Tagged Questions

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

865 views

histogram fit for probability density [closed]

I am trying to fit the (probability density) histogram of some data with the exponential function, but I am having difficulties. My raw data are in file called ...
311 views

How to read non-standard-format data into Mathematica from a file

I would like to read non-standard-format data into Mathematica from a file. How can this be achieved? For example, how can I read the following text file of data into Mathematica: ...
596 views

For-loop not working as I expect

I want to do this: When 10 <= t < 130, give t -> 1; When 130 <= t<300, give ...
154 views

Find Numerical Derivatives (With Errors) given some data

I have a question. Suposse I have some data with their respective errors: ...
281 views

Assign the contents of a “Copy” operation programmatically to a variable?

While an earlier question Cut and paste data from a spreadsheet nominally addresses the issue, a year has past since its OP asked it and I hope that others have come across simpler or more direct ...
271 views

Multi-Fitting with Nonlinear model

I want to fit experimental data by the H-N model. Here is the H-N model: \text{EHN}(T)\text{=}\text{E$\infty$}+\frac{\text{E0}-\text{E$\infty$}}{\left(1+\left(i \omega\tau(T_g)10^{-\frac{\text{C1} ...
2k views

Graph databases / Nosql with Mathematica

I am very new to mathematica but it looks like an interesting language and I would like to explore it for a future project to create a web search engine. It seems like it would be fairly well suited ...
2k views

Moving maximum function?

How can I construct a moving maximum function? For example, if I have a list of 12 values: { 5, 6, 9, 3, 2, 6, 7, 8, 1, 1, 4, 7 } and I want to maximize over 3 ...
414 views

Determing two Nonlinear model fits with 95% confidence bands from one data set

I have the following data which is postulated to have contributions from two different sources .....as can be seen from the confidence band, many points are out of the band. Question: How can I ...
267 views

How to get an equivalent of WeightedData in Mathematica 8?

Is there an equivalent command of WeightedData (new in version 9) in Mathematica 8 or I have to define it by myself? I haven't found anything in the site or ...
131 views

WeatherData function problem: “NonMetricValue” returns undated list of values

In the WL example below, WeatherData[] returns an undated list of values when I add the annotation "NonMetricValue." ...
319 views

FindFit not giving a good fit despite good initial parameters

I'm having a problem with FindFit not giving a good fit to my data, even though the initial parameters I give look really good when plotted. The fitting function is ...
70 views

How to save all variables in the workspace into a file? [duplicate]

I did some time consuming computation and obtained a lot of arrays and variables; however after restart the Mathematica Kernel, all these computational results disappeared. How can I save all these ...
4k views

Finding fourier transform of data and hence frequencies

I looked at all the other questions related to mine before posting this, and they didn't solve my problem. I have a large data set which can be downloaded from here. I'm using the following code to ...
862 views

Having trouble fitting data using NonlinearModelFit

I'm trying to fit data = {{2002, 45000}, {2004, 90000}, {2005, 120000}, {2013, 211000}}; to an exponential function ...
1k views

Filtering and Replacing outliers

I have a set of data that measurements of temperature vs time (date). It is easy to realize when the sensor went wrong as one might see a blip on the data. How to teach to Mathematica to: 1) Detect ...
265 views

How to reconstruct a missing data point

In the output of a large computer simulation(thousands of cpus for 3 days), I found that one data point is missing in the result. Is it possible to reconstruct the missing value using the remaining ...
614 views

How do I find the maximum value from the given set of data?

I have a set of data like {{x1, y1},{x2, y2}, ...,{xn, yn}}. From this data can I find the value of x for which ...
277 views

importing large data files with a constraint

As I have learned in this community, one way to import a hefty data files (e.g. millions of rows of {x1, y1} data) if you don't care about the individual elements (maybe just want to obtain some ...
177 views

How to adjust the correct ImageSize between two plots

Let's consider the following simple plot ...
172 views

I need a technique for determining and drawing a line where the density in a listplot jumps up suddenly

Basically I have a two dimensional list plot with a bunch of points between the square of (0,0) and (1,1). The y-values of these points are drawn from a uniform probability distribution between 0 and ...
278 views

Need help in making a fit to my experimental data

This is what I have done so far. The points are of angles-of-deviation and wavelengths from my physics lab experiment. ...
69 views

How to extract data beginning on the closest number to zero?

