similar to: One silly question about "tapply output"

Dear R helpers, Thanks a lot for your earlier guidance esp. Mr Davind Winsemius Sir. However, there seems to be mis-communication from my end corresponding to my requirement. As I had mentioned in my earlier mail, I am dealing with a very large database of borrowers and I had given a part of it in my earlier mail as given below. For a given rating say "A", I needed to have the bad-wise

Dear R helpers Suppose I have a vector as vect_1 = c("AAA", "AA", "A", "BBB", "BB", "B", "CCC") vect_1_id = c(1:length(vect_1)) Through some process I obtain vect_2_id = c(2, 3, 7), then I need a new vector say vect_2 which will give me vect2 = ("AA", "A", "CCC")  i.e. I need the subset of

Dear R helpers I have following input f = c(257, 520, 110). I need to generate a decreasing sequence (decreasing by 100) which will give me an input (in a tabular form) like 257, 157, 57 520, 420, 320, 220, 120, 20 110, 10 I tried the following R code f = c(257, 520, 110) yy = matrix(data = NA, nrow = 3, ncol = 6) for (i in 1:3)      {      value = NULL      for (j in 1 : 6)           {

Hi I have a large credit portfolio (exceeding 50000 borrowers). For particular process I need to add up the exposures based on the bands. I am giving a small test data below. rating <- c("A", "AAA", "A", "BBB","AA","A","BB", "BBB", "AA", "AA", "AA", "A", "A",