plot not displaying figure

i have table which has datetime and sub_metering_1 as two variables on table. I wrote code to plot the figure but it is not showing

if (data_useful.DateTime.Hour==8)
   figure()
   plot(DateTime, Sub_metering_1)
end

[dpb]

Your "if" is not getting executed -- IF is True iff all elements of the logical expression are true -- and you undoubtedly have data in the table that are not in the eighth hour as well as some that are.

It's not clear for sure what you do intend, but

is8=(data_useful.DateTime.Hour==8);         % logical addressing for Hour==8
if any(is8)                                 % will match if are any data at Hour==8
  figure()
  plot(data_useful.DateTime(is8), data_useful.Sub_metering_1(is8))  % plot the subset of data
end

While the above will (probably) work to do the one specific thing, it's generally bad practice to bury "magic" constants like the 8 above in code; use variables instead. Then you will be able to change the wanted hour to be plotted simply by changing some data, perhaps tying it to user input or an argument in a function even, without having to change the code itself.

[Ram Basnet]

isa==(data1.DateTime.Hour==8)

if any(isa)

meter_readings_cluster_few = data1.Sub_metering_1;

dates_table_few= data1.DateTime

end

plot(dates_table_few, meter_readings_cluster_few)

Answer 1

[Saravanakumar Chandrasekaran]

You are trying to a logical check for data_useful.DateTime.Hour==8. so at all times it is getting failed.

in the suggestion provided by dpb, you have wrongly included ==

i.e., the line should be

isa = (data1.DateTime.Hour==8)

i hope if u correct the above line ,it will work.