Questions about getting data, files, images etc. from various formats into a form that can be read, tranformed and manipulated by Mathematica
4
votes
1answer
564 views
When do I use Mathematica, when do I use Gephi, and how do I use them together?
Mathematica has great operations for analyzing graphs but when the graphs are a bit bigger, Gephi seems to be more efficient (at least on my computer) at drawing and analyzing, i.e. visualizing the ...
6
votes
2answers
366 views
How can I open an Excel file and modify it in Mathematica?
I wanted to ask how can I view an Excel file from a Mathematica notebook and modify it.
I have seen a similar question, Open Excel file with Mathematica, but the answer involves .NET. Is there any ...
15
votes
1answer
436 views
How to export and import Graphs with additional data?
I'm trying to export and then later import graphs with additional data added such as VertexLabels and EdgeLabels. When I export ...
0
votes
0answers
135 views
Importing a Matlab-generated .SET file with embedded .BDF [closed]
I asked this Q on stackoverflow (and also a couple of colleagues) but still no answer
http://stackoverflow.com/questions/11142962/extracting-bdf-from-matlab-generated-set-file
Anyone know how to ...
1
vote
1answer
207 views
Interpolate specific columns of data
I have a txt file with 3 columns of data:
x y1 y2
How do I import the file then create 2 functions, one interpolated with {x,y1} values and the other interpolated with {x,y2} values?
This ...
2
votes
0answers
218 views
Can not Import PDF
I try to import PDF and extract text from it
Import["D:\\Vegetarian MS.pdf", {"PDF", "Plaintext"}]
but with some files I have a problem like this
...
8
votes
2answers
328 views
How can I animate a set of points imported from file?
I have an external program which generates a set of data - X points at the time t1, X points at the time t2 and so on. These points are stored in CSV file and I can change the format if necessary.
...
6
votes
2answers
205 views
How to process binary-encoded data without writing to file and importing?
I am consuming a webservice through NETLink that returns data directly in the response as a gzipped csv file.
I can successfully process the data like this:
...
4
votes
1answer
806 views
Importing CSV financial data in Mathematica
I am trying to import a CSV file in Mathematica 8 with the aim of charting it with the TradingChart command. This is what I have done :
...
4
votes
1answer
363 views
Efficiently exporting many images as a video
I have many .gif images and I would like to export them as a single video file (I prefer .mov, but any video format is fine). But what if I have several tens of megabytes of .gif images? Is it ...
12
votes
2answers
314 views
How to monitor the progress of Read?
I use
f = OpenRead["largefile.m"]
x = Read[f];
Close[f];
to read in a Mathematica expression from a large file largefile.m ...
8
votes
2answers
163 views
5
votes
2answers
225 views
How to remove an expression from a file?
To read in expressions from a file, one can do ReadList[file, Expression, 3]. How to do the opposite, i.e. remove a number of expressions from a file, modifying ...
13
votes
2answers
689 views
How to save all data in all variables so that loading it is fast?
I've got this CSV file I've imported that has tens of millions of lines in it. It takes around 20 minutes to import. I've been working with it for a while and have the processed data spread out in a ...
3
votes
3answers
222 views
Support for Compressed Sparse Column sparse matrix representation
Is there native support for Compressed Sparse Column (CSC) format for sparse matrices, like importing and manipulating them?
15
votes
1answer
324 views
When importing GIF animation, how to find the correct list of “DisplayDurations”?
When importing GIF animations with variable frame durations, the settings for "DisplayDurations" are not recovered correctly. As an example, I'm using the movie from this earlier question:
Here I'm ...
13
votes
3answers
447 views
How to scrape the headlines from New York Times and Wall Street Journal?
How to scrape headlines from New York Times, Wall Street Journal main pages to create datasets similar to this service?
Importing HTML from nyt.com (HTML4) results in a ...
6
votes
3answers
186 views
How can I read in specific information from a TeX-file?
I have several TeX-files and they contain information of the form
...
7
votes
1answer
107 views
Using Differences on data: trouble with floats and doubles
Consider the following data set (after I have run FullForm), which is imported from a file (stored typically as 10.040):
...
7
votes
1answer
684 views
Import DCD (CHARMM/NAMD binary trajectory) file
How can one import the coordinates stored in a binary CHARMM/NAMD DCD file?
This is the structure of the file:
...
5
votes
2answers
254 views
11
votes
1answer
695 views
Web Browsing Automation with Mathematica
I want to build a bot to automate web browsing, this mean something like:
filling forms
press "submit" buttons
find certain text inside pages
and so on...
How can I do this with Mathematica?
The ...
2
votes
1answer
200 views
How to solve issue with exporting / importing data to and from Excel
Background ( simplified ):
When I export data to Excel like
...
26
votes
5answers
2k views
How can I extract data points from a black and white image?
Consider the following graph (source):
Is there any way to extract the data points from this image in a semi-automatic way? I have seen, and tried the methods suggested in this question, but they ...
4
votes
1answer
558 views
Difficulties with Importing PDFs in Mathematica
I am trying to import a group of PDFs that I have downloaded (it is in the realm of 1,000+). They are a group of doctoral dissertations that I'm trying to automatically extract bibliographic ...
