Databases
StackOverflow2013
Postsdbo
POGroup by - select most recent 4 events
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POGroup by - select most recent 4 events
    primarykey
    data
    text
    <p>I have the following df in pandas:</p> <pre><code>df: DATE STOCK DATA1 DATA2 DATA3 01/01/12 ABC 0.40 0.88 0.22 04/01/12 ABC 0.50 0.49 0.13 07/01/12 ABC 0.85 0.36 0.83 10/01/12 ABC 0.28 0.12 0.39 01/01/13 ABC 0.86 0.87 0.58 04/01/13 ABC 0.95 0.39 0.87 07/01/13 ABC 0.60 0.25 0.56 10/01/13 ABC 0.15 0.28 0.69 01/01/11 XYZ 0.94 0.40 0.50 04/01/11 XYZ 0.65 0.19 0.81 07/01/11 XYZ 0.89 0.59 0.69 10/01/11 XYZ 0.12 0.09 0.18 01/01/12 XYZ 0.25 0.94 0.55 04/01/12 XYZ 0.07 0.22 0.67 07/01/12 XYZ 0.46 0.08 0.54 10/01/12 XYZ 0.04 0.03 0.94 ... </code></pre> <p>I want to group by the stocks, sort by date and then for specified columns (in this case DATA1 and DATA3), I want to get the last four items summed (TTM data).</p> <p>The output would look like this:</p> <pre><code>DATE STOCK DATA1 DATA2 DATA3 DATA1_TTM DATA3_TTM 01/01/12 ABC 0.40 0.88 0.22 NaN NaN 04/01/12 ABC 0.50 0.49 0.13 NaN NaN 07/01/12 ABC 0.85 0.36 0.83 NaN NaN 10/01/12 ABC 0.28 0.12 0.39 2.03 1.56 01/01/13 ABC 0.86 0.87 0.58 2.49 1.92 04/01/13 ABC 0.95 0.39 0.87 2.94 2.66 07/01/13 ABC 0.60 0.25 0.56 2.69 2.39 10/01/13 ABC 0.15 0.28 0.69 2.55 2.70 01/01/11 XYZ 0.94 0.40 0.50 NaN NaN 04/01/11 XYZ 0.65 0.19 0.81 NaN NaN 07/01/11 XYZ 0.89 0.59 0.69 NaN NaN 10/01/11 XYZ 0.12 0.09 0.18 2.59 2.18 01/01/12 XYZ 0.25 0.94 0.55 1.90 2.23 04/01/12 XYZ 0.07 0.22 0.67 1.33 2.09 07/01/12 XYZ 0.46 0.08 0.54 0.89 1.94 10/01/12 XYZ 0.04 0.03 0.94 0.82 2.70 ... </code></pre> <p>My approach so far has been to sort by date, then group, then iterate through each group and if there are 3 older events then the current event I sum. Also, I want to check to see if the dates fall within 1 year. Can anyone offer a better way in Python? Thank you.</p> <p>Added: As a clarification for the 1 year part, let's say you take the last four dates and it goes 1/1/1993, 4/1/12, 7/1/12, 10/1/12 -- a data error. I wouldn't want to sum those four. I would want that one to say NaN.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USuser1911092
    1. USuser1911092
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload