title: How to use Group_By() on multiple columns to sum the rest of the columns
body: <p>This is similar to <a href="https://stackoverflow.com/questions/2421388/using-group-by-on-multiple-columns">Using group by on multiple columns</a> but I'm not too sure how to apply it to my case.</p>
  <p>Here is the head of my data
  I would like to <code>group_by(Date, Participant Code)</code>, and then sum all the other columns.</p>
  <pre><code>head(all_ergo)
  # A tibble: 6 × 10
    Date       time_bike distance bike_calories   power `Participant Code` time_active time_total desk_ca…¹ total…²
    &lt;date&gt;         &lt;dbl&gt;    &lt;dbl&gt;         &lt;dbl&gt;   &lt;dbl&gt; &lt;chr&gt;                    &lt;dbl&gt;      &lt;dbl&gt;     &lt;dbl&gt;   &lt;dbl&gt;
  1 2022-04-12       120        0             0 0.00613 AE1_01                     360        360      11.0    11.0
  2 2022-04-12       120        0             0 0.00613 AE1_01                    1920       1920      58.6    58.6
  3 2022-04-12       120        0             0 0.00613 AE1_01                    3480       3480     106.    106. 
  4 2022-04-12       120        0             0 0.00613 AE1_01                    3540       3540     108.    108. 
  5 2022-04-12       120        0             0 0.00580 AE1_01                     360        360      11.0    11.0
  6 2022-04-12       120        0             0 0.00580 AE1_01                    1920       1920      58.6    58.6
  # … with abbreviated variable names ¹​desk_calories, ²​total_calories
  </code></pre>
  <p>Here I used a similar code, but I can't figure out how to expand it to grouping by 2 columns</p>
  <pre><code>Summary_PRE &lt;- workday_PRE%&gt;% group_by(Date) %&gt;% mutate_if(is.character,as.numeric) %&gt;% summarise(across(Axis1:Counter,sum))
  Summary_PRE &lt;- subset (Summary_PRE, select = -c(Axis1,Axis2,Axis3,VM))
  </code></pre>