# Tagged Questions

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

333 views

### How do I create a histogram out of this datastructure: x[i] = value_i?

Here is my SSCCE: a[1] = 2; a[2] = 3; a[3] = 6; Histogram[a] This throws and error though. Here are my questions: What kind of data type is a? Is it an Array?...
547 views

### Filter list based on date

What I would like to do is remove entries from a list of instrument data when it is in maintenance. The maintenance data I have is a series of dates which look like this; ...
297 views

### How to get a sub range of a larger matrix?

This should be an easy question but I only found a partial solution using All. Say I have a matrix A = 1000 x 5, how to get only a part of that matrix, say B = n x ...
4k views

### How to convert output of a For loop into a list

I have written a For loop in my Mathematica notebook. This For loop, when activated, will generate a sequence something like: ...
543 views

### How can I force points in a list to have distinct x values?

I have a list of points that may be used for linear interpolation using Interpolation and need to ensure that no two points have the same $x$ value, since, if they ...
256 views

### Order of operations for the Table function [duplicate]

Possible Duplicate: Using pure functions in Table I have run into a situation that I do not understand when trying to generate a nested list of pure functions. I have the following code. <...
196 views

### How to efficiently find multimap k-itemset frequency

I am doing this to learn association rules. The data d is in format {id, value}, for example: ...
242 views

### Selecting a Point that has the Lowest Absolute x/y-coordinate From a List of Points

Given that there is a set of points, for example, {{3,4,2},{5,2,-1}}. How do I go about selecting the point that has the lowest absolute x, y or z-coordinate from ...
293 views

### Self-referential list or table of buttons

How could one create a table or list of buttons, such that clicking on a button removes the button itself from the list?
95 views

### Non Commutative Multiply [duplicate]

Possible Duplicate: Non-commutative symbolic linear algebra I want to multiply two matrices, for example, A = {{e, f}, {g, h}} B = {{a, b}, {c, d}} Using ...
460 views

### Convert values at level {3} in a list to percentages

I have the list ...
306 views

### Making a table with elements like {10i+j, i, j}

Table[10i+j,{i,4},{j,3}] will generate a table that looks like this: {{11,12,13},{21,22,23},{31,32,33},{41,42,43}} I would like ...
200 views

### Rearrangement of the list

I have the following list: ...
241 views

### Rearranging a biclustered matrix

I currently have a $77\times 38$ matrix, and I have used a clustering algorithm to cluster the row data and column data. The rows and columns of my matrix correspond to a list of country codes (not in ...
152 views

### Return a string from a vector containing a string and a number

I currently have a List of the form, {{String_1, 8.}, {String_2, `101.}, {String_3, 37.}, ..., {String_n, 28.}} Along with another list, ...
388 views

### DeleteCases messing with my mind

I'm losing my mind. Please tell me my laptop is doing weird things and not me. Or do I need to get committed someplace? ...
305 views

### Threading over a list of lists of lists and a list of atomic expressions

Although I solved the following problem using MapThread, I'm curious about why Thread does not work as I expect it to here. ...
717 views

### Fluorescence Correlation Spectroscopy Simulation

I am simulating Fluorescence Correlation Spectroscopy which basically involves tracking the random motion of particles in a box with periodic boundary conditions and then calculating their intensity ...
786 views

### What is the correct way to conditionally add elements to lists? [duplicate]

Possible Duplicate: How to avoid returning a Null if there is no “else” condition in an If contruct I have several situations where I need to conditionally add an element to a list, at various ...
261 views

I would like to transform the following list: ...
203 views

### Can Tuples help simplify this?

I have a list {1, 2, 3, 4} and wish to form {{{1,2},{3,4}}, {{1,3},{2,4}}, {{1,4},{2,3}}} I ended up doing it manually ...
254 views

### How to find synchronization offset?

I have 2 sets of data containing delays (audio / video). ...
308 views

### Restricted accumulation of values

Please consider the following list data. I was trying to accumulate data until the result turns positive the first time and ...
652 views

### Numbering element in descending order

How can I numbering the elements in descending order of second elements of sublists? For example, if I have the list which is ...
356 views

