The problem might be simple, but I cant solve it:
I got numeric vector, i need to compare its maximum/2 with each member except its maximum and if all these comparisons are FALSE , a=a+1.
I got these:
comp=c(6.674971, 11.208241, 18.296459, 5.165752, 123.000000)
a=0
if (max(comp)/2<comp[comp < max(comp)]){
a=a+1
}
a
Thank you in advance.
The condition is true if :
sum(2*comp > max(comp)) ==1
In this case , I would write it like this without using ìf:
a <- (sum(2*comp > max(comp)) ==1) + 1
I don't know if you want to add 1 every time you find a item bigger than max/2, which is what I am showing you. In case you want all to be false, add this line at the end.
if (a>0)
a=1;
I think this will work, haven't compiled it because here I don't have R compiler, but this is the idea:
comp=c(6.674971, 11.208241, 18.296459, 5.165752, 123.000000)
a=0
temp=comp/max(comp)
for (n in 1:length(comp))
{ if ((temp(i)>max(comp)/2)&&(temp(i)!1))
a=a+1
}
Hope it helps.
Related
Hi I have the following code in Scilab:
>Tc=0;
>Tm=1;
>Tf=1800;
>t=(Tc:1:Tf)';
where t is a vector of 1800 components.
And I am asked to do a piecewise function that satisfies certain conditions,
My first try was to do something on the line of
> function vg=simula_vg(t,Tcg,Tfg,Ag)
> if (t<Tcg | t>Tfg) then
> vg=0;
> else
> vg=Ag*Ag*(1-cos(2*%pi*(t-Tcg)/(Tfg-Tcg)));
>end
>endfunction
But it doesnt work as I am asking it to compare vector and scalars.
Then I tried to write this
>for i=[Tc:1:Tf]
>function vg=simula_vg(t,Tcg,Tfg,Ag)
> vg(t<Tcg)=0
>vg(t>Tfg)=0
>vg((Tcg<=t)&(t<=Tfg))=sin(t(i))
>endfunction
>end
But I doesnt work either and I have run out of ideas, is there anything else I can do? All the variables are well defined
>vm=10;
>Ag=2;
>Tcg=200;
>Tfg=400;
>Ar=2;
>Tcr=1000;
>Tfr=1500;
>As=2;
>fs=0.0008;
>h=20;
>d=0.6;
There are more because there are more functions similar to that one that I have to define and I dont know how. Any suggestions on how to do it?
You can do it like this, where the zero values are defined afterwards:
function vg=simula_vg(t,Tcg,Tfg,Ag)
vg=Ag*Ag*(1-cos(2*%pi*(t-Tcg)/(Tfg-Tcg)));
vg(t<Tcg|t>Tfg)=0;
endfunction
Ag=2;
Tcg=200;
Tfg=400;
Tc=0;
Tm=1;
Tf=1800;
t=Tc:1:Tf;
vg = simula_vg(t,Tcg,Tfg,Ag);
plot(t,vg)
Greetings I am getting an error of
Error in if (nrow(pair) == 0) { :argument is of length zero
I have checked the other answers but do not seem to work on a variable like mine. Please check code below, please assist if you can.
pair<-NULL
if(exists("p.doa.ym")) pair <- rbind(pair, p.doa.ym[,1:2])
if(exists("p.doa.yd")) pair <- rbind(pair, p.doa.yd[,1:2])
if(nrow(pair) == 0) {
print("THERE ARE NO MATCHES FOR TODAY. STOP HERE")
quit()
}
Since you set pair=NULL and then it might happen that pair stays null if those two if statements are not true, you either need to check if pair is null first, or you could set pair to an empty data frame, or something else.
One option:
if (!is.null(pair)) {
if (nrow(pair)==0) {
# your code
}
}
Another option:
pair=data.frame()
# your code
I'm fairly new to R and I have not been working with functions in R before.
I want to write a program/algorithm (using R) that calculates the square root of a given positive number.
Would anyone mind take the time to give me an example of how this can be achieved?
Thanks a lot in advance!
UPDATE
posNum_to_squaRtNum <- function(posNum) {
if (posNum <= 0)
print("Due to mathmatical principles you have to input a positive number")
else
squaRtNum <- sqrt(posNum)
return(squaRtNum)
}
When I insert a negative number in the function, the output is my print PLUS the error: "Error in posNum_to_squaRtNum(-1) : object 'squaRtNum' not found." It should not go on to the else statement, if the if statement is fulfilled right?
You should wrap your if conditions in brackets:
posNum_to_squaRtNum <- function(posNum) {
if (posNum <= 0) {
print("Due to mathmatical principles you have to input a positive number")
} else {
squaRtNum <- sqrt(posNum)
return(squaRtNum)
}
}
I am trying to implement following algorithm in R:
Iterate(Cell: top)
While (top != null)
Print top.Value
top = top.Next
End While
End Iterate
Basically, given a list, the algorithm should break as soon as it hits 'null' even when the list is not over.
myls<-list('africa','america south','asia','antarctica','australasia',NULL,'europe','america north')
I had to add a for loop for using is.null() function, but following code is disaster and I need your help to fix it.
Cell <- function(top) {
#This algorithm examines every cell in the linked list, so if the list contains N cells,
#it has run time O(N).
for (i in 1:length(top)){
while(is.null(top[[i]]) !=TRUE){
print(top)
top = next(top)
}
}
}
You may run this function using:
Cell(myls)
You were close but there is no need to use for(...) in this
construction.
Cell <- function(top){
i = 1
while(i <= length(top) && !is.null(top[[i]])){
print(top[[i]])
i = i + 1
}
}
As you see I've added one extra condition to the while loop: i <= length(top) this is to make sure you don't go beyond the length of the
list in case there no null items.
However you can use a for loop with this construction:
Cell <- function(top){
for(i in 1:length(top)){
if(is.null(top[[i]])) break
print(top[[i]])
}
}
Alternatively you can use this code without a for/while construction:
myls[1:(which(sapply(myls, is.null))[1]-1)]
Check this out: It runs one by one for all the values in myls and prints them but If it encounters NULL value it breaks.
for (val in myls) {
if (is.null(val)){
break
}
print(val)
}
Let me know in case of any query.
Inside of double loop I create subset of data for each combination of Tv stations with months which is done by loops. For example I have monthsnumbers 7,8,9 and stations A,B,C. It happens that for Month 9 there is no station C.
Then subset is empty and function throws and error of no possible aggregation.
So as you can see I tried to use if statement that if there are 0 rows don't continue with the code but go on to the next loop.
But I still get the same error fck. message
can you please navigate me ?
for (Mesic in monthnumbers){
for (Stanica in TVstations){
Client<-data[data$month ==Mesic & data$Channel_group1 ==Stanica & data$Brand == brand, ]
if (nrow(Client)!=0)
###some code
Client_AGG<-aggregate(formula= Client$BUYING_GRPs ~ Client$Brand,data= Client,FUN = sum)
###some code
}
}
}
Like Gregor commented, there is likely a better way of going about this.
But a quick patch might be to put the error check before the Client<- line because that's where it's looking for a channel that doesn't exist. Check if data$Channel_group1 == Stanica even exists before trying to get data from it.
Another option using for loops is to cycle through what you know is there with something like this:
subsetindex <- unique(data[ ,c('month','Channel_group1')])
for(i in 1:nrow(subsetindex)){
Client<-data[data$month ==subsetindex[i,'month'] & data$Channel_group1 ==subsetindex[i,'Channel_group1'] & data$Brand == brand, ]
#other code
}