thr3ads.net - R help - [R] Take the maximum of every 12 columns [Feb 2018]

If this information is useful, please help other people find it:
Share via:

Ista Zahn

2018-Feb-20 18:00 UTC

[R] Take the maximum of every 12 columns

On Tue, Feb 20, 2018 at 11:58 AM, Bert Gunter <bgunter.4567 at gmail.com>
wrote:
> Ista, et. al: efficiency?
> (Note: I needed to correct my previous post: do.call() is required for
> pmax() over the data frame)
>
> > x <- data.frame(matrix(runif(12e6), ncol=12))
>
> > system.time(r1 <- do.call(pmax,x))
>    user  system elapsed
>   0.049   0.000   0.049
>
> > identical(r1,r2)
> [1] FALSE
> > system.time(r2 <- apply(x,1,max))
>    user  system elapsed
>   2.162   0.045   2.207
>
> ## 150 times slower!
>
> > identical(r1,r2)
> [1] TRUE
>
> pmax() is there for a reason.
> Or is there something I am missing?
>

?Personal preference I think. I prefer the consistency of apply. If speed
is an issue matrixStats is both consistent and fast:?

?library(matrixStats)
x <- matrix(runif(12e6), ncol=12)

system.time(r1 <- do.call(pmax,as.data.frame(x)))
  ##  user  system elapsed
  ## 0.109   0.000   0.109
system.time(r2 <- apply(x,1,max))
  ##  user  system elapsed
  ## 1.292   0.024   1.321
system.time(r3 <- rowMaxs(x))
  ##  user  system elapsed
  ## 0.044   0.000   0.044
?
?pmax is a fine alternative? for max special case.

