[R] Is there an variant of apply() that does not return anything?
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
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Re: [R] Is there an variant of apply() that does not return anything?
On Nov 20, 2009, at 10:21 AM, Peng Yu wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
Just use a for() loop. If you are plotting things, the performance
bottleneck is not going to be in the loop.
Sometimes, we get too anal about avoiding for() loops.
HTH,
Marc Schwartz
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Re: [R] Is there an variant of apply() that does not return anything?
On Thu, Nov 19, 2009 at 2:21 PM, Peng Yu pengyu...@gmail.com wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
Take a look at the l_ply(), a_ply() and d_ply() functions from
Hadley's plyr package. They are a refinement and extension to the
apply family of functions and the underscore, _, in the function
names indicates that they have no return value.
-Charlie
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Re: [R] Is there an variant of apply() that does not return anything?
invisible(apply(...))
On Thu, Nov 19, 2009 at 5:21 PM, Peng Yu pengyu...@gmail.com wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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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Re: [R] Is there an variant of apply() that does not return anything?
On Thu, Nov 19, 2009 at 4:27 PM, Marc Schwartz marc_schwa...@me.com wrote:
On Nov 20, 2009, at 10:21 AM, Peng Yu wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
Just use a for() loop. If you are plotting things, the performance
bottleneck is not going to be in the loop.
Sometimes, we get too anal about avoiding for() loops.
Is there a way to get the name of the list in the loop body?
List=list(a='c',b='x',e='q')
for(x in List) { print(x) }
[1] c
[1] x
[1] q
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Re: [R] Is there an variant of apply() that does not return anything?
I want to use both the name and the content. Although, I could do the
following thing.
for(x in names(List)) {
do some thing with x
do some thing with List[[x]]
}
However, I'd prefer something like the following if R offers such
functionality. But it seems not.
for(x in List) {
do something with the name of x
do something with x
}
On Fri, Nov 20, 2009 at 4:35 PM, Jorge Ivan Velez
jorgeivanve...@gmail.com wrote:
If I understood correctly
for(x in names(List)) print(x)
should do what you asked.
HTH, Jorge
On Thu, Nov 19, 2009 at 5:31 PM, Peng Yu wrote:
On Thu, Nov 19, 2009 at 4:27 PM, Marc Schwartz marc_schwa...@me.com
wrote:
On Nov 20, 2009, at 10:21 AM, Peng Yu wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in 'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
Just use a for() loop. If you are plotting things, the performance
bottleneck is not going to be in the loop.
Sometimes, we get too anal about avoiding for() loops.
Is there a way to get the name of the list in the loop body?
List=list(a='c',b='x',e='q')
for(x in List) { print(x) }
[1] c
[1] x
[1] q
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] Is there an variant of apply() that does not return anything?
On Thu, Nov 19, 2009 at 5:31 PM, Peng Yu pengyu...@gmail.com wrote: Is there a way to get the name of the list in the loop body? This was just discussed! See this thread: https://stat.ethz.ch/pipermail/r-help/2009-November/218919.html __ R-help@r-project.org mailing list 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.
Re: [R] Is there an variant of apply() that does not return anything?
On Nov 19, 2009, at 4:31 PM, Peng Yu wrote:
On Thu, Nov 19, 2009 at 4:27 PM, Marc Schwartz
marc_schwa...@me.com wrote:
On Nov 20, 2009, at 10:21 AM, Peng Yu wrote:
There are a few version of apply() (e.g., lapply(), sapply()). I'm
wondering if there is one that does not return anything but just
silently apply a function to the list argument.
For example, the plot function is applied to each element in
'alist'.
It is redundant to return anything from apply.
apply(alist,function(x){ plot each element of alist})
Just use a for() loop. If you are plotting things, the performance
bottleneck is not going to be in the loop.
Sometimes, we get too anal about avoiding for() loops.
Is there a way to get the name of the list in the loop body?
List=list(a='c',b='x',e='q')
for(x in List) { print(x) }
[1] c
[1] x
[1] q
Here is one approach to give you some insight into how to get the name
(as opposed to the object itself) of an argument passed to a function:
MyList - list(a = 1, b = 2, e = 3)
PlotFn - function(x)
{
# Get the name of the object passed as 'x' (eg. MyList)
Main - deparse(substitute(x))
for (i in seq(along = x))
{
plot(x[[i]], main = Main, ylab = names(x[i]))
}
}
# Set to pause between each graphic
par(ask = TRUE)
PlotFn(MyList)
Take note that the main title for each graphic will be MyList and
the y axis label for each, will be the name of each of the three
components in MyList (eg. a, b and e)
HTH,
Marc Schwartz
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