[R] Summing using a boolean index vector (repost in plain text).
Dan Stanger
DStanger at EatonVance.Com
Fri Jun 18 19:12:20 CEST 2010
Hello Jim,
Thank you for getting back to me. Cumsum does exactly what I needed as the following example shows.
[1] TRUE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE TRUE FALSE
> cumsum(x)
[1] 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 6 6 6 6 6 7 7 7 7
Dan Stanger
Eaton Vance Management
200 State Street
Boston, MA 02109
617 598 8261
-----Original Message-----
From: jim holtman [mailto:jholtman at gmail.com]
Sent: Friday, June 18, 2010 12:24 PM
To: Dan Stanger
Cc: R-help at r-project.org
Subject: Re: [R] Summing using a boolean index vector (repost in plain text).
?cumsum
?ave
But without data (follow the posting guide) specific solution can not
be specified
On Fri, Jun 18, 2010 at 11:39 AM, Dan Stanger <DStanger at eatonvance.com> wrote:
> Hello all:
> I have a dataframe f of weekdays and value, and a Boolean vector with Fridays set to true, and other days set to false, created by fridays<-(diff(f$weekdays) < -1).
> I would like to create a vector of sums, for each week. That is, start summing on the first false value in the vector, and when I get to true, produce the sum, and start summing again.
> Is there a vector operation which can do this, without writing an explicit loop?
> Thank you,
> Dan Stanger
> P.S. Sorry about the repost.
> Eaton Vance Management
> 200 State Street
> Boston, MA 02109
> 617 598 8261
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
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