[R] For loop with if else statement
Hans,
I think your problem is that you don't use the variable which takes different
values in your if statement your i changes values and has really nothing
to do with your x variable (except the length part ). Also all the other
variables need to be declared somehow - otherwise how can you store values in
them???
So your first code may be something like that:
t=c(1,2)
for(i in 1:length(t)){
if (i==1) t[i]=i+1 else t[i]=i
}
t[1] 2 2
and your second code:
a = c(1,2)
b=c(1,2)for(i in 1:2){if (i==1){a[i]=ib[i]=i-1} else{
a[i]=i+1b[i]=i}c-list(a=a,b=b)}
c$a[1] 1 3 c$b[1] 0 2
Also when you have only 2 possible values for i i don't think the second if
is necessary. I hope this helps a little, although my explanation is not
necessarily the best.
Monica
-- Message: 16Date: Tue, 4 Sep 2007 15:59:54
+0200From: Hans Ole ?rka [EMAIL PROTECTED]Subject: [R] For loop with if else
statementTo: 'r-help@stat.math.ethz.ch'
r-help@stat.math.ethz.chMessage-ID:[EMAIL PROTECTED]Content-Type:
text/plain; charset=iso-8859-1 Hi,I try to make a simple for loop with a if
else statement (First example - Below) and extend it to a more complex loop
(Second example). However, my results #First example:x=c(1,2)t=for(i in
1:length(x)){if (x==1){a=x+1}elseif (x==2){a=x}} Returned from R:Warning
messages:1: the condition has length 1 and only the first element will be
used in: if (x == 1) {2: the condition has length 1 and only the first
element will be used in: if (x == 1) { t[1] 2 3 However, the result i had
liked to get was t=c(2,2) i.e. using the first function (a=x+1) for x[1] and
(a=x) for x[2]. I can remove the Warnings by making: if (x[i]==1) etc. but this!
do not make the results any better. #Second example:x=c(1,2)t-for(i in
1:length(x)){if (x==1){a=xb=x-1}elseif (x==2){a=x+1b=x}b-list(a=a,b=b)}
Returned from R:Warning messages:1: the condition has length 1 and only the
first element will be used in: if (x == 1) {2: the condition has length 1 and
only the first element will be used in: if (x == 1) { t$a[1] 1 2 $b[1] 0 1 The
result i like to get are $a =c(1,3) and $b=c(0,2) Probably there are couple of
things that I do wrong and I appreciate all help!
_
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[R] For loop with if else statement
Hi,
I try to make a simple for loop with a if else statement (First example -
Below) and extend it to a more complex loop (Second example). However, my
results
#First example:
x=c(1,2)
t=for(i in 1:length(x)){
if (x==1){a=x+1}else
if (x==2){a=x}
}
Returned from R:
Warning messages:
1: the condition has length 1 and only the first element will be used in: if
(x == 1) {
2: the condition has length 1 and only the first element will be used in: if
(x == 1) {
t
[1] 2 3
However, the result i had liked to get was t=c(2,2) i.e. using the first
function (a=x+1) for x[1] and (a=x) for x[2]. I can remove the Warnings by
making: if (x[i]==1) etc. but this do not make the results any better.
#Second example:
x=c(1,2)
t-for(i in 1:length(x)){
if (x==1){
a=x
b=x-1}else
if (x==2){
a=x+1
b=x}
b-list(a=a,b=b)
}
Returned from R:
Warning messages:
1: the condition has length 1 and only the first element will be used in: if
(x == 1) {
2: the condition has length 1 and only the first element will be used in: if
(x == 1) {
t
$a
[1] 1 2
$b
[1] 0 1
The result i like to get are $a =c(1,3) and $b=c(0,2)
Probably there are couple of things that I do wrong and I appreciate all help!
__
R-help@stat.math.ethz.ch 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] For loop with if else statement
On 9/4/2007 9:59 AM, Hans Ole Ørka wrote:
Hi,
I try to make a simple for loop with a if else statement (First example -
Below) and extend it to a more complex loop (Second example). However, my
results
#First example:
x=c(1,2)
t=for(i in 1:length(x)){
if (x==1){a=x+1}else
if (x==2){a=x}
}
Returned from R:
Warning messages:
1: the condition has length 1 and only the first element will be used in:
if (x == 1) {
2: the condition has length 1 and only the first element will be used in:
if (x == 1) {
t
[1] 2 3
However, the result i had liked to get was t=c(2,2) i.e. using the first
function (a=x+1) for x[1] and (a=x) for x[2]. I can remove the Warnings by
making: if (x[i]==1) etc. but this do not make the results any better.
x is a vector of length 2. Using a = x + 1 means that the entire vector
a will be replaced by the entire vector x. You need to index each entry
each time you use it, i.e.
if (x[i] == 1) a[i] - x[i] + 1
else if (x[i] ==2]) a[i] - x[i]
or more simply, throw away the loop, and use the ifelse function:
a - ifelse( x == 1, x + 1,
ifelse( x == 2, x,
NA) )
(where I've used NA for the case where x is neither 1 nor 2.)
Duncan Murdoch
#Second example:
x=c(1,2)
t-for(i in 1:length(x)){
if (x==1){
a=x
b=x-1}else
if (x==2){
a=x+1
b=x}
b-list(a=a,b=b)
}
Returned from R:
Warning messages:
1: the condition has length 1 and only the first element will be used in:
if (x == 1) {
2: the condition has length 1 and only the first element will be used in:
if (x == 1) {
t
$a
[1] 1 2
$b
[1] 0 1
The result i like to get are $a =c(1,3) and $b=c(0,2)
Probably there are couple of things that I do wrong and I appreciate all help!
__
R-help@stat.math.ethz.ch 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.
__
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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.