Best,
Ista


>
> Cheers,
> Bert
>
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
and
> sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip
)
>
> On Tue, Feb 20, 2018 at 8:16 AM, Miluji Sb <milujisb at gmail.com>
wrote:
>
>> This is what I was looking for. Thank you everyone!
>>
>> Sincerely,
>>
>> Milu
>>
>>
>>
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Mail
>> priva di virus. www.avast.com
>>
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
>>
<#m_4297398466082743447_m_6071581590498622123_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>
>> On Tue, Feb 20, 2018 at 5:10 PM, Ista Zahn <istazahn at
gmail.com> wrote:
>>
>>> Hi Milu,
>>>
>>> byapply(df, 12, function(x) apply(x, 1, max))
>>>
>>> You might also be interested in the matrixStats package.
>>>
>>> Best,
>>> Ista
>>>
>>> On Tue, Feb 20, 2018 at 9:55 AM, Miluji Sb <milujisb at
gmail.com> wrote:
>>> >  Dear all,
>>> >
>>> > I have monthly data in wide format, I am only providing data
(at the
>>> bottom
>>> > of the email) for the first 24 columns but I have 2880 columns
in
>>> total.
>>> >
>>> > I would like to take max of every 12 columns. I have taken the
mean of
>>> > every 12 columns with the following code:
>>> >
>>> > byapply <- function(x, by, fun, ...)
>>> > {
>>> >   # Create index list
>>> >   if (length(by) == 1)
>>> >   {
>>> >     nc <- ncol(x)
>>> >     split.index <- rep(1:ceiling(nc / by), each = by,
length.out = nc)
>>> >   } else # 'by' is a vector of groups
>>> >   {
>>> >     nc <- length(by)
>>> >     split.index <- by
>>> >   }
>>> >   index.list <- split(seq(from = 1, to = nc), split.index)
>>> >
>>> >   # Pass index list to fun using sapply() and return object
>>> >   sapply(index.list, function(i)
>>> >   {
>>> >     do.call(fun, list(x[, i], ...))
>>> >   })
>>> > }
>>> >
>>> > ## Compute annual means
>>> > y <- byapply(df, 12, rowMeans)
>>> >
>>> > How can I switch rowMeans with a command that takes the
maximum? I am
>>> a bit
>>> > baffled. Any help will be appreciated. Thank you.
>>> >
>>> > Sincerely,
>>> >
>>> > Milu
>>> >
>>> > ###
>>> > dput(droplevels(head(x, 5)))
>>> > structure(list(X0 = c(295.812103271484, 297.672424316406,
>>> 299.006805419922,
>>> > 297.631500244141, 298.372741699219), X1 = c(295.361328125,
>>> > 297.345092773438,
>>> > 298.067504882812, 297.285339355469, 298.275268554688), X2
>>> > c(294.279602050781,
>>> > 296.401550292969, 296.777984619141, 296.089111328125,
297.540374755859
>>> > ), X3 = c(292.103118896484, 294.253601074219,
293.773803710938,
>>> > 293.916229248047, 296.129943847656), X4 = c(288.525024414062,
>>> > 291.274505615234, 289.502777099609, 290.723388671875,
293.615112304688
>>> > ), X5 = c(286.018371582031, 288.748565673828,
286.463134765625,
>>> > 288.393951416016, 291.710266113281), X6 = c(285.550537109375,
>>> > 288.159149169922, 285.976501464844, 287.999816894531,
291.228271484375
>>> > ), X7 = c(289.136962890625, 290.751159667969,
290.170257568359,
>>> > 291.796203613281, 293.423248291016), X8 = c(292.410003662109,
>>> > 292.701263427734, 294.25244140625, 295.320404052734,
295.248199462891
>>> > ), X9 = c(293.821655273438, 294.139068603516,
296.630157470703,
