Questions about getting data, files, images etc. from various formats into a form that can be read, tranformed and manipulated by Mathematica

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38
votes
8answers
6k views

How do you convert a string containing a number in C scientific notation to a Mathematica number?

Suppose I have a string containing the C-representation of a floating point number, for example s = "1.23e-5" and I want to convert this to a Mathematica number. ...
65
votes
3answers
6k 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 ...
37
votes
5answers
5k 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 ...
23
votes
3answers
2k views

Reading periodic elements from a large file

I have a large binary data file (big endian) with 100+ million "rows" of 11 elements, combination of floats and integers. This is the format: ...
20
votes
2answers
4k views

How to import all files of a folder at once?

I know how to import one textfile by calling its name filestring = Import["myfile.tex", "Text"]; Then "filestring" is a string with the myfile content. How do ...
21
votes
2answers
1k views

How to build a bvh (a motion capture file format) player in Mathematica?

How to build a bvh player that can be used to visualize human motions in Mathematica? Any idea or sample code would be appreciated. ...
33
votes
4answers
3k views

Importing videos in Mathematica

Mathematica's Import command is purportedly able to import .AVI files. However, I find that many files that I want to import do only result in MMA showing a blank ...
25
votes
3answers
3k views

How to read data file quickly?

I have a tab separated value file with 10 million rows each of which has three tab separated values. The first value is a string, the second an integer, and the third another string. How to read ...
20
votes
4answers
2k views

Is it possible to use Mathematica to record sound and/or vision?

I think the title says it all. I know about ImageCapture which seems to capture stills. Can ImageCapture be made to capture a ...
10
votes
2answers
2k views

Speeding up Import and Export in CSV format

I am handling large numerical data in Mathematica. In smaller problems everything worked fine using Export and Import with the ...
1
vote
1answer
464 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/ ...
25
votes
3answers
2k 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 ...
23
votes
2answers
2k 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 ...
21
votes
6answers
4k views

Cut and paste data from a spreadsheet

I have a set of data points in two columns in a spreadsheet (OpenOffice Calc): I would like to get these into Mathematica in this format: ...
13
votes
3answers
1k 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 ...
7
votes
2answers
878 views

How do I display imported images at actual size?

I know that this is an extremely basic question, but I am having a lot of trouble finding the answer in the documentation. When I import an image (for example, ...
5
votes
1answer
588 views

ReadList can't read from file containing high-precision Reals

I want to read a file which contains seven columns of real numbers. Mathematica seems to have a problem with the high precision I need. My code: ...
13
votes
3answers
7k views

Plot data from txt file?

I have data in file.txt which can be expressed by 20000x11 matrix. I do not want to import all of these data. How can I plot graph of the column 1 & column 4?
22
votes
2answers
3k 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 ...
19
votes
2answers
626 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 ...
16
votes
1answer
968 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 ...
10
votes
3answers
1k 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: ...
7
votes
1answer
421 views

Mathematica 10 doesn't support path containing Chinese characters

Note: This works correctly in version 10.0.2. I tried to import file in Mathematica 10 ( windows 7 system), the path contains some chinese characters. After holding ctrl+shift, and drag the file ...
1
vote
3answers
3k views

Importing multiple files using a for-loop

once again I am stuck solving a seemingly easy problem :( I would like to make a List of tables by importing data from several txt-Files. Importing the data into a table works so far and I am able to ...
26
votes
1answer
2k 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 ...
9
votes
1answer
587 views

Google Image Search in Notebook?

How can I use Google's image API to custom search for images and import them all?
16
votes
1answer
971 views

Slow import of multigigabyte TIF image stacks

Update 6: After contacting Wolfram Technical Support, I was advised that the frame-to-frame import timing variability can be eliminated by reading in the frame stack from frame to frame with the ...
14
votes
2answers
1k views

Dealing with large files

I have a *.dat file in which the contents are basically one giant list: {1,2,3,4} {5,6,7,8} {9,10,11,12} and so on. I'd like to read in the first 500 members { ...
10
votes
2answers
3k views

How to get Matlab data imported with the same dimensions?

I have some Matlab image data with the following dimensions (output is from Matlab): >> size(im) ans = 86 86 3 45 The data imports just fine ...
12
votes
3answers
1k views

How can I transfer mathematical expressions between Mathematica and Maple?

Is there a simple way to copy mathematical expressions between Mathematica and Maple (or at least in one direction)? I mean only expressions built from numbers and predefined mathematical functions, ...
7
votes
2answers
2k 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 ...
3
votes
2answers
639 views

video image recognition [closed]

Has anybody experience with video and image recognition? I've made a video of two teams playing soccer. Now I would like to translate each soccer-player to a (x,y) coordinate and follow them during ...
1
vote
3answers
239 views

How to import files with headers?

R has excellent header supports such as read.table with header options. I don't want to mess up with text-processing or stream-processing. I am looking for a similar tool as in R because it saves a ...
13
votes
4answers
1k views

Importing HDF5 with compound data

I am looking to Import HDF5 data with compound data. It appears, at least from what I read, that Mathematica 8.0.4 (and previous versions) does not support reading ...
12
votes
6answers
2k 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 ...
7
votes
1answer
3k 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?
9
votes
2answers
812 views

Import tweets from Twitter

Robert Raguet-Schofield in the Mathematica Blog introduced a way to import tweets from Twitter into Mathematica. I attempted to use this method. I started with this line of code: ...
5
votes
1answer
574 views

Open data file from CDFPlayer?

Using a CDF program running in CDF Player, is it possible to use a system dialog box, or even just an Import statement such as Import["*.CSV"], to import data from a text or comma separated file on a ...
8
votes
4answers
848 views

Import values from tab separated file, change decimal point?

I have files that look like this: ...
3
votes
1answer
320 views

Exporting lists to files

I am trying to write a program which will generate a list of objects and then exports it in a separate file and clears its memory. As an example I tried the following ...
1
vote
1answer
741 views

Import Excel sheet into 3D array?

I have an excel spreadsheet that I would like to plot in a 3D graph using mathematica. The X and Y values are the location of the cell, and the Z value is the number of the scale. How can I import ...
16
votes
1answer
483 views

Gravatars/identicons with Mathematica

The default avatar/identicon is based on an MD5 hash of your e-mail address. With some e-mail providers (e.g., GMail) the address gmailuser+foo@gmail.com is still ...
18
votes
4answers
1k views

How to efficiently import videos

I need to do frame-by-frame analysis of videos. I can import the video files I need, but each file is too large to import at once. I can use the ...
8
votes
2answers
318 views

AJAX-style HTTP calls triggered by a variable change

I'm trying to create a dynamic InputField that would autocomplete the address as I type it into the field, by calling Google Maps' GeoCoding API on every change of ...
9
votes
2answers
915 views

Exporting data from Excel into Mathematica using clipboard

I know that it's possible to import Excel data into Mathematica using the Import command, as we can see in this post. But some times, I need just to do some fast ...
13
votes
2answers
564 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 ...
7
votes
1answer
241 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 ...
18
votes
1answer
676 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 ...
15
votes
1answer
320 views

Why does ImportString[“1c”, “Table”] eat the letter c?

I have some whitespace-separated matrix data that I read with Import[..., "Table"]. The data contained mixed strings and numbers (the strings are for row and ...
6
votes
1answer
802 views

Stream CSV files

Ram limitations make import impractical for large CSV files. Is it possible to Stream CSV correctly? ...