Custom Column - How Long to Read

[Mansoul]

I've got Calibre showing page and word counts, I'd like to have a custom column that reads the word count, divides by reading speed, then divides by 60 to produce a value in hours and minutes.

I've looked through the template language doc but I'm lost, can anyone please help me out?

[JSWolf]

Originally Posted by Mansoul

I've got Calibre showing page and word counts, I'd like to have a custom column that reads the word count, divides by reading speed, then divides by 60 to produce a value in hours and minutes.

I've looked through the template language doc but I'm lost, can anyone please help me out?

Try reading a few books and time yourself while reading them you can figure out the math from there.

[davidfor]

Something like the following is what you want:

program:
format_number(divide(divide(raw_field('#words'),1000),60), '{0:5,.2f}')

In that, the 1000 is the reading speed. You can do it with one divide if you calculate the reading speed in words per hour rather than words per minute.

The formatting will give the number with two decimal points.

[Mansoul]

Thank you both, again.

I couldn't figure out where the code goes, tried custom columns and template functions but the code itself appears in the column.

No bother, I can use word the count to give me an idea.

[davidfor]

It is the template for a custom column of type "Column built from other columns". Put all of the code that I posted into that. This include the "program:".

[JSWolf]

If you use the Kobo time count, you can figure out your reading speed and use that to get a more accurate result. I suggest at least 5 times.

[Loosheesh]

Originally Posted by davidfor

It is the template for a custom column of type "Column built from other columns". Put all of the code that I posted into that. This include the "program:".

I'm also interested in creating a custom column like this and I'd like to know what to put in the other fields (function and argument):

[davidfor]

Originally Posted by Loosheesh

I'm also interested in creating a custom column like this and I'd like to know what to put in the other fields (function and argument):

That is the wrong place. From there, you can create a function to be used elsewhere. If you are trying to do what @Mansoul has asked, this would be overkill.

The instructions for adding custom column with a template are in Techniques to use plugboards, custom columns and templates.

[kcar181]

Originally Posted by davidfor

Something like the following is what you want:

program:
format_number(divide(divide(raw_field('#words'),1000),60), '{0:5,.2f}')

In that, the 1000 is the reading speed. You can do it with one divide if you calculate the reading speed in words per hour rather than words per minute.

The formatting will give the number with two decimal points.

This is really cool thanks for this. I'm getting numbers like 2.29 would that be 2 hours 29 min?

EDIT: Now I see numbers like 1.86 so im guessing not hours/minutes. Anyway to convert?

[ownedbycats]

Originally Posted by kcar181

This is really cool thanks for this. I'm getting numbers like 2.29 would that be 2 hours 29 min?

EDIT: Now I see numbers like 1.86 so im guessing not hours/minutes. Anyway to convert?

Multiply by 60 to get the number of minutes.

For 2.29 hours that's ~137 minutes.

Divide that by sixty again using whole numbers and the remainder is 17 minutes.

You end up with 2:17.

[kcar181]

Ok so if id like just minutes im guessing this would do the trick

program:
format_number(multiply(divide(divide(raw_field('#chars'),310),60),60), '{0:5,.2f}')

And the first code was closer to hours so 1.86 would translate to 2 hours 26 minutes?

EDIT: Ok learning something new. So I think 1.86 would be a decimal hour so 1 hour and 86/100 of an hour.

[Loosheesh]

Originally Posted by davidfor

That is the wrong place. From there, you can create a function to be used elsewhere. If you are trying to do what @Mansoul has asked, this would be overkill.

The instructions for adding custom column with a template are in Techniques to use plugboards, custom columns and templates.

I initially put the code in the right place but left out "program:" (though you specifically said to add it! ). When it didn't work at first, I got to thinking I should've gone to the Template functions section instead

Anyway, it works now

[chaley]

Originally Posted by ownedbycats

Multiply by 60 to get the number of minutes.

For 2.29 hours that's ~137 minutes.

Divide that by sixty again using whole numbers and the remainder is 17 minutes.

You end up with 2:17.

Unfortunately you currently can't do that calculation in the template language. All the arithmetic is floating point.

I am going to add some more math functions: floor(x), ceiling(x), fractional_part(x), round(x), and mod(x, y). Using these (when they are released), you will be able to compute hours:minutes from fractional hours using something like this template.

program:
# total_hours should be a field reference
	fractional_hours = 3.6982;
# Compute the number of hours in total minutes as an integer
	display_hours = floor(fractional_hours );
# Compute the number of minutes left over after display_hours
	display_mins = round(multiply(fractional_part(fractional_hours ), 60));
# Format the results as h:mm
	strcat(display_hours, ':', format_number(display_mins, '02d'))

This template produces the result "3:42"

[davidfor]

And here was me thinking of doing:

program:
minutes = divide(raw_field('#words'),310);
hours = divide(minutes, 60);
hours = list_item(hours,0,'.');
minutes = subtract(minutes, multiply(hours,60));
minutes = format_number(minutes, '02,.0f');
strcat(hours,':',minutes)

Ugly, but it seems to work. I'd probably combine a couple of lines, but, separating them helps the debugging.

But, I've wanted some of your new functions before. So, I'm happy to see them.

[Mansoul]

I missed out the 'program:' in mine as well, got it working now.

Really appreciate everyone's input!