Questions on systematic data handling and analysis, including data correction, manipulation, or selection of user-data or built-in data available with Mathematica.

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2
votes
2answers
135 views

How do I partition a matrix?

I have a data file with fields x y z. When I import it to "data", I get a matrix if the form: ...
5
votes
1answer
365 views

Why should we make sure the calculated MD5 is of length 32?

I see when people write code on calculating MD5, (even in the documentation), they write like this: IntegerString[Hash[something, "MD5"], 16, 32] But I think ...
2
votes
2answers
118 views

FindDistributionParameters gives an error for a mixture of user defined sinh-arcsinh distributions

I have some data (1593 values). I first binned it using the Knuth rule and fitted a function that is a linear combination of two sinh-arcsinh functions. I then ...
0
votes
2answers
92 views

how to read a list from a file which has mixed types of data?

I need to read in a file with the first several lines reading as ...
1
vote
2answers
336 views

How to Fit experimental data with 4D ParametricNDSolve?

Let me first explain the background problem. I'm trying to solve a problem with a projectile motion in 4D such that the position vector is: $\boldsymbol{r}(t)=\boldsymbol{r}[x(t),y(t),z(t)]$ I have ...
1
vote
2answers
172 views

Slicing multidimensional table

Say I have a multidimensional list created in the following way grid= Table[{i, j+1, k+2}, {i, 0, 1}, {j, 0, 1}, {k, 0, 1}] grid={{{{0, 1, 2}, {0, 1, 3}}, {{0, 2, 2}, {0, 2, 3}}}, {{{1, ...
1
vote
1answer
88 views

Importing Data Issue, Breaking Up Elements

I am trying to import a comma delimited text file as a Table and I am having two issues: First, the file imports all of the numbers that should be separate columns as a single string. This is not ...
0
votes
1answer
81 views

Loop and list all p-values

I have the following mathematica code (see below). Is there a way to iterate this approach in such a way to get the p-value results of each test in a list? I would like to get say 1000 p-values for ...
3
votes
2answers
90 views

Manipulation of .csv imported data — no blanks in either of two lists

Above is a .csv file. I am trying to construct two lists of male and female math test scores such that only districts which include info for both male and female students are included i.e. neither ...
5
votes
0answers
55 views

Built-in way to handle uncertainty in measurment and physical constants?

Is there a built-in or fairly elegant way to handle uncertainties in measurement data and/or physical constants? For instance, the 2010 CODATA for the elementary charge is given as $\mathsf{1.602 176 ...
2
votes
2answers
96 views

Extracting coordinates from a ListLinePlot

I used an iterative method to resolve equations, then i plotted the results using ListLinePlot. Unfortunately, now I need to use some of the data that was plot. I know the X-coordinate, and need to ...
7
votes
2answers
407 views

Find fit of an experimental PDF

After quite some struggle, I managed to put up a code that is syntaxically correct. The goal is to find the parameters for a gamma distribution that best match experimental data. The data is a set of ...
1
vote
1answer
111 views

Data plotting to estimate answers

I have some data such that I am estimating the time taken by system to reach at some stage. For example. 1 sec to reach at stage 1, 3 seconds to reach at stage 2, 5 seconds to reach at stage 3 and so ...
1
vote
1answer
68 views

Simple pick up an element from above line [duplicate]

( Did not readily find from Documentation even if used before). NSolve[ 2 x^3 + x ^2 - 5 x + 2 == 0, x] How to collect roots with new labels a,b and c?
8
votes
4answers
834 views

Replacing a for-loop with something functional

I'm a physics grad and have been using Mathematica mostly for data visualization. The evaluation part I normally do with C/Python, but I've been wanting to try out Mathematica for these tasks, too. ...
8
votes
3answers
468 views

Turning a set of random walk data 45 degrees

I have a set of data that is just a "random" (generated by me, not by computer) sequence of length 2000 of 1's and (-1)'s. I used it to plot a 1-D random walk where +1 is step up, (-1) is step down, ...
2
votes
2answers
359 views

Using Periodogram to investigate the seasonality of the data

After asking how to get rid of the seasonality of this set of data, I'd like to ask how to investigate the seasonality in data using Mathematica. Which tool would you use to study seasonality? I.e. ...
4
votes
2answers
217 views

Deseasonalize the data of traffic growth for the past data

In another question (Using TimeSeriesForecast for forecasting the traffic growth) I asked to use the TimeSeriesForecast on this set of data the answer provided the plot with and without the ...
3
votes
2answers
214 views

How can I create a 3D representation of an object with known coordinates and adjacency table in mathematica?

Basically I want to create an object with specified coordinates and adjacency table, like in page two of this article. I'm completely new to using Mathematica, any help would be great! EDIT: So I ...
1
vote
1answer
88 views

Data Table Manipulation in Mathematica 10

I would like to select columns from a table by column name. I tried the solution described here: Data Table Manipulation in Mathematica: Step 2 . I am using Mathematica 10. (I would write a comment ...
3
votes
1answer
90 views

How do I find local minimums in data? [duplicate]

Mathematica easily allows you to use FindPeaks to find local maxima in your data is there any equivalent function for finding local minima?
3
votes
2answers
196 views

Entropy of the elements of a general data set

I have the following data set, and wish to track the evolution of the entropy of each element within the set. I have evaluated the entropy for some elements, but how does one evaluate the entropy of ...
0
votes
1answer
75 views

Working on a certain column after importing data from a file

I'm trying to import a file with 2 columns, in TSV format. Something like this: ...
1
vote
3answers
254 views

Read data from file starting at a certain point

I have files of data that come with a whole bunch of junk in the beginning before the actual columns of data start. Is there any way to tell Mathematica to start putting the data into a table from ...
0
votes
1answer
65 views