>>> > 296.963531494141, 296.036224365234), X10 = c(294.532531738281,
>>> > 295.366607666016, 297.677551269531, 296.715911865234,
296.564178466797
>>> > ), X11 = c(295.869476318359, 297.010070800781,
299.330169677734,
>>> > 297.627593994141, 297.964935302734), X12 = c(295.986236572266,
>>> > 297.675567626953, 299.056671142578, 297.598907470703,
298.481842041016
>>> > ), X13 = c(295.947601318359, 297.934448242188,
298.745391845703,
>>> > 297.704925537109, 298.819091796875), X14 = c(294.654327392578,
>>> > 296.722717285156, 297.0986328125, 296.508239746094,
297.822021484375
>>> > ), X15 = c(292.176361083984, 294.49658203125,
293.888305664062,
>>> > 294.172149658203, 296.117095947266 <(709)%20594-7266>),
X16 >>> c(288.400726318359,
>>> > 291.029113769531, 289.361907958984, 290.566772460938,
293.554016113281
>>> > ), X17 = c(285.665222167969, 288.293029785156,
286.118957519531,
>>> > 288.105285644531, 291.429382324219), X18 = c(285.971252441406,
>>> > 288.3798828125, 286.444580078125, 288.495880126953,
291.447326660156
>>> > ), X19 = c(288.79296875, 290.357543945312, 289.657928466797,
>>> > 291.449066162109, 293.095275878906), X20 = c(291.999877929688,
>>> > 292.838348388672, 293.840362548828, 294.412322998047,
294.941253662109
>>> > ), X21 = c(293.615447998047, 294.028106689453,
296.072296142578,
>>> > 296.447387695312, 295.824615478516), X22 = c(294.719848632812,
>>> > 295.392028808594, 297.453216552734, 297.114288330078,
296.883209228516
>>> > ), X23 = c(295.634429931641, 296.783294677734,
298.592346191406,
>>> > 297.469512939453, 297.832122802734)), .Names =
c("X0", "X1",
>>> > "X2", "X3", "X4",
"X5", "X6", "X7", "X8", "X9",
"X10", "X11",
>>> > "X12", "X13", "X14",
"X15", "X16", "X17", "X18",
"X19", "X20",
>>> > "X21", "X22", "X23"), row.names
= c(NA, 5L), class = "data.frame")
>>> >
>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
>>> =link&utm_campaign=sig-email&utm_content=webmail>
>>> > Mail
>>> > priva di virus. www.avast.com
>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
>>> =link&utm_campaign=sig-email&utm_content=webmail>
>>> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>> >
>>> >         [[alternative HTML version deleted]]
>>> >
>>> > ______________________________________________
>>> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and
more, see
>>> > https://stat.ethz.ch/mailman/listinfo/r-help
>>> > PLEASE do read the posting guide
http://www.R-project.org/posti
>>> ng-guide.html
>>> > and provide commented, minimal, self-contained, reproducible
code.
>>>
>>
>>
>
	[[alternative HTML version deleted]]

Henrik Bengtsson

2018-Feb-20 21:12 UTC

head link

[R] Take the maximum of every 12 columns

It looks like OP uses a data.frame, so in order to use matrixStats
(I'm the author) one would have to pay the price to coerce to a matrix
before using matrixStats::rowMaxs().  However, if it is that the
original data could equally well live in a matrix, then matrixStats
should be computational efficient for this task.  (I've seen cases
where an original matrix was turned into a data.frame just because
that is what is commonly used elsewhere and because the user may not
pay attention to the differences between matrices and data.frame.)

