How to determine the date of the first channel entry point | MATLAB | Forum

Avatar

Please consider registering
Guest

sp_LogInOut Log In sp_Registration Register

Register | Lost password?
Advanced Search

— Forum Scope —






— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

sp_Feed sp_TopicIcon
How to determine the date of the first channel entry point
No permission to create posts
January 16, 2018
2:55 pm
Avatar
turgo

Gold
Members
Forum Posts: 70
Member Since:
June 16, 2013
sp_UserOfflineSmall Offline

I'm trying to determine the date of the first channel entry point.  This would seem a simple exercise, but there are problems.  For example, downloading the channel yield a 500 mb file which is impossible to open.  Using thingspeak read with a broad range of dates yields only the ending points.  If the dates are both prior to the channel start, an error is generated.  What do I do?

 

It would be really helpful for thingspeak read to have the ability to return points by index value.

January 16, 2018
5:52 pm
Avatar
Vinod

MathWorks
Members
Forum Posts: 206
Member Since:
May 1, 2016
sp_UserOfflineSmall Offline

If have the file on a Linux computer, you can use the head command. If you are on Windows, you will need to open up a powershell and execute

get-content c:\path_to_file\your_file_name -totalcount 10

to get the first 10 lines.

Out of curiosity, of this 500MB of data how much of it is critical to you and how do you use it?

January 16, 2018
7:02 pm
Avatar
turgo

Gold
Members
Forum Posts: 70
Member Since:
June 16, 2013
sp_UserOfflineSmall Offline

I use the data in realtime as a gage.  Rapid update is important.  However, I don't need this kind of resolution in the historical data, hence my other threads about consolidating my data.  Is there a unix shell command that will work on the mac OS?

January 16, 2018
7:30 pm
Avatar
Vinod

MathWorks
Members
Forum Posts: 206
Member Since:
May 1, 2016
sp_UserOfflineSmall Offline

The head command should work on the Mac. Try

head -n 10 filename.csv

January 20, 2018
1:29 am
Avatar
turgo

Gold
Members
Forum Posts: 70
Member Since:
June 16, 2013
sp_UserOfflineSmall Offline

I found another way.  First, start downloading the entire channel; then cancel the download; finally open the small file containing the first points.

Forum Timezone: America/New_York

Most Users Ever Online: 114

Currently Online:
21 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

rw950431: 261

Vinod: 196

piajola: 85

turgo: 70

vespapierre: 63

Adarsh_Murthy: 62

Member Stats:

Guest Posters: 1

Members: 5703

Moderators: 0

Admins: 2

Forum Stats:

Groups: 4

Forums: 17

Topics: 1313

Posts: 4565

Newest Members:

terranceqh2, DianeEmids, Alanawaype, uqovitay, ufijifode, manish01

Administrators: Hans: 387, lee: 457