i param in "for" loop does not takes zeros?

The for loop is not ignoring the zero at all, but the assignment is,
since R indexes starting at 1, not zero.
sim <- c()
sim[0] <- 1
sim
numeric(0)

To run this loop this way, you need to add one to the index:
for ( i in 0:5 )
  sim[i+1] <- dbinom(i, 5, p)

However, you'd be better off passing your vector of values directly to
dbinom():
dbinom(0:5, 5, p)
[1] 0.32768 0.40960 0.20480 0.05120 0.00640 0.00032
all(dbinom(0:5, 5, p) == sim)
[1] TRUE

Cheers,
Rich
Hi all

Is there any reason why the parameter i in a "for" loop ignores a value of
zero?  For example

sim=c()
p=.2
for(i in 0:5)
 {sim[i]=dbinom(i,5,p)
 }

sim
[1] 0.40960 0.20480 0.05120 0.00640 0.00032

In this example the quantile i= 0 was ignored since
dbinom(0,5,p)
[1] 0.32768

The same behaviour occurs if I use a while loop to perform the same
calculation:
sim=c()
p=.2
i=0
while(i <6)
 {sim[i]=dbinom(i,5,p)
 i=i+1
 }
sim
[1] 0.40960 0.20480 0.05120 0.00640 0.00032

How can I perform a loop passing a zero value parameter?  I know I can use
an if statement for i<=0 but I was wondering why the loop is ignoring the
zero value.

Many thanks!

Francisco

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Rich FitzJohn
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                      You are in a maze of twisty little functions, all alike

i param in "for" loop does not takes zeros?

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