Displaying 20 results from an estimated 4000 matches similar to: "are arithmetic comparison operators binary?"
2009 Mar 18
2
incoherent conversions from/to raw
i wonder about the following examples showing incoherence in how type
conversions are done in r:
x = TRUE
x[2] = as.raw(1)
# Error in x[2] = as.raw(1) :
# incompatible types (from raw to logical) in subassignment type fix
it seems that there is an attempt to coerce the raw value to logical
here, which fails, even though
as.logical(as.raw(1))
# TRUE
likewise,
x[2]
2009 Mar 18
2
incoherent conversions from/to raw
i wonder about the following examples showing incoherence in how type
conversions are done in r:
x = TRUE
x[2] = as.raw(1)
# Error in x[2] = as.raw(1) :
# incompatible types (from raw to logical) in subassignment type fix
it seems that there is an attempt to coerce the raw value to logical
here, which fails, even though
as.logical(as.raw(1))
# TRUE
likewise,
x[2]
2009 Mar 19
8
function question
Dear R Gurus:
I read somewhere that functions are considered vectors.
Is this true, please?
thanks
Edna Bell
2009 Mar 23
1
incoherent treatment of NULL
somewhat related to a previous discussion [1] on how 'names<-' would
sometimes modify its argument in place, and sometimes produce a modified
copy without changing the original, here's another example of how it
becomes visible to the user when r makes or doesn't make a copy of an
object:
x = NULL
dput(x)
# NULL
class(x) = 'integer'
# error: invalid
2008 Oct 26
4
odd behaviour of identical
given what ?identical says, i find the following odd:
x = 1:10
y = 1:10
all.equal(x,y)
[1] TRUE
identical(x,y)
[1] TRUE
y[11] = 11
y = y[1:10]
all.equal(x,y)
[1] TRUE
identical(x,y)
[1] FALSE
y
[1] 1 2 3 4 5 6 7 8 9 10
length(y)
[1] 10
looks like a bug.
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system
2008 Nov 17
4
functional (?) programming in r
the following is a trivialized version of some functional code i tried
to use in r:
(funcs = lapply(1:5, function(i) function() i))
# a list of no-parameter functions, each with its own closure environment,
# each supposed to return the corresponding index when applied to no
arguments
sapply(funcs, function(func) func())
# supposed to return c(1,2,3,4,5)
there is absolutely nothing unusual in
2009 May 13
3
where does the null come from?
m = matrix(1:4, 2)
apply(m, 1, cat, '\n')
# 1 2
# 3 4
# NULL
why the null?
vQ
2009 Jan 02
1
[Fwd: Re: [R] Randomly remove condition-selected rows from a matrix]
Following Duncan's suggestion, I forward the below to R-devel.
vQ
-------- Original Message --------
Subject: Re: [R] Randomly remove condition-selected rows from a matrix
Date: Fri, 02 Jan 2009 10:34:52 -0500
From: Duncan Murdoch <murdoch at stats.uwo.ca>
To: Wacek Kusnierczyk <Waclaw.Marcin.Kusnierczyk at idi.ntnu.no>
CC: R help <R-help at stat.math.ethz.ch>
2009 Apr 21
8
incorrect output and segfaults from sprintf with %*d (PR#13667)
Full_Name: Wacek Kusnierczyk
Version: 2.10.0 r48365
OS: Ubuntu 8.04 Linux 32bit
Submission from: (NULL) (129.241.110.141)
sprintf has a documented limit on strings included in the output using the
format '%s'. It appears that there is a limit on the length of strings included
with, e.g., the format '%d' beyond which surprising things happen (output
modified for conciseness):
2009 Mar 15
4
primitives again
Dear R Gurus:
How do I find the functions which are primitives, please?
Thanks,
Edna Bell
2008 Jun 20
5
Programming Concepts and Philosophy
I am wondering if people on the list could recommend books that they
have found helpful about programming concepts and style? I often find
that students write R programs by copying existing code but could really
benefit from the understanding of more general programming ideas. An
example would be to avoid writing functions which attempt to modify
their parameters. Another principle would be
2008 Nov 30
6
Regex: workaround for variable length negative lookbehind
Hi all
I have the following regular expression problem: I want to find
complete elements of a vector that end in a repeated character but
where the repetition doesn't make up the whole word. That is, for the
vector vec:
vec<-c("aaaa", "baaa", "bbaa", "bbba", "baamm", "aa")
I would like to get
"baaa"
"bbaa"
2009 Feb 25
8
learning R
I was wondering why the following doesn't work:
> a=c(1,2)
> names(a)=c("one","two")
> a
one two
1 2
>
> names(a[2])
[1] "two"
>
> names(a[2])="too"
> names(a)
[1] "one" "two"
> a
one two
1 2
I must not be understanding some basic concept here.
Why doesn't the 2nd name change to
2009 Feb 25
8
learning R
I was wondering why the following doesn't work:
> a=c(1,2)
> names(a)=c("one","two")
> a
one two
1 2
>
> names(a[2])
[1] "two"
>
> names(a[2])="too"
> names(a)
[1] "one" "two"
> a
one two
1 2
I must not be understanding some basic concept here.
Why doesn't the 2nd name change to
2009 Apr 02
2
actual argument matching does not conform to the definition (PR#13634)
Full_Name: Wacek Kusnierczyk
Version: 2.10.0 r48269
OS: Ubuntu 8.04 Linux 32 bit
Submission from: (NULL) (129.241.199.164)
In the following example (and many other cases):
quote(a=1)
# 1
the argument matching is apparently incorrect wrt. the documentation (The R
Language Definition, v 2.8.1, sec. 4.3.2, p. 23), which specifies the following
algorithm for argument matching:
1. Attempt to
2009 Mar 30
1
duplicated fails to rise correct errors (PR#13632)
Full_Name: Wacek Kusnierczyk
Version: 2.8.0 and 2.10.0 r48242
OS: Ubuntu 8.04 Linux 32 bit
Submission from: (NULL) (129.241.110.161)
In the following code:
duplicated(data.frame(), incomparables=NA)
# Error in if (!is.logical(incomparables) || incomparables)
.NotYetUsed("incomparables != FALSE") :
# missing value where TRUE/FALSE needed
the raised error is clearly not the
2009 Jan 18
8
regex -> negate a word
Dear all,
let's assume I have a vector of character strings:
x <- c("abcdef", "defabc", "qwerty")
What I would like to find is the following: all elements where the word
'abc' does not appear (i.e. 3 in this case of 'x').
Since I am not really experienced with regular expressions, I started
slowly and thought I find all word were
2008 Nov 10
6
Variable passed to function not used in function in select=... in subset
Hello!
I have the problem that in my function the passed variable is not used, but the variable name of the dataframe itself?- difficult to explain, but an easy example:
TestFunc<-function(df, group) {
??? print(names(subset(df, select=group)))
}
df1<-data.frame(group="G1", visit="V1", value=0.9)
TestFunc(df1, c("group", "visit"))
Result:
[1]
2009 Mar 22
5
If statement generates two outputs
Hi,
How do I tell an if statement to generate two seperate outputs.
E.g If X>5 I want to create df1 and df2:
if (X>5) {df1<-c(4,5,6,7,8) AND df2<-c(9,10,11,12,13)}
Thanks,
James
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2008 Jun 18
1
strsplit and the empty string
Hello,
I am wondering about the behaviour of strsplit. When the pattern
matches the beginning of the search string, the mepty string is added to
the result, but that's not the case when the pattern matches the end of
the search string:
strsplit(" hello dolly ")
[1] "" "hello" "dolly"
The man for strsplit explains the algorithm:
"
The algorithm