If the original data would be a matrix 'X', then one can do the
following with matrixStats:

Y <- sapply(seq(from = 0, to = 2880, by = 12), FUN = function(offset) {
   rowMaxs(X, cols = offset + 1:12)
})

which avoids internal temporary copies required when using regular
subsetting, e.g.

Y <- sapply(seq(from = 0, to = 2880, by = 12), FUN = function(offset) {
   rowMaxs(X[, offset + 1:12])
})

Subsetting data frames by columns is already efficient, so the same
argument does not apply there.

/Henrik

On Tue, Feb 20, 2018 at 10:00 AM, Ista Zahn <istazahn at gmail.com>
wrote:> On Tue, Feb 20, 2018 at 11:58 AM, Bert Gunter <bgunter.4567 at
gmail.com>
> wrote:
>
>> Ista, et. al: efficiency?
>> (Note: I needed to correct my previous post: do.call() is required for
>> pmax() over the data frame)
>>
>> > x <- data.frame(matrix(runif(12e6), ncol=12))
>>
>> > system.time(r1 <- do.call(pmax,x))
>>    user  system elapsed
>>   0.049   0.000   0.049
>>
>> > identical(r1,r2)
>> [1] FALSE
>> > system.time(r2 <- apply(x,1,max))
>>    user  system elapsed
>>   2.162   0.045   2.207
>>
>> ## 150 times slower!
>>
>> > identical(r1,r2)
>> [1] TRUE
>>
>> pmax() is there for a reason.
>> Or is there something I am missing?
>>
>
>
> Personal preference I think. I prefer the consistency of apply. If speed
> is an issue matrixStats is both consistent and fast:
>
> library(matrixStats)
> x <- matrix(runif(12e6), ncol=12)
>
> system.time(r1 <- do.call(pmax,as.data.frame(x)))
>   ##  user  system elapsed
>   ## 0.109   0.000   0.109
> system.time(r2 <- apply(x,1,max))
>   ##  user  system elapsed
>   ## 1.292   0.024   1.321
> system.time(r3 <- rowMaxs(x))
>   ##  user  system elapsed
>   ## 0.044   0.000   0.044
>
> pmax is a fine alternative for max special case.
>
> Best,
> Ista
>
>
>
>>
>> Cheers,
>> Bert
>>
>>
>>
>> Bert Gunter
>>
>> "The trouble with having an open mind is that people keep coming
along and
>> sticking things into it."
>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic
strip )
>>
>> On Tue, Feb 20, 2018 at 8:16 AM, Miluji Sb <milujisb at
gmail.com> wrote:
>>
>>> This is what I was looking for. Thank you everyone!
>>>
>>> Sincerely,
>>>
>>> Milu
>>>
>>>
>>>
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Mail
>>> priva di virus. www.avast.com
>>>
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
>>>
<#m_4297398466082743447_m_6071581590498622123_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>
>>> On Tue, Feb 20, 2018 at 5:10 PM, Ista Zahn <istazahn at
gmail.com> wrote:
>>>
>>>> Hi Milu,
>>>>
>>>> byapply(df, 12, function(x) apply(x, 1, max))
>>>>
>>>> You might also be interested in the matrixStats package.
>>>>
>>>> Best,
>>>> Ista
>>>>
>>>> On Tue, Feb 20, 2018 at 9:55 AM, Miluji Sb <milujisb at
gmail.com> wrote:
>>>> >  Dear all,
>>>> >
>>>> > I have monthly data in wide format, I am only providing
data (at the
>>>> bottom
>>>> > of the email) for the first 24 columns but I have 2880
columns in
>>>> total.
>>>> >
>>>> > I would like to take max of every 12 columns. I have taken
the mean of
>>>> > every 12 columns with the following code:
>>>> >
>>>> > byapply <- function(x, by, fun, ...)
>>>> > {
>>>> >   # Create index list
>>>> >   if (length(by) == 1)
>>>> >   {
>>>> >     nc <- ncol(x)
>>>> >     split.index <- rep(1:ceiling(nc / by), each = by,
length.out = nc)
>>>> >   } else # 'by' is a vector of groups
>>>> >   {
>>>> >     nc <- length(by)
>>>> >     split.index <- by
>>>> >   }
>>>> >   index.list <- split(seq(from = 1, to = nc),
split.index)
>>>> >
>>>> >   # Pass index list to fun using sapply() and return
object
>>>> >   sapply(index.list, function(i)
>>>> >   {
>>>> >     do.call(fun, list(x[, i], ...))
>>>> >   })
>>>> > }
>>>> >
>>>> > ## Compute annual means
>>>> > y <- byapply(df, 12, rowMeans)
>>>> >
>>>> > How can I switch rowMeans with a command that takes the
maximum? I am
