Matlab substring - string

Question

I am trying to get average a specific value in a long string and cannot figure out how to pull a value out of the middle of the string. I would like to pull out the 27 from this and the other strings and add them
2015-10-1,33,27,20,29,24,20,96,85,70,30.51,30.40,30.13,10,9,4,10,6,,T,5,Snow,35
2015-10-1,33,27,20,29,24,20,96,85,70,30.51,30.40,30.13,10,9,4,10,6,,T,5,Snow,35
2015-10-2,37,32,27,32,27,23,92,80,67,30.35,30.31,30.28,10,10,7,7,4,,T,8,Rain-Snow,19
2015-10-3,39,36,32,35,33,29,100,90,79,30.30,30.17,30.11,10,7,0,8,3,,0.21,8,Fog-Rain,13
2015-10-4,40,37,34,38,36,33,100,96,92,30.23,30.19,30.14,2,1,0,6,0,,0.13,8,Fog-Rain,27
2015-10-5,46,38,30,38,34,30,100,91,61,30.19,30.08,29.93,10,7,0,6,2,,T,6,Fog-Rain,23
fid = fopen('MonthlyHistory.html');
for i=1:2
str = fgets(fid);
c = strsplit(str,',');
mean=mean+c;
end
fprintf('Average Daily Temperature: %d\n',mean);

Answer 1

Method 1: use readtable
I'm guessing this is pulled from weather underground? Take your csv file and make sure it is saved with a .csv ending. Then what I would do is:
my_data = readtable('MonthlyHistory.csv');
This reads the whole file into the highly convenient table variable type. Then you can do:
average_daily_temp = my_data.MeanTemperatureF; %or whatever it is called in the table
I find tables are a super convenient way to keep track of tabular data. (plus readtable is pretty good).
Method 2: continue your approach...
fid = fopen('mh2.csv');
str = fgets(fid); % May need to read off a few lines to get to the
str = fgets(fid); % numbers
my_data = []; %initialize an empty array
while(true)
str = fgets(fid); % read off a line
if(str == -1) % if str is -1, which signifies end of file
break; %exit loop
end
ca = strsplit(str,','); % split string into a cell array of strings
my_data(end+1,:) = str2num(ca{3}); % convert the 3rd element to a number and store it
end
fclose(fid);
Now my_data is an array holding the 3rd element of each line.

Answer 2

You can use textscan, you might be able to simplfy your code using this as well, but for a single string, it works like this:
S='2015-10-1,33,27,20,29,24,20,96,85,70,30.51,30.40,30.13,10,9,4,10,6,,T,5,Snow,35'
T=textscan(S,'%s','Delimiter',',')
str2double(T{1}{3}) %// the value we want is the 3rd field