Correct Syntax for a Loop
ebashi wrote:
I'll appreciate if some one can help me with the following loop. This is the logic of the loop, if we have the following data;
x.df
x.dif
. .
. .
102 0.00
103 0.42
104 0.08
105 0.00
106 0.00
107 0.00
108 -0.16
109 -0.34
110 0.00
111 -0.17
112 -0.33
113 0.00
114 0.00
115 0.00
116 0.33
117 0.17
118 0.00
. .
. .
I'm trying to find i's where
for (i in 2:length(x.dif))
if (x.dif[i-1]<=0 and x.dif[i]>0 and x.dif[i+2]>0)
Solution to the question: a) you cannot loop to length(x.dif), x.dif[i+2] does not exist for i==length(x.dif). b) Use && instead of "and" in this case c) vector operations are much mor Hint: If you lengthen the vectors appropriately, you can apply the comparisons vectorized rather than in a loop... Uwe Ligges
it would return i+2 to me, How can I turn this to a right format as a loop.(I can't figure out the syntax) Cheers, Sean
______________________________________________ R-help at 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