Date and time as variables

Hi guys, this is my first post here!
I am a student from Italy and for my thesis I'm working with Knime.

I'm studying to become a laboratory technician and I'd like to do some analyzes about laboratory data.
Well, I've prepared an Excel CSV with 126000 rows, the columns are:

Exams - Exam result - Age - Gender - Exam Date - Exam Time

Now, I have to see the relationship there may be between the exam results and exam dates, and exam results and exam times but there is a problem: I can not put exam dates and exam results as a variables.
I've tried using String to Data/Time node but it didn't resolve my problem.
My data format is dd/MM/yy

So guys, how can I put exam dates and exam results on the x or y axis?


P.s. sorry for my bad English, for me it is unusual to speak of these things in another language.

The same problem described under the link:

Thanks for your post!
Now I'm out so can not try but I'll do it early as possible.

I have another question, if I have a column with date and time together (25/08/2016 13:59:34) can I use that method to transform all two dates?

I'm not quiet sure that I understood you correctly.

My previous post contains link to conversation about lack of posibility to use date/time fields as flow variables.

I do not know what do you want to achive. 

The second question: Yes you can transform string 25/08/2016 13:59:34 to date - String to DateTime with date format as follows "dd/MM/yyyy HH:mm:ss"

Thanks for your answer.
I know, I'm sorry for my bad language.

I'll try again: I need on the x axis date and time (together or split).
Is it possible?


This sounds like a misunderstanding of what a variable in a regression analysis and what a varaible in KNIME is.

The data in different columns in a table are your dependent and independent variables in an analysis. 

Knime flow variables are to control the workflow, and is in general not the variables" in a regression analysis. 

As for displaying time series data, as Iris pointed out in jFreeChart Line Chart node can plot data against a date or date time series as the x-axis.

If your exam dates are meant to be categorical varaibles, that is, each date independent from another and order between dates is not meaningful, then just use them as strings in a regression node. Similarly do the same with time. If you need the date as in result = alpha beta x date + noise where date is meant to be a continuous variable, then you will need to change it from datetime or string to a double or integer. ie,, result = alpha + beta x (date - start date) + noise to use one of the regression nodes.

Hope that helps.


I do not find the jFreeChart Line Chart, where I could find her?

You need to install the jfreechart extension 

ok, thanks, I will try.
I apologize if I write occasionally, I have problems with the Internet line.
I will try to explain as best as possible:


I have laboratory data classified by type of examination (red blood cells , 
white blood cells , blood sugar and so on. ).
Each result of the laboratory has a precise time ( some are repeated ), 
I would like to organize this data in order to see regressions and other things such as the application 
of Bayes theorem.
The problem is that I do not know how to " prepare " the data for examination by KNIME .
I created using excel columns Exams ( type ) - Exam result - Age - Gender - Exam Dates - Exam Time .

They are all connected to each other of course .

Dear Sandorkan,

please open a new thread for your question, as it is not related to the topic.

Best regards, Iris

I apologize if I keep still here but the main problem is to put the time on the x axis .
The file reader has time as a string, and the result as a number.
Then use the node "String To Date / Time" for the time .
After I connect "String To Date / Time" node with JfreeChartLine, I set the time on the X but when I run it appears this error: "Execute failed: You are attempting to add an observation for the time period Thu Jan 01 08:06:00 CET 1970 but the series already contains an observation for that time period. Duplicates are not permitted.  Try using the addOrUpdate() method."

What am I doing wrong?

1 Jan 1970 is the start of time in java, so unless you do have data from 1st Jan 1970, it looks like there is a date parsing error.

Can you give a few lines of the data? it may help to see. 



In the Csv files there are the dates of birth of patients ( prior to 1970, of course) but I skip the selected item . It could be the problem?

This is the list of results (Risultato) of a single laboratory test , in one day.
I would put individual times on the X axis and see the pattern of results in a day.
After adding the String To Date / Time node add the JFreeChart Line and appears that message .

Could someone help me please? :)

sorry, I don't see the pic in the link. Trying gives "This image or video has been moved or deleted"


it maybe easier jus to create a table (the grid between the image and the omega sumbol on the top line of the tools) for the comment area and paste in the data