Neil Gupta wrote:
Hello,
I have quite a simple problem that I believe can be solved quite easily. I
have a dataframe as such:
Symbol Date Time Exchange TickType ReferenceNumber Price Size
1 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916044 13387 9
2 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916045 13388 1
3 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916054 13387 9
4 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916055 13388 1
5 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916533 13386 39
6 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916534 13388 1
I wanted the average of the B's and A's. I wrote this to perform that.
NPrice <-
(YM1207$Price[which(YM1207$TickType=="B")]+YM1207$Price[which(YM1207$TickType=="A")])/2
head(NPrice)
[1] 13387.5 13387.5 13387.0 13386.5 13386.5 13387.0
Now since NPrice is much smaller than the original dataframe, YM1207 I can
not just add NPrice to the set.
How can I put each of those averages back into their corresponding row? I
would even prefer repeating the values for A's as well..
I would like to do it as such..
Symbol Date Time Exchange TickType ReferenceNumber Price Size
NPrice
1 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916044 13387
9 13387.5
2 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916045 13388
1 13387.5
3 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916054 13387
9 13387.5
4 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916055 13388
1 13387.5
5 3:YMZ7.EC 12/03/2007 08:30:00 EC B 83916533 13386
39 13387.0
6 3:YMZ7.EC 12/03/2007 08:30:00 EC A 83916534 13388
1 13387.0
What can be assumed here? If the alternating B,A pattern is consistent,
I'd go for (something like)
N <- nrow(YM1207)
ix <- gl(N/2,2)
YM1207$NPrice <- ave(YM1207, ix)
--
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