>>>> a bit
>>>> > baffled. Any help will be appreciated. Thank you.
>>>> >
>>>> > Sincerely,
>>>> >
>>>> > Milu
>>>> >
>>>> > ###
>>>> > dput(droplevels(head(x, 5)))
>>>> > structure(list(X0 = c(295.812103271484, 297.672424316406,
>>>> 299.006805419922,
>>>> > 297.631500244141, 298.372741699219), X1 = c(295.361328125,
>>>> > 297.345092773438,
>>>> > 298.067504882812, 297.285339355469, 298.275268554688), X2
>>>> > c(294.279602050781,
>>>> > 296.401550292969, 296.777984619141, 296.089111328125,
297.540374755859
>>>> > ), X3 = c(292.103118896484, 294.253601074219,
293.773803710938,
>>>> > 293.916229248047, 296.129943847656), X4 =
c(288.525024414062,
>>>> > 291.274505615234, 289.502777099609, 290.723388671875,
293.615112304688
>>>> > ), X5 = c(286.018371582031, 288.748565673828,
286.463134765625,
>>>> > 288.393951416016, 291.710266113281), X6 =
c(285.550537109375,
>>>> > 288.159149169922, 285.976501464844, 287.999816894531,
291.228271484375
>>>> > ), X7 = c(289.136962890625, 290.751159667969,
290.170257568359,
>>>> > 291.796203613281, 293.423248291016), X8 =
c(292.410003662109,
>>>> > 292.701263427734, 294.25244140625, 295.320404052734,
295.248199462891
>>>> > ), X9 = c(293.821655273438, 294.139068603516,
296.630157470703,
>>>> > 296.963531494141, 296.036224365234), X10 =
c(294.532531738281,
>>>> > 295.366607666016, 297.677551269531, 296.715911865234,
296.564178466797
>>>> > ), X11 = c(295.869476318359, 297.010070800781,
299.330169677734,
>>>> > 297.627593994141, 297.964935302734), X12 =
c(295.986236572266,
>>>> > 297.675567626953, 299.056671142578, 297.598907470703,
298.481842041016
>>>> > ), X13 = c(295.947601318359, 297.934448242188,
298.745391845703,
>>>> > 297.704925537109, 298.819091796875), X14 =
c(294.654327392578,
>>>> > 296.722717285156, 297.0986328125, 296.508239746094,
297.822021484375
>>>> > ), X15 = c(292.176361083984, 294.49658203125,
293.888305664062,
>>>> > 294.172149658203, 296.117095947266
<(709)%20594-7266>), X16 >>>> c(288.400726318359,
>>>> > 291.029113769531, 289.361907958984, 290.566772460938,
293.554016113281
>>>> > ), X17 = c(285.665222167969, 288.293029785156,
286.118957519531,
>>>> > 288.105285644531, 291.429382324219), X18 =
c(285.971252441406,
>>>> > 288.3798828125, 286.444580078125, 288.495880126953,
291.447326660156
>>>> > ), X19 = c(288.79296875, 290.357543945312,
289.657928466797,
>>>> > 291.449066162109, 293.095275878906), X20 =
c(291.999877929688,
>>>> > 292.838348388672, 293.840362548828, 294.412322998047,
294.941253662109
>>>> > ), X21 = c(293.615447998047, 294.028106689453,
296.072296142578,
>>>> > 296.447387695312, 295.824615478516), X22 =
c(294.719848632812,
>>>> > 295.392028808594, 297.453216552734, 297.114288330078,
296.883209228516
>>>> > ), X23 = c(295.634429931641, 296.783294677734,
298.592346191406,
>>>> > 297.469512939453, 297.832122802734)), .Names =
c("X0", "X1",
>>>> > "X2", "X3", "X4",
"X5", "X6", "X7", "X8", "X9",
"X10", "X11",
>>>> > "X12", "X13", "X14",
"X15", "X16", "X17", "X18",
"X19", "X20",
>>>> > "X21", "X22", "X23"),
row.names = c(NA, 5L), class = "data.frame")
>>>> >
>>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
>>>> =link&utm_campaign=sig-email&utm_content=webmail>
>>>> > Mail
>>>> > priva di virus. www.avast.com
>>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
>>>> =link&utm_campaign=sig-email&utm_content=webmail>
>>>> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>> >
>>>> >         [[alternative HTML version deleted]]
>>>> >
>>>> > ______________________________________________
>>>> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and
more, see
>>>> > https://stat.ethz.ch/mailman/listinfo/r-help
>>>> > PLEASE do read the posting guide
http://www.R-project.org/posti
>>>> ng-guide.html
>>>> > and provide commented, minimal, self-contained,
reproducible code.
>>>>
>>>
>>>
>>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Miluji Sb

