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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12
votes
3answers
545 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. ...
5
votes
2answers
1k 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. ...
0
votes
2answers
178 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 ...
6
votes
3answers
2k 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 ...
1
vote
1answer
622 views

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

I have a data set. ...
1
vote
1answer
156 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 ...
1
vote
1answer
180 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 ...
3
votes
1answer
130 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 ...
0
votes
2answers
209 views
3
votes
1answer
233 views

DistributionFitTest with WeightedData?

My problem is related to statistical testing with weighted data. I have a data sample and I assume that a part of the data follows a specific distribution (Pareto). So I fit my data to a distribution ...
0
votes
1answer
132 views

Choosing range when plotting data from array

I have loaded data from a CSV file which i want to plot in a BarChart but i only wish to plot 0:100 instead of the entire ...
2
votes
0answers
316 views

Lazy evaluation/loading of parts of an expression

Is it possible to have an expression x such that its elements are only evaluated when they are individually accessed, for example when evaluating statements like ...
0
votes
2answers
831 views

How to generate a random data set with determined expected value and variance? [closed]

Recently I am doing my math homework and there is a question asking me to Come up with a dataset X that has at least 10 distinct numbers in it such that Expect[X] = 3.7, and Var[X] = 2.1. Actually I ...
2
votes
1answer
194 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
27
votes
5answers
6k views

How to perform a multi-peak fitting?

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3). The ...
0
votes
1answer
131 views

Column specific data inputs

My data is in the form of 6 columns in a notepad file. I want to import, only from a specific column,say, the third column into Mathematica in the form of a list, i.e., i want commas to be placed ...
0
votes
2answers
219 views

Visualizing multi-state lattice from a data set

Is there any way to make Mathematica visualize a multistate square lattice? That is, I have a data set from a simulation that is x coloumns wide and y rows tall (just a simple .dat file), where each ...
3
votes
0answers
210 views

Exporting Specific Cells of Many Workbooks into One using Mathematica

I currently have a large number of detailed files from which I would like to extract certain cells' information to make an Archive spreadsheet. There are approximately 9 parameters of each ...
2
votes
1answer
2k views

Using NonlinearModelFit to fit data with errors

Assume we have some data of measurements SeedRandom[9]; data = Table[{i,2*(1 + 5*RandomReal[])*Exp[-0.01*(1 + RandomReal[])*i]}, {i, {0, 100, 200, 400, 700}}]; ...
2
votes
2answers
303 views

Importing LTSpice data into mathematica

I am working with LTSpice (Discret electrical circuit ( Spice) simulator). I would like to import LTSpice ouput data into mathematica for processing and plots. An example of a file can be found here ...
0
votes
0answers
365 views

Performance in parameter estimation from ParametricNDSolve using varied initial conditions

I have 250 data points from a timecourse exeriment in a list, with columns specifying (1) time, (2-4) initial conditions, (5) absorbance reading. I want to fit 4 parameters (k1, k2, k3, k4) in a DAE ...
3
votes
1answer
152 views

Saving and Reading data across computers

I DumpSaved some data from my home laptop, uploaded it onto google drive and now I am trying to open it at my school computer but I am getting errors, even though the data is in the correct directory. ...
2
votes
0answers
114 views

Significant platform-dependent efficiency when importing data?

I'm curious, as I understand that answer this way: If you are using a Linux derivative or something like cygwin on Windows, then this is an efficient solution for reading only the third field ...
1
vote
2answers
236 views

Efficient Data Entry / Manipulation with Many Datasets

I currently have a simple task of graphing many different datasets (26 here, with many different instances where I'll need to do, say, 26 different ones from the same template). I'm trying to ...
2
votes
2answers
1k views

Importing several huge files with headers & footers

having here several files in ASCII format http://ge.tt/91rv0Jf/v/0 I want to import, while removing headers and footers and then join the several lists. ...
14
votes
3answers
560 views

How to Import random elements of huge data files

I am calculating huge data files with an external program. I would like then to import the data into Mathematica for analysis. The files are 2 columns and up to many millions of rows. So for ...
1
vote
1answer
72 views

Substituting Data from File

I have sets of Diff. Eq. that I'd like to solve symbolically, then substitute in numerical values for some of the symbols. I'd like to store the value for each symbol in a file, e.g., an excel ...
1
vote
1answer
168 views

Table/Tree of values

My question: Is there a way to create a tree of values? Something like the output of the command TreeForm, but with values in the nodes? Why do I want this? I'm trying to do a complete program to ...
12
votes
6answers
1k views

Determine the Number of Lines in a Text File

I have looked and looked but I do not see a simple efficient way to get MMA to return the number of lines in a text file? I thought about reading the file until it returned the EOF marker, but that ...
7
votes
2answers
115 views

How can I recover a graph from a graphical output in a notebook after resetting the kernel?

