Formatting and plotting downloaded data

Hi.

I have some hourly readings over the course of several months.

The data looks like this in the .txt file:

01/01/2017 00:00
780.70

01/01/2017 01:00
780.71

01/01/2017 02:00
780.74

Note that the time is 24-hr format with the date and time on one row and the reading on the row below. I have tried several methods with varying results to make this data useful including the Import Data tool, which I don't fully understand.

All I want to do is find an acceptable way of using this data to generate a nice looking plot with the date and time clearly visible on the x-axis and the reading on the y-axis.

Thank you.

Answer 1

[Nirav Sharda]

This can be achieved by using Low-Level File I/O functions like fopen,fgetl etc. I am creating a small script that can be used as a reference.

% open the file for reading
f = fopen('filename');
time = {};
values = [];
k = 1;
% The idea is to keep reading lines till the end of file is reached
% The lines are grouped in three line groups: firs line date, second line
% value and blank line to be skipped.
while ~feof(f)
    % read the first line
    line = fgetl(f);
    % add it to the cell-array
    time{k} = line;
    % read the second line containing the value
    line = fgetl(f);
    % add it to the matrix
    values(k) = str2num(line);
    % skip the blank line
    line = fgetl(f);
    k = k + 1;
end
% convert cell-array to datetime array
time = datetime(time,'InputFormat','MM/dd/uuuu HH:mm');
% plotting
plot(time,values)
% close the file
fclose(f)

I hope this helps.