2018-Feb-21 11:00 UTC

head link

[R] Take the maximum of every 12 columns

Dear Henrik,

This is great - thank you so much!

Sincerely,

Milu

On Tue, Feb 20, 2018 at 10:12 PM, Henrik Bengtsson <
henrik.bengtsson at gmail.com> wrote:
> It looks like OP uses a data.frame, so in order to use matrixStats
> (I'm the author) one would have to pay the price to coerce to a matrix
> before using matrixStats::rowMaxs().  However, if it is that the
> original data could equally well live in a matrix, then matrixStats
> should be computational efficient for this task.  (I've seen cases
> where an original matrix was turned into a data.frame just because
> that is what is commonly used elsewhere and because the user may not
> pay attention to the differences between matrices and data.frame.)
>
> If the original data would be a matrix 'X', then one can do the
> following with matrixStats:
>
> Y <- sapply(seq(from = 0, to = 2880, by = 12), FUN = function(offset) {
>    rowMaxs(X, cols = offset + 1:12)
> })
>
> which avoids internal temporary copies required when using regular
> subsetting, e.g.
>
> Y <- sapply(seq(from = 0, to = 2880, by = 12), FUN = function(offset) {
>    rowMaxs(X[, offset + 1:12])
> })
>
> Subsetting data frames by columns is already efficient, so the same
> argument does not apply there.
>
> /Henrik
>
> On Tue, Feb 20, 2018 at 10:00 AM, Ista Zahn <istazahn at gmail.com>
wrote:
> > On Tue, Feb 20, 2018 at 11:58 AM, Bert Gunter <bgunter.4567 at
gmail.com>
> > wrote:
> >
> >> Ista, et. al: efficiency?
> >> (Note: I needed to correct my previous post: do.call() is required
for
> >> pmax() over the data frame)
> >>
> >> > x <- data.frame(matrix(runif(12e6), ncol=12))
> >>
> >> > system.time(r1 <- do.call(pmax,x))
> >>    user  system elapsed
> >>   0.049   0.000   0.049
> >>
> >> > identical(r1,r2)
> >> [1] FALSE
> >> > system.time(r2 <- apply(x,1,max))
> >>    user  system elapsed
> >>   2.162   0.045   2.207
> >>
> >> ## 150 times slower!
> >>
> >> > identical(r1,r2)
> >> [1] TRUE
> >>
> >> pmax() is there for a reason.
> >> Or is there something I am missing?
> >>
> >
> >
> > Personal preference I think. I prefer the consistency of apply. If
speed
> > is an issue matrixStats is both consistent and fast:
> >
> > library(matrixStats)
> > x <- matrix(runif(12e6), ncol=12)
> >
> > system.time(r1 <- do.call(pmax,as.data.frame(x)))
> >   ##  user  system elapsed
> >   ## 0.109   0.000   0.109
> > system.time(r2 <- apply(x,1,max))
> >   ##  user  system elapsed
> >   ## 1.292   0.024   1.321
> > system.time(r3 <- rowMaxs(x))
> >   ##  user  system elapsed
> >   ## 0.044   0.000   0.044
> >
> > pmax is a fine alternative for max special case.
> >
> > Best,
> > Ista
> >
> >
> >
> >>
> >> Cheers,
> >> Bert
> >>
> >>
> >>
> >> Bert Gunter
> >>
> >> "The trouble with having an open mind is that people keep
coming along
> and
> >> sticking things into it."
> >> -- Opus (aka Berkeley Breathed in his "Bloom County"
comic strip )
> >>
> >> On Tue, Feb 20, 2018 at 8:16 AM, Miluji Sb <milujisb at
gmail.com> wrote:
> >>
> >>> This is what I was looking for. Thank you everyone!
> >>>
> >>> Sincerely,
> >>>
> >>> Milu
> >>>
> >>>
> >>> <https://www.avast.com/sig-email?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail> Mail
> >>> priva di virus. www.avast.com
> >>> <https://www.avast.com/sig-email?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail>
> >>> <#m_4297398466082743447_m_6071581590498622123_DAB4FAD8-
> 2DD7-40BB-A1B8-4E2AA1F9FDF2>
> >>>
> >>> On Tue, Feb 20, 2018 at 5:10 PM, Ista Zahn <istazahn at
gmail.com> wrote:
> >>>
> >>>> Hi Milu,
> >>>>
> >>>> byapply(df, 12, function(x) apply(x, 1, max))
> >>>>
> >>>> You might also be interested in the matrixStats package.
> >>>>
> >>>> Best,
> >>>> Ista
> >>>>
> >>>> On Tue, Feb 20, 2018 at 9:55 AM, Miluji Sb <milujisb at
gmail.com>
> wrote:
> >>>> >  Dear all,
> >>>> >
> >>>> > I have monthly data in wide format, I am only
providing data (at the
> >>>> bottom
> >>>> > of the email) for the first 24 columns but I have
2880 columns in
> >>>> total.
> >>>> >
> >>>> > I would like to take max of every 12 columns. I have
taken the mean
> of
> >>>> > every 12 columns with the following code:
> >>>> >
> >>>> > byapply <- function(x, by, fun, ...)
> >>>> > {
> >>>> >   # Create index list
> >>>> >   if (length(by) == 1)
> >>>> >   {
> >>>> >     nc <- ncol(x)
> >>>> >     split.index <- rep(1:ceiling(nc / by), each =
by, length.out > nc)
> >>>> >   } else # 'by' is a vector of groups
> >>>> >   {
> >>>> >     nc <- length(by)
> >>>> >     split.index <- by
> >>>> >   }
> >>>> >   index.list <- split(seq(from = 1, to = nc),
split.index)
> >>>> >
> >>>> >   # Pass index list to fun using sapply() and return
object