### Adding elements in the sublists

How can I add the elements in the sublists? For example, if I have the list which is m={{1,3},{2,3},{4,1}} then, the output that I want is ...
331 views

### Deleting a row or column of an adjacency matrix while maintaining the associated label

I am currently working with a weighted adjacency matrix for a directed graph, and it contains several 0 columns and rows. With the unaltered matrix, I am able to monitor the relations between vertices ...
311 views

### Use single ListPlot for multiple sets of data (on separate graphs)

This is the code I have working for a single set of data. Is there a way I can structure this to have multiple sets of data? ...
2k views

### Trying to generate a list of data to plot a graph with error bars. Need help creating the looping function

This is the sets of data I want to put into a form which will allow me to plot error bars from the min and max data. ...
718 views

### Thread over list in different levels

I have these two lists, both with the same length in the first dimension: ...
217 views

### How to efficiently take complement of two big lists?

I have a giant list l1 and some smaller lists l21, l21, ..., ...
342 views

### Logical operations on a list [duplicate]

Possible Duplicate: Applying And to lists of Booleans I have two lists filled with logicals: ...
410 views

### What's fastest way of defining 10^5 down values?

I want to define isGood[___] = False; isGood[#] = True & /@ list where list is a list of several million integers. ...
173 views

### Comparing Unequal Lists of Surnames to Establish Over or Under-Representation

I've been using Mathematica to explore historical records. I have two long lists (one is 69k, the second 17k) of unequal length. They are like so (FWIW, the first list is the first 40 entries from the ...
483 views

### Generate a Combination of letters by a number

I'm trying to write a function f. example: ...
6k views

### Local max/min of Mathematica data sets

Is there a way in Mathematica to find the local maxima of a set of points? Suppose you have ...
2k views

### Transform a Sum into a List

I want to turn a sum like this sum =a-b+c+d Into a List like this: sumToList[sum]={a,-b,c,d} How can I achieve this?
337 views

### How can I use Max[] in a function that is passed a list not find the max of the list

For most functions in Mathematica, passing them a list will call the function on each element of the list. For example: ...
2k views

### How to make all values positive?

So I have a list of data that contain both positive and negative values, and I am wondering what I have to do in order to make all the numbers positive.
594 views

### How to pull scalars out of a function that should act on lists?

Suppose I have A = a vecA B = b vecB where a and b are supposed to be arbitrary scalars ...
120 views

### How to evaluate the sum using values from the data being input

I have a problem in evaluating a sum using values from data I input. Suppose I have data = {1, 3, 5, 6, 8} If I want to evaluate the sum of my data (1+3+5+6+8), I ...
174 views

### Specifying form in MemberQ

This seems like a very simple question, the answer to which should be obvious to me. So I won't be offended if this question is closed. But I'm having trouble figuring out the answer. I would ...
777 views

### Using 'Reduce' to solve a set of inequalities, specified by a list

I have a two lists $LHS$ and $RHS$, both of size $n$. I want to solve a system of inequalities of the form: $$LHS[1] \leq RHS[1]$$ $$LHS[2] \leq RHS[2]$$ $$LHS[3] \leq RHS[3]$$ $$\vdots$$ LHS[n]...
140 views

### Generating continuous products or sum

This is kind of a continuation of this question. I want to automate these 2 steps on Mathematica once I give an integer $N$. generate a list of variables $\{a_i\}_{i=1}^{i=N}$ then for some ...
2k views

### Reshape vectors exactly like in MATLAB

This gives a 64×1 column vector in Mathematica: ...
2k views

### Alternatives to While Loops?

I am using Mathematica to run a probabilistic simulation. Essentially, I have a list of members of a population (they only have one, numerical, attribute, so it's just implemented as a list of ...
739 views

### Mathematica: summing over n abstract indices

This probably has a one line answer, but I'm totally stuck. I have two tensors, i.e. two objects that depend on NN abstract indices which i've labelled ...
581 views

### Calculate proportion of values for dates

At work, we were discussing when is it the best time to change to winter tires for bikes and/or cars. Using WeatherData[] and ...
501 views

### Splitting a list by specifying section headers

I have a list of strings called mylist: mylist = {"[a]", "a", "a", "[b]", "b", "b", "[ c ]", "c", "c"}; I would like to split ...