I have a list from which I want to extract only the values beginning from where b (from {a,b}) is the closest to zero. For example: I want extract data={{2, -0.036704}, {56.7499, 0.95489}, {73.7349, 0....
645 views

Need help with extracting columns from a table

I'm trying to clean a dataset of unnecessary variables but I constantly get an error when doing so. Following an example where: ...
258 views

Implement planar correction for skewed 3D profilometric data

I have some data that represents small-scale surface topography. The data is planar but not flat because it's impractical to level this microscope to a tolerance of microns. It looks like this: I'd ...
123 views

How to extract data depending on Position of First zero?

I have a file (attached as an image) which I imported to Mathematica and only extracted the first and second column. My problem is that I want to extract the data beginning from the row where $A=0$. ...
44 views

How can I convert a matrix into matlab form string? [duplicate]

How can I convert a matrix into matlab form? ...
431 views

How to delete all rows in datafile that contain a string

I'm importing some data from a file. However, the file was created by an unreliable instrument, such that the data looks like this: ...
265 views

I have a lot of 32-bit numbers in hexadecimal symbolized as they are in C (for example, 0x1230abde). How can easily read these in Mathematica?
282 views

Import numeric data into Mathematica

I have a C++ program that outputs a set of numbers at each time step. A blank line separates successive time steps. Here is an example of my data format: ...
347 views

Selecting for 2D points that are within a threshold distance of an upper- and lower-bound number of points

I have a very large set of 2D points: numberOf2DPoints = 10^6; pointList = RandomReal[{0, 1000}, {numberOf2DPoints, 2}]; I'd like to find a way to quickly ...
162 views

Reading between blank lines in external data files

I have an external data file with several columns and thousands lines of data. For the sake of this question, let's assume that we use ...
105 views

Missing something in my input for CountryData dependencies

I'm trying to find (a)which countries have dependencies (b)and a list of countries that consider themselves dependencies (c)and a list of countries that don't consider themselves dependencies. ...
174 views

Understanding distribution chart

How to explain DistributionChart function in mathematica, For example: if I have ...
231 views

Judging the quality of fitting an EventData object to a distribution using LogRankTest

I have $389$ data points defined in an EventData object and want to judge the quality of fit of this data to a fitted $3$-parameter Weibull distribution. This ...
244 views

How to Use ProbabilityScalePlot with Censored Data?

I am trying to reproduce a ProbabilityScalePlot of censored data shown here (see Sample Analysis Plot). Here is my Mathematica code. First I deal with the uncensored case. ...
112 views

Why does Rescale performance vary significantly based on the real number values in a list?

I have a list of the form: testList = Table[{Flatten[RandomReal[{-200, 200}, {1, 2}], 1], RandomReal[{-200, 200}, {69, 2}]}, {i, 1, 100}]; And I would like to ...
524 views

How to exclude some points to make them more evenly distributed in a figure

If there are some points in a figure, how can I exclude some points to make them more evenly in the figure? 'Evenly' here can be defined as the number of points in each $0.01*0.01$ box is at most one. ...
890 views

Relational joining of tables

A common thing to want to do with data is to combine it (at least I thought this was a common thing). In SQL there is the idea of table joins "select id,v1,v2 from A,B where A.id=B.id" kind of thing. ...
68 views

Delete x,y,z occurrence (or any permutation of it) from parent data set (dynamically)?

Simple question: I would like to dynamically specify a list of 3 elements, {x,y,z}. Then I'd like to find that list, or any of its permutations, in a parent data ...
610 views

WaveletScalogram in polar coordinates

For given dataset data = Re[Zeta[1/2 + I Range[0, 100, 0.01]]]; It is nice that Mathematica can plot data in both Cartesian and Polar coordinates. ...
2k views

How to extract data from contour plot as a text file?

I have the following expression from which I want to extract data for a contour plot. ...
245 views

Compute percentages in a list

I have a data file which contains thousands of lines and each line has eight elements. Here is a small sample of the data file ...
3k views

Find a best fitting curve for some data with no regular pattern

Suppose some data with no regular pattern is given, so common patterns of functions all fail to fit it. Then how can one find the best fitting curve? I believe there will be some data for which we can ...
936 views

How do I make a frequency table from a histogram (data set)?

I have a data set. ...
202 views

Using Select on list of vectors [duplicate]

I have a dataset, where each element in the list is a vector as in data = Table[{i, 2 i, 3 i}, {i, 1, 10}] As an example, I am interested in the entries where ...
199 views

Extracting values

I have imported a data from an excel sheet. I want to extract parts of the list based on some conditions. First I want to create one list whit the The Coca-Cola ...
151 views

How can I export definitions of several symbols to a single file?

the problem related to this question What I want to do is to Export definition of several symbol into a single file. The reason I choose ...