> >>>> >   sapply(index.list, function(i)
> >>>> >   {
> >>>> >     do.call(fun, list(x[, i], ...))
> >>>> >   })
> >>>> > }
> >>>> >
> >>>> > ## Compute annual means
> >>>> > y <- byapply(df, 12, rowMeans)
> >>>> >
> >>>> > How can I switch rowMeans with a command that takes
the maximum? I
> am
> >>>> a bit
> >>>> > baffled. Any help will be appreciated. Thank you.
> >>>> >
> >>>> > Sincerely,
> >>>> >
> >>>> > Milu
> >>>> >
> >>>> > ###
> >>>> > dput(droplevels(head(x, 5)))
> >>>> > structure(list(X0 = c(295.812103271484,
297.672424316406,
> >>>> 299.006805419922,
> >>>> > 297.631500244141, 298.372741699219), X1 =
c(295.361328125,
> >>>> > 297.345092773438,
> >>>> > 298.067504882812, 297.285339355469,
298.275268554688), X2 > >>>> > c(294.279602050781,
> >>>> > 296.401550292969, 296.777984619141, 296.089111328125,
> 297.540374755859
> >>>> > ), X3 = c(292.103118896484, 294.253601074219,
293.773803710938,
> >>>> > 293.916229248047, 296.129943847656), X4 =
c(288.525024414062,
> >>>> > 291.274505615234, 289.502777099609, 290.723388671875,
> 293.615112304688
> >>>> > ), X5 = c(286.018371582031, 288.748565673828,
286.463134765625,
> >>>> > 288.393951416016, 291.710266113281), X6 =
c(285.550537109375,
> >>>> > 288.159149169922, 285.976501464844, 287.999816894531,
> 291.228271484375
> >>>> > ), X7 = c(289.136962890625, 290.751159667969,
290.170257568359,
> >>>> > 291.796203613281, 293.423248291016), X8 =
c(292.410003662109,
> >>>> > 292.701263427734, 294.25244140625, 295.320404052734,
> 295.248199462891
> >>>> > ), X9 = c(293.821655273438, 294.139068603516,
296.630157470703,
> >>>> > 296.963531494141, 296.036224365234), X10 =
c(294.532531738281,
> >>>> > 295.366607666016, 297.677551269531, 296.715911865234,
> 296.564178466797
> >>>> > ), X11 = c(295.869476318359, 297.010070800781,
299.330169677734,
> >>>> > 297.627593994141, 297.964935302734), X12 =
c(295.986236572266,
> >>>> > 297.675567626953, 299.056671142578, 297.598907470703,
> 298.481842041016
> >>>> > ), X13 = c(295.947601318359, 297.934448242188,
298.745391845703,
> >>>> > 297.704925537109, 298.819091796875), X14 =
c(294.654327392578,
> >>>> > 296.722717285156, 297.0986328125, 296.508239746094,
297.822021484375
> >>>> > ), X15 = c(292.176361083984, 294.49658203125,
293.888305664062,
> >>>> > 294.172149658203, 296.117095947266
<(709)%20594-7266>), X16 > >>>> c(288.400726318359,
> >>>> > 291.029113769531, 289.361907958984, 290.566772460938,
> 293.554016113281
> >>>> > ), X17 = c(285.665222167969, 288.293029785156,
286.118957519531,
> >>>> > 288.105285644531, 291.429382324219), X18 =
c(285.971252441406,
> >>>> > 288.3798828125, 286.444580078125, 288.495880126953,
291.447326660156
> >>>> > ), X19 = c(288.79296875, 290.357543945312,
289.657928466797,
> >>>> > 291.449066162109, 293.095275878906), X20 =
c(291.999877929688,
> >>>> > 292.838348388672, 293.840362548828, 294.412322998047,
> 294.941253662109
> >>>> > ), X21 = c(293.615447998047, 294.028106689453,
296.072296142578,
> >>>> > 296.447387695312, 295.824615478516), X22 =
c(294.719848632812,
> >>>> > 295.392028808594, 297.453216552734, 297.114288330078,
> 296.883209228516
> >>>> > ), X23 = c(295.634429931641, 296.783294677734,
298.592346191406,
> >>>> > 297.469512939453, 297.832122802734)), .Names =
c("X0", "X1",
> >>>> > "X2", "X3", "X4",
"X5", "X6", "X7", "X8", "X9",
"X10", "X11",
> >>>> > "X12", "X13", "X14",
"X15", "X16", "X17", "X18",
"X19", "X20",
> >>>> > "X21", "X22", "X23"),
row.names = c(NA, 5L), class = "data.frame")
> >>>> >
> >>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
> >>>>
=link&utm_campaign=sig-email&utm_content=webmail>
> >>>> > Mail
> >>>> > priva di virus. www.avast.com
> >>>> >
<https://www.avast.com/sig-email?utm_medium=email&utm_source
> >>>>
=link&utm_campaign=sig-email&utm_content=webmail>
> >>>> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> >>>> >
> >>>> >         [[alternative HTML version deleted]]
> >>>> >
> >>>> > ______________________________________________
> >>>> > R-help at r-project.org mailing list -- To
UNSUBSCRIBE and more, see
> >>>> > https://stat.ethz.ch/mailman/listinfo/r-help
> >>>> > PLEASE do read the posting guide
http://www.R-project.org/posti
> >>>> ng-guide.html
> >>>> > and provide commented, minimal, self-contained,
reproducible code.
> >>>>
> >>>
> >>>
> >>
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/
> posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/
> posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Apparently Analagous Threads

Search for more possibly parallel threads

R help - Feb 2018 - Take the maximum of every 12 columns

[R] Take the maximum of every 12 columns

[R] Take the maximum of every 12 columns

[R] Take the maximum of every 12 columns

Apparently Analagous Threads