Mailing List Archive: 49091 messages

[REBOL] Exercise: Calculate # work days between two dates

From: edoconnor::gmail::com at: 31-Jan-2007 16:22

```
I found Sununda's algorithm challenge to be very interesting. I'm often
amazed by the different approaches to a given problem.

In this spirit, I thought I'd offer up a basic exercise based on a
post about Ruby I came across yesterday. See:

*Calculate the number of working days between two dates*

http://www.railsonwave.com/railsonwave/2007/1/30/calculate-the-number-of-working-days-between-two-dates

Here's an approach I took, which embellishes with a refinement:

calc-workdays: func [
"Return number of workdays between two dates, excluding holidays"
date1 [date!] "Start date"
date2 [date!] "End date"
holidays [block!] "Block of dates to exclude (holidays, etc.)"
/non "Return number of non-work days (weekend + holidays) between 2
dates"
/local days day1 day2 diff param
][
days: copy []
set [day1 day2] sort reduce [date1 date2]
diff: day2 - day1
param: pick [[> 5 union][< 6 exclude]] either found? non [1][2]
loop diff [
day1: day1 + 1
if do param/1 day1/weekday param/2 [append days day1]
]
return length? do param/3 days holidays
]

Results:
>> calc-workdays now/date 3-feb-2007 [1-feb-2007]
== 1
>> print calc-workdays/non now/date 3-feb-2007 [1-feb-2007]
== 2

>> calc-workdays now/date 31-dec-2007 [25-dec-2007 1-Jan-2008]
== 237
>> print calc-workdays/non now/date 31-dec-2007 [25-dec-2007 1-Jan-2008]
== 98

Anyone care to share a different or more natural approach? One of the things
I'd like to see in REBOL's future is a guide or "phrase-book" for common
expressions found in problems big and small.

Ed
```