CODEWITHSUNDEEP
matlabfunctiondatetimeplot
N.E.R.D
N.E.R.D

Reputation: 5

matlab plot(x,y) of different data type

i got data (2945 * 3) of different types imported as cell array. 1st column data type has been imported as text (time e.g 1/1/1990), whereas the 2nd and 3rd columns are numbers.

so far i used cell2mat to convert to double both the 2nd and 3rd columns. Thus plot(y) works {y being either the 2nd or 3rd column data} , however i am wondering how i can handle the text data type from my 1st column in an attempt to use plot(x,y).

Any idea would be appreciated. cheers

    --------sample.csv-------------
   Date        LAST       Rt
   1/27/2018    20       0.234556
   1/26/2019    20.05   0.184556
   1/23/2040    20.1    0.134556
   1/22/1990    20.15   0.084556
   1/21/1991    20.2    0.034556
   1/20/1993    20.25   -0.015444
   1/19/1998    20.3    -0.065444
   1/16/2050    20.35   -0.115444
   1/15/2030    20.4    -0.165444

--------cell array appearance------------
      1          |    2     |  3
1|   '1/27/2018'   20        0.234556
2|  '1/26/2019'    20.05     0.184556
3|  '1/23/2040'    20.1      0.134556
4|  '1/22/1990'    20.15     0.084556
5|  '1/21/1991'    20.2      0.034556
6|  '1/20/1993'    20.25     -0.015444
7|  '1/19/1998'    20.3      -0.065444
8|  '1/16/2050'    20.35     -0.115444
9|  '1/15/2030'    20.4      -0.165444

Upvotes: 0

Views: 259

Answers (3)

am304
am304

Reputation: 13876

You could also use datenum to convert the text to a serial date number (copied from Octave command line):

>> test
test =
{
  [1,1] = 1/1/2000
  [1,2] = 1/2/2001
  [1,3] = 10/2/2001
  [1,4] = 10/3/2001
  [1,5] = 10/3/2005
}
>> x_dates = cellfun('datenum',test(:,1))
x_dates =

   730486   730853   731126   731127   732588
>> y = rand(size(x_dates));
>> plot(x_dates,y)
>> datetick('x','dd/mm/yyyy')

Update:

It looks like cellfun requires a function handle in MATLAB, so you probably need to do something like:

x_dates = cellfun(@datenum,test(:,1))

Upvotes: 1

jack
jack

Reputation: 106

You can create a new matrix with usable data (or rewrite your current one) by looping through your matrix(:,1) to convert the strings using the cellfun function.

Or just to plot:

plot(cellfun(@(x)str2double(x), Measures(:,i)))

where i = 1: length(matrix)

Upvotes: 0

Ander Biguri
Ander Biguri

Reputation: 35525

You could use XTick and XTickLabel. The former will set up where and how many ticks you want in your X axis (I guess that you'd want one for each X data, but you also may want to go jumping 10 by 10). The second will set the labels in those tick positions. If the Labels are less than the ticks, they will repeat, so careful with that.

Let me illustrate with an example:

x = [0 1 2 3];
y = [2 0 1 1];
plot (x, y);

yourstrings={'Banana', 'T', 'Potato', '45'};
set(gca,'XTick',x(1):x(end))
set(gca,'XTickLabel',yourstrings)

enter image description here

A second option would be to use text. you could put text wherever you like in the plot. Let me illustrate again. Of course I don't meant to put it "nice", but if you/d like, you could play with offsetting the positions of the texts and so on in order to get a more "beautiful" plot.

x = [0 1 2 3];
y = [2 0 1 1];
plot (x, y);

yourstrings={'Banana', 'T', 'Potato', '45'};
for ii=1:length(yourstrings)
    text(x(ii),y(ii),yourstrings{ii})
end

enter image description here

Upvotes: 1

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