Hi All,

I've been struggling on that one for a couple of days. I've tried several
things, but nothing is worth publishing.

I'm working with a bird nests data frame for which I have a laying date (LD)
and a fledgling date (FD) (in calendar Julian date) by nest id. For the
period spanning between LD and SD, the nest is termed "active". Each nest id
occur once in the data frame.

How could I get the cumulative percentage of active nests by date within a
specified time frame ? Let's say from Julian date 60 to 273 ?

I would like the results to look like this :

Julian_date  prct_ active
60                      0
61                      5
62                      10
63                      25
...

Here is an example of the data frame

nest_id     LD     FD
   1    193    219
   2    131    159
   3    196    221
   4    152    179
   5    136    164
…

Cheers,

Sebastien

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