Raw Message

Message-ID: <8B435C9568170B469AE31E8891E8CC4F3DBB763F@ESINO.regionemarche.intra>
Date: 2016-06-10T10:45:43Z
From: Stefano Sofia
Subject: create an empty data frame and then fill in it (and then evaluate the mean of semi-hourly data for each day)

Thank you for your answer. Very clear.
(I don't like the second solution either.)
Let me then ask a final question.