Re: Reading/Manipulating a csv file with columns that have different data types

[Ben Abbott]

> On Apr 21, 2015, at 11:13 AM, frobeniustaco <address@hidden> wrote:
> 
> Hi folks!
> 
> ----------
> 
> First off, here is a small sample of the data I'm working with:
> 
> 1/7/2015,0,Day,39,8346,32,10,5,0
> 1/8/2015,0,Day,39,4204,32,7,3,0
> 1/9/2015,0,Day,39,6848,29,6,6,0
> 
> ----------
> 
> Here's what I want to do with it, once I get it read into Octave:
> 
> Columns 1, 3, and 4:  I'll want to sort by month, shift (there will b 3
> different strings as values) and machine id (also 3 different values).
> 
> Columns 5-8:  I'll want to do some calculations with these:
> 
> ----------
> 
> I have been searching far and wide for a method of getting my data into
> octave in such a way that I can manipulate it as described above.  I have
> been able to at least read it a couple different ways (csvread, csv2cell,
> etc) but if I try to do any arithmetic on columns 5-8 I get errors.
> 
> Anyone have an idea how I can get the data setup so I can reach those
> objectives?   The most frustrating part of all this I have a pretty
> confident vision of how the rest of my script will look but I can't for the
> life of me figure out the upload (which seems like it should just be a few
> lines, at best).
> 
> Thanks!

The short script below converts your csv-file into a matrix of doubles.

csvfile = "test.txt";  
str = strsplit ((fileread (csvfile)), "\n");
n = cellfun (@isempty, str, "uniformoutput", true);
str = str(!n);
str = cellfun (@(s) strsplit (s, {",", "/"}), str, "UniformOutput", false);
r = numel (str);
str = [str{:}];
str = reshape (str, numel (str) / r, r);
# Replace shift text with numbers
str = strrep (str, "Day", "1");
str = strrep (str, "Second", "2");
str = strrep (str, "Night", "3");
# Convert all char data to double
str = cellfun (@str2double, str, "UniformOutput", true);

The result is 

str =

      1      1      1
      7      8      9
   2015   2015   2015
      0      0      0
      1      1      1
     39     39     39
   8346   4204   6848
     32     32     29
     10      7      6
      5      3      6
      0      0      0

Ben