I have an old Mathematica notebook with an output for a graph structure $G$ I would like to recover. However, the routine for building up the graph is stochastic, so I can't simply rerun the code. ...
1
vote
2answers
164 views

Request help for reading text data files with headers and 2 sections

I just started with Mathematica. I need it for many purposes, but the important one is to read a text data file and extract column values as variables. I have successfully tested the tab delimited ...
1
vote
0answers
533 views

Doing local FFT on huge 3D vector data cell mesh and visualizing it spatially?

Simulation type: I'm running a simulation with the OOMMF micromagnetics package http://math.nist.gov/oommf/ where are magnet is represented by a mesh of 3 million cells, it gets excited by a ...
6
votes
3answers
271 views

Storing data in the Notebook in readable form

The common problem in my theretical work is a need to import some experimental data to work with. This means that my notebook depends on some external files which makes it difficult to share it with ...
15
votes
4answers
1k views

Plotting data points: Optimizing size and visuals

The following problem is one that may have showed up to you while plotting a large data collection. Suppose you have a data set of say 1 million points. ...
1
vote
1answer
238 views

Automating sequential import of data from web

I am trying to import data from multiple web pages hosted by a single online source. The data is posted by the source as one data set per web page for each week of the year. I would like to import the ...
1
vote
2answers
294 views

Running out of memory when filtering a large data set

My goal is to read list0.dat, filter the data with a function f, and then write the transformed data to ...
4
votes
1answer
3k views

Transform 3D data into 2D color map like Matlab's surf/imagesc

I have a bunch of 3D data (x, y coordinates and values) which is generated in Matlab and I need to render them in a 2D color map with certain axis ranges. Here are the Matlab code and the generated ...
4
votes
2answers
725 views

Check Google PageRank for a given URL

Does anyone know how to write a Mathematica function that returns the Google PageRank of a given URL? I found a tutorial for achieving this in a bash script here, but I have no idea how to port this ...
3
votes
1answer
561 views

NonlinearModelFit returning nonsense for very simple data

In fitting the following data, if I first log transform the y-values and use LinearModelFit I get a set of parameters that fits the data: ...
3
votes
2answers
815 views

How can I control the number format of exported data?

I'm having issues while exporting a tables of numerical values to "*.dat" data files. Here's the thing, sometimes when I export a table, I get more decimals on some random values. The problem is that ...
1
vote
2answers
3k views

Export plot data in Mathematica [duplicate]

How can I export data, which is plotted using something such as: Plot[Γ[x]/(1.6*10^(-19)), {x, 0.1, 1.2}] into a .txt file in Mathematica?
-2
votes
1answer
372 views

Non-regular grid data

I have issue with non-regulary spaced data. I have set of 3 numbers {x, y, z} in my list. ...
5
votes
1answer
208 views

WolframAlpha Selective SubPod Content

I am sending queries to Wolfram | Alpha from Mathematica V9 and and importing the results back into Mathematica, but I am running into a challenge in formatting the request. Specifically, I would like ...
5
votes
2answers
734 views

ListContourPlot interpolation screws up on concave set of data

I want to create ListContourPlots for sets of Data (from a physics simulation) given as Triplets {x, y, f(x, y)}. Certain parameter regions in the x-y-plane are ...
2
votes
1answer
612 views

Importing data sets from plain-text files and performing operations on them

I am working with a lot of daily weather files in the txt format. I need to calculate a daily quantity from each of them, e.g., daily light intensity, which ...
3
votes
1answer
616 views

Read and filter a text file without importing

I have a large text file of a million sections. Each section contains A lines of header and B lines of numeric data. I want to read the first and last line of B from each section (to have a list of 2 ...
9
votes
3answers
991 views

Approximately Fit Data Without FindFit

I have some noisy data, and I'd like to analyze the derivative of the function the data approximately matches. Interpolation is normally great, but doesn't work ...
2
votes
1answer
137 views

Plot[] breaks behavior of custom data handling function - Recursion

I am working on a utility to analyze a set of data. I want to process the data with a sliding window, in such a way that there is an output associated with each sample of data. To start, I have a ...
19
votes
4answers
2k views

How to integrate functions of linearly interpolated data?

At first, consider integration of pure InterpolatingFunction. Importing some data (works in v.9, for earlier versions one can use this link to download zipped ...
1
vote
0answers
100 views

ReadList and multiple access of the same file

I have a file containing a large amount of data which can be processed independently. In order to process all data in a reasonable amount of time I distribute the jobs on three different machines. ...