How do I get MATLAB to use first set of data from csv Excel sheet I have?

Hello,

I'm doing some practice in MATLAB importing data from an Excel csv file. I did an example where I created two vectors for time and population density and then I plotted them. I tried doing the same exact thing, but rather than creating the vectors by hand e.g., time = [2000:1:2016]; population = [blah, blah, .... blah]; I have them as colomns of cells in Excel. I imported the csv file into MATLAB by doing filename = 'P_D.csv'; data = csvread('P_D.csv', INSERT SOMETHING HERE !?). The !? is where I'm stuck. When I plot the data, and compared the graphs, I noticed that the Excel method was messed up. MATLAB is skipping one set of data points i.e., rather than starting at Time = 2000 and population density = some #, MATLAB is doing Time = 2001, and population density = some # attached to 2001. I don't want to skip the year 2000's data points. How do I fix this? I'll include the M-file and excel file for you guys.

Thank You!

Time = [2000:1:2016];
t = Time;
Population_Density = [100, 150, 120, 200, 220, 225, 190, 100, 300, 280, 301, 200, 110, 245, 450, 199, 200];
p_d = Population_Density;

figure(1)
plot(t, p_d, 'b-o', 'linewidth', 2)
title('Bacterial Population Density [2000,2016]')
xlabel('Time')
ylabel('Population Density cells/ml')
legend('Done Completely in MATLAB', 'location', 'northwest')
grid on;

filename = 'P_D.csv';
data = csvread('P_D.csv',1); % MATLAB won't start with data at the year 2000 and the population density at t = 2000; ?
TIME = data(:,2);            % changing to 0 won't work, so I don't know what to do, the best I can do is start at 2001.
POP_DEN = data(:,4);

figure(2)
plot(TIME, POP_DEN, 'k-o', 'linewidth', 2)
title('Bacterial Population Density [2000,2016]')
xlabel('Time')
ylabel('Population Density cells/ml')
legend('Done with Excel sheet', 'location', 'northwest')
grid on;

[per isakson]

What makes you think there is a data point 2000,100 in the csv-file?

[Star Strider]

It exists using xlsread, although not using csvread.

[Nathan Nguyen]

per isakson,

I know that the data point (2000, 100) doesn't exist when I do filename = 'P_D.csv' and data = csvread('P_D.csv',1) , which is why I'm asking for help. I don't know why it's not included.

Answer 1

[Walter Roberson]

csvread() cannot handle text, except that you can tell it to skip leading rows and/or leading columns. So you can tell csvread() to skip the first row, which you are doing, but when you do so you are skipping the row that has the 2000 100 values.

You need to use xlsread() or readtable() or write your own reading routine, such as using textscan() or more low-level routines.

[Nathan Nguyen]

I don't have much expierence with writing my own reading routine in MATLAB, but I like to think that it's not too difficult? + There's most definetely documentation on how to do such things.

Thank you!