[R] Count number of Fridays in a month

[Abhinaba Roy]

Hi Duncan,

I have converted the string to a POSIXIt object using

> strptime('31-may-2014',format="%d-%b-%Y")

But could not figure out the way forward.

Could you please elaborate a bit?

On Fri, Oct 10, 2014 at 5:14 PM, Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:

> On 10/10/2014, 7:28 AM, Abhinaba Roy wrote:
> > Hi R helpers,
> >
> > I want to write a function which will
> >
> > 1. Count the number of fridays in the current month ( to extract month
> from
> > given date) and also the number of fridays in the preceeding month
> >
> > 2. Calculate the ratio of the number of fridays in current month to the
> > number of fridays in the precceding month
> >
> > 3. Return a integer value calculated as
> >     ifelse(ratio>1,1,ifesle(ration<1,-1),0)
> >
> > The date which is passed is in the format *'31-may-2014'*
> >
> > So, given the date '31-may-2014'
> >
> > Number of fridays in May2014 = 5
> > Number of fridays in Apr2014 = 4
> >
> > Ratio = 5/4 >1
> > Hence, the function will return a value 1
> >
> > I want to call the function by passing '31-may-2014' as an argument
> >
> > How can this be done in R?
> >
> > Any help will be appreciated
>
> Convert your string to a POSIXlt object using as.POSIXlt.  Then you can
> extract year, month and weekday from the result, and go from there.
> (The only unobvious part is figuring out how many days are in each
> month, but there are questions online giving various ways to do this.)
>
> Duncan Murdoch
>
>

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