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Hi all, Thanks a lot for anyone's help in advance. I am trying to find a way to compute the day-to-day return (log return) from a n x r matrix containing, n different stocks and price quotes over r days. The time series of prices are already split by using unstack function. For the result, I would like to see a n x (r-1) matrix, where by each entry is the day-over-day return of

Hi all, I am just wondering if there is a more efficient way of merging two large datasets based on the values of multiple columns, some of which are not numerical. The default merge function in dataframe is very inefficient and the merge function in data.table seems to be faster, but it does not seem to allow keys that are not numerical in nature. Any other suggestion? Thanks a lot!

Hi, Just wondering for the SMA and EMA in package TTR, is it possible to me to code it so that, say if I need to calculate SMA (x, n=100), when the sample size is less than 100, it will give me the SMA (x, k) where k is the sample size of the data? Right now it only gives me an invalid n error. Thanks! [[alternative HTML version deleted]]

Hi :) I am a rookie about Linux , I try to run a software (used to be running on Windows ) on Linux , my questions are down below : 1)the software need s to replace some files after installation , but I can not find the actual path of it (simulation at c:\program files\anyi ) . 2)the software needs to access SQL server 2000 . can Wine solve my problems ? thanks for your help !!

Hi all, Say if I have a data table which consists of 4 column: itemID, location and price, which location is a text field and itemID and location together forms the primary keys. when I tried to run setkey (DT, itemID, location), I got the following message: Error in setkey (DT, itemID, location) : All keyed columns must be storage mode integer Is there any way I could define a non-numerical

...nswer provided by Mr. Peter Dalgaard,(use anova(model1,model2) I could not understand what model1 and model2 are supposed to referring to, which one is supposedly to be the full model and which one is to be the partial model? Or it does not matter? Thanks in advance for help from anyone! Regards, Anyi Zhu

Colleagues R 2.10.1 on a Mac I read in textfiles using readLines, then I process those files, then I use R to execute another program. Occasionally those files contain characters other than letter / numbers / routine punctuation marks. For example, a bullet (option-8 on a Mac) triggers the problem. Although R can read and process those characters, the other program cannot so I would like to