10
votes
1answer
157 views
Exporting and reimporting a list of lists changes the dimensions
Could anyone explain to me what in the world is going on here and please help me in reading in dummy.dat properly?
...
12
votes
2answers
1k views
Importing a large Excel file
I'm trying to import a simple Excel file containing 94,000 rows and 52 columns of various types, mostly Reals. It's a 38-MB file. I get this super helpful error ...
3
votes
1answer
419 views
Stream CSV files
Ram limitations make import impractical for large CSV files. Is it possible to Stream CSV correctly?
...
19
votes
2answers
750 views
Extracting values from nested rules in JSON data
I have been using Mathematica to analyse some data from the StackExchange API. It is conveniently available in JSON form, which Mathematica interprets as replacement rules. However, some of the rules ...
6
votes
1answer
1k views
How to extract sample values from an imported WAV file?
Suppose I read a file with
B = Import["something.wav"]
Now how can I obtain a list of sample values?
14
votes
2answers
262 views
How to load thumbnail, not image?
Is there any way to import only the thumbnail of an image instead of the full image? I frequently work with lots of images and it would be nice if the contents of a directory could be quickly ...
3
votes
2answers
2k views
Importing from Excel
I'm trying to import a matrix from Excel to Mathematica. My code is:
Import["desktop/stproj.xls", "xls", data, 1]
The output is some weird stuff about population ...
8
votes
1answer
284 views
How to properly DumpSave & Get Global`s symbols inside packages while not touching Global context?
For efficiency reasons I prefer to use DumpSave instead of Save.
For ease of access I prefer to save symbols in ...
6
votes
3answers
172 views
Organizing similar datasets using DownValues instead of Contexts
In his answer to this question, Leonid helped me find a way to programmatically generate contexts for holding sets of symbols with the same names. Perhaps a simpler way is to use ...
7
votes
1answer
113 views
Organizing similar datasets using Contexts or otherwise
I often import several long time series to analyze something about a city. When I have multiple cities, I use contexts. As a simple example,
...
15
votes
1answer
290 views
Importing Zip files
Mathematica can import zipped files automatically, but when the content of the zip file it's another zipped file, I just get the list of files in the second zip:
...
3
votes
1answer
223 views
Mathematica Import functions fails for data download from website
I am trying to download some data from a website that uses "java enabling" to tell me that I cannot download the data. Using
Import[ "website...", "Data"]
I get
...
9
votes
6answers
856 views
How do you skip missing data values in a data file?
In scanning through a simple imported file of weather station data, some dates have missing data.
What is a test to use to check whether a datum is valid? I tried ...
15
votes
1answer
699 views
How to manipulate web pages on Mathematica?
I wanted to input some data on this page through Mathematica:
http://www.fundamentus.com.br/buscaavancada.php
Then I would press the "buscar" button also through mathematica coding and get the ...
11
votes
3answers
322 views
Data of badly formatted file
Similar as in this question, I have to read in data from a file (exampleFile.txt) which is not so well formatted.
Unfortunately, I cannot find a solution by myself. Since it is a bit complicated to ...
11
votes
1answer
317 views
Release the web camera after using CurrentImage[]
CurrentImage[] will capture an image from the webcam. It is even possible to create a live video in the notebook using
...
41
votes
3answers
2k views
Recovering data points from an image
Unfortunately, some data can only be obtained in picture form (Japanese publications anyone?). Since this cannot be worked with, it has to be converted to a dataset that can; I was wondering whether ...
4
votes
3answers
246 views
Plotting data with exponentials
I have some data with 19000 sublists such as :
{" 7.9080000e+01 1.9283193e+04"}
Where the first number is the value for variable ...
3
votes
2answers
829 views
Importing .txt or .csv financial data
I am trying to import some financial data exported from Excel. You can find the relevant file here : Text File or CSV File
This is what the data looks like in Excel :
Using the following code to ...
9
votes
3answers
500 views
Is it possible to import dates and times directly as AbsoluteTime and by pass DateLists?
Date and time calculations are quite slow so I am exploring ways to minimize the number of calculations performed. As an example:
...
1
vote
1answer
329 views
How can I speed up image importing? [closed]
The following examples show how slow it is to load a simple GIF. Can anything be done to make it faster?
System #1: Mathematica 8.0.1.0, HP notebook, Win7 64Bit, 2 x 2.4Ghz Intel Core i5, 2GB RAM, w/ ...
14
votes
2answers
305 views
Is Compress[] compatible between different Mathematica versions?
Compress[] was introduced in version 6 of Mathematica. It gives a compressed version of expressions represented as a string of ASCII characters. It preserves more ...
12
votes
2answers
353 views
How to develop an Import/Export converter for Compress[]ed data?
Mathematica has a cross platform data exchange format, WDX. Unfortunately importing or exporting large data from/to WDX is very slow. Using MX files is very fast, but they are not compatible across ...
6
votes
3answers
332 views
Efficient image Import
I have several sets of 20 images I need to import.
Each time they have different categories.
"Name"<>"Cat"<>"No"
Electric B 1 for example.
I need to create lists that contain the images ...
6
votes
1answer
216 views
Operations on online files via public URL access
I need M. to access an online public directory via some URL (fake in this case)
http://example.com/images
and perform operations similar to those M. can do on OS directories and files. Examples:
...
