Calculate difference on two dates

[quarkpott]

Hello,

Maybe someone can help me.
I have a Read Start column and a Read End column. How can I create a read duration column that shows the days between the two dates? How can I create a read duration column that shows the days between the two dates?
I need a column that depends on other columns, but then unfortunately I do not get more.

I would be very glad about help.

[chaley]

Originally Posted by quarkpott

Hello,

Maybe someone can help me.
I have a Read Start column and a Read End column. How can I create a read duration column that shows the days between the two dates? How can I create a read duration column that shows the days between the two dates?
I need a column that depends on other columns, but then unfortunately I do not get more.

I would be very glad about help.

See The calibre template language, General Program Mode, and in particular the days_between() function.

You probably want a template like this, with the lookup names changed appropriately.

program:
    days_between($$#read_end, $$#read_start)

The days_between() function returns fractional days. If you want an integer then use either

program:
    floor(days_between($$#read_end, $$#read_start))

program:
    round(days_between($$#read_end, $$#read_start))

[quarkpott]

Thanks, I'll look into it and get back to you if I can't get it to work.

[quarkpott]

I think I don't understand something.
I have copied in the templates and changed for me and have specified the template in the column. Shouldn't it actually work then?
Please excuse my stupidity

[ownedbycats]

program: Lesedaeur()

[quarkpott]

Originally Posted by ownedbycats

program: Lesedaeur()

Then 0 is displayed in the column, although it should actually be 2

[quarkpott]

With some experimenting it worked now, thank you.

[ownedbycats]

If it helps for the future, I've found most of my days_between() errors happened because I put the two dates in the wrong order.

[quarkpott]

Me again.
Is it perhaps also possible that the field is only populated when Read Begin and Read End are filled in?
At the moment there is always a 0 entered.
Thanks in advance for the effort.

[ownedbycats]

Originally Posted by quarkpott

Me again.
Is it perhaps also possible that the field is only populated when Read Begin and Read End are filled in?
At the moment there is always a 0 entered.
Thanks in advance for the effort.

Is odd as I just got a blank, but hopefully this will work:

program:

	if 
		$$#date1 && $$#date2
	then
		days_between($$#date1, $$#date2)
	fi

[dunhill]

I have it configured like this
Taking the start and read ended column

program: format_number(days_between(raw_field('#finished'), raw_field('#started')),"{0:5.0f}")

[quarkpott]

Thank you. Worked.
Slowly it becomes as desired.

I also have books that I have read but have not set a date.
Is it perhaps also possible to write an unknown for these in Read Start, Read End and read duration?

[quarkpott]

That would be the last one, sorry for all the questions.

[quarkpott]

Got it myself, thanks anyway for all the help here

[dunhill]

They appear to me like this, like the image
The columns I have are:
Status (Read, To Read, Reading)
Title
Author
Date (From Calibre)
Ranking
Tags
Serie
Editorial
Published
Pages
Started (Read start date)
Finished (Date the reading finished)
Days (Number of days to read it)