining purpose. I start the databaseconnectivity with the following code: ...
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0answers
25 views

Threading a single abscissa through a list of ordinates [duplicate]

Suppose that I have the following list, called list. list contains elements X, ...
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0answers
87 views

Select {x,y} pairs from a list where x conforms to a rule [duplicate]

I'm working on some pet project and I have a very large list of {x,y} pairs. I want to make a new list containing all {x,y} pairs where x is, let's say, even (I actually need something more ...
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0answers
43 views

Store results of inequality [duplicate]

I eveluated some values using Reduce commend and I store them in a Table ...
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0answers
63 views

How to delete duplicated sublist [duplicate]

I have a list like this: ...
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0answers
43 views

is there a way to speed up rule replace? [duplicate]

I am currently doing calculation with 7 parameters, each parameter set corresponding to a value. And I store the data in the format as a list of rule, like following ...
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0answers
27 views

Eliminate some value from a matrix [duplicate]

I have a function that return a table consisting of a 2D points. These points are either {x,y} or {0,0} ...
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votes
1answer
38 views

Pruning coordinates in subarrays of a list conditional on them having non-real components

If I have a list of 2D coordinates placed in subarrays of a data structure like the following: ...
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0answers
42 views

How to manipulate lists to get only part of the value [duplicate]

This is really a question about manipulating the output of Maximize. I have a function of 2 variables, defined thus: ...
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0answers
38 views

How do I plot cities on a Map? [duplicate]

Right now, I have the 20 cities with the most population in the world, given by the lines of code ...
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0answers
25 views
0
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1answer
149 views

Do loop - variable does not change [duplicate]

I got the follwing code which should add a '1' 100 times to an empty list. plotVals = {} Do[Append[plotVals, 1], {l, 1, Nmax}]; The output is again an empty ...
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0answers
11 views

Part::partd error on one of two similar lists [duplicate]

I have run into a problem that I can't explain. Here is the code: ...
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2answers
111 views

how to export nested list

I have a ListPlot where I extract my data again using pts1 = Cases[(*I put my list plot here*), , x_Point :> First@x, Infinity]; which gives me the data as ...