How to handle date data for Knn? I'm working on a project about predicting kickstarter project success(classification) and my dataset has many columns that could be used as features such as :
state_changed_at, 
launched_at, 
created_at. 

Now the dataset has these features on unix timestamps. 

Do I need to convert dates to some other format?

Can date data be used as a feature ? 

If so how do I handle them ?   

Do I keep them as a unix timestamp and try to scale/normalize them ?
Can date data be used as a feature?


Yes.


  If so how do I handle them ?


Think about your problem. Why should the date be a reasonable indicator for the success of a startup? Answering this question tells you also in which way you need to transform it.

Most often, when I use some date information for models, I do the following:


Day of the week: integer/one-hot encoding for Monday, Tuesday, ..., Sunday
Month: integer/one-hot encoding for January, February, ..., December
Hour of the day: integer/one-hot encoding for 0, ..., 23
Seconds/minutes/hours/days since XY: Usually normalized or at least scaled in some way