Selecting elements from a list [duplicate]

I have the following array of numbers: a = {{0, 2, 5}, {3, 5, 1}, {4, 0, 5}, {8, 3, 4}, {0, 8, 6}}; then I make a list of the first row with ...
1
vote
2answers
100 views

Entering coordinates of 2D points using the keyboard

I am studying the singular points of a triangle. I need to get the vertices of the triangle and then work with them. I have worked with the function Input, but I ...
0
votes
2answers
68 views

Fitting data in form $f = f_0 + c A^x$ [closed]

The Fit[] function in Mathematica can fit data in form of $f = f_0+c_1x+c_2x^2+...$ ($f_0$ and $c_i$ are unknown constants), is there a function can fit date in ...
2
votes
3answers
573 views

Plot a table of lists

I want to make a point plot of a table with lists in it. Assume I have data like this: data={{1,2,3,4},{5,6},{1,5},{2,4}}; and now I want to make a point plot ...
1
vote
1answer
154 views

A bug won't let me import JSON files

I have been working on a project and I have been using JSON to build some networks, the code I use is: ...
2
votes
1answer
207 views

Export generated mesh

Say I have generated a mesh using ToElementMesh, following one of the examples here: http://reference.wolfram.com/language/FEMDocumentation/ref/ToElementMesh.html ...
4
votes
0answers
110 views

How to efficiently read data from any part inside huge file [duplicate]

I have a data file (over 2.5 GB) and I want to do calculations on the data. At first I used. data=ReadList["file", Record,n] I still have three problems: 1- ...
1
vote
1answer
97 views
3
votes
3answers
187 views

Plot a bunch of lines in 3D from point data

I have a 12*25 array, wherein each entry is of the form $\{x,y,z\}$. So 12 different $x$ values, 25 different $y$ values and 12*15 $z$ values in all. I'd like to plot 12 curves of various $x$ values ...
0
votes
1answer
43 views

Is there a limit for DensityHistogram data amount?

I'm trying Mathematica for first time and while trying to do a Density Histogram with around 300 000 points, I get an error "THE INPUTED DATA is not a valid dataset or list of datasets." Maybe it's ...
8
votes
1answer
196 views

Is Mathematica's (v10.0.2) NetCDF exporter broken? [duplicate]

I'm trying something very simple, namely: Export["file.nc", {"Datasets" -> {"seqs" -> {"AAA", "BBB"}}}, "Rules"] And getting Java errors about "illegal ...
2
votes
1answer
121 views

Finding periodicity of multidimensional data?

I have a data set consisting of measurements of an $n$-dimensional vector $\mathbf{x}(t)$, at $N$ distinct time points $t_i$. The time points $t_i$ are equally spaced. I need to find the dominant ...
0
votes
1answer
102 views

Binomial Regression where n > 1

I am not well versed in Generalized Linear Models, but am trying to use this approach to model some discrete data. I have binomial data where the sample size for each observation is the same size, ...
0
votes
1answer
71 views

How to fit this data to be used in NIntegrate later?

I have a list of data points that resemble a chi-squared distribution (long tailed gaussian) that I am having trouble fitting or finding an equation with. The goal is to use the fitted equation in an ...
3
votes
3answers
977 views

Import data from first/last 100 rows of a file

If one wants import data from the first three rows of a file "myfile.data", one can use the command Import["myfile.data",{"Data",{1,2,3},All}]; However, if I ...
0
votes
1answer
82 views

How to assign the array data to variables?

A very basic question but puzzled me for long time on how to assign array to variables. For instance, we have array {{t1,x1},{t2,x2}...{tn,xn}} how to assign the first element to variable t and ...
4
votes
1answer
132 views

Most efficient searching algorithm in a table

I am completely new in Mathematica (and in data analysis in general) and I find it really useful, although I still do not use it properly. I have the following question related to data manipulation: ...
1
vote
1answer
73 views

FindClusters memory exception problem in dealing with 1Dimensional data?

data=RandomReal[10,{30000}]; FindClusters[data,2]; Why in this little data set, FindClusters Load so much memory? and ...
1
vote
1answer
83 views

List Manipulation and Removing Cases

I've imported a large data set, manually removing headers in the .rtf file where it originates. However, when I import this data, I receive this output: ...
1
vote
1answer
73 views

Performance of Extract-Transform operations

I'm doing simple data analysis, where I load some "date-time" data from a file. The data is a simple list, but there are 41,000 values in total. Here's a short sample: ...
1
vote
1answer
101 views

FinancialData Input

What does the function FinancialData require as input for natural gas: http://finance.yahoo.com/q?s=NGG15.NYM Is it easier to export the natural gas data to ...
6
votes
2answers
242 views

Building bounded polygon around heatmap (or points)

I have a set of data for world marine piracy. I'd like to build polygons encircling areas of active piracy. So to start with I get piracy data and make a heatmap from it. ...
28
votes
1answer
587 views

Visual representation of a Ranking over time (image provided)

[Disclaimer: I initially posted this question on stackOverflow 2 months ago and think it might be better suited for this forum (link to original question)] The graph below shows a ranking of ...
1
vote
1answer
188 views

Mixture coefficients and Parameter estimation for moving Normal distributions

I am searching for a way to do the following steps below. I am stumped and I have stumped a few profs too. Any help would be appreciated. I would like to import data from, say, excel or a .txt file ...
1
vote
1answer
155 views

ReadList can't read “.csv” data with correct line number?

Well, the problem was solved today. Since "testAll.csv" is generated by Java/Eclipse, and I noticed that the LineSeperator is ...
3
votes
3answers
209 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 ...