problem with for()

Simone Gabbriellini <ogabbrie at tin.it> writes:

Dear list,
can someone tell me why this two pieces of code give me the same  
results?

for(i in 0:5){ sum[i] = i }
sum

[1] 1 2 3 4 5

for(i in 1:5){ sum[i] = i }
sum

[1] 1 2 3 4 5

shouldn't the first one be

0 1 2 3 4 5

No. Indexing starts at 1 in R.

Next, figure out this:

sum=0
for(i in 5:-5){ sum[i] = i }
sum

[1] -5 -5 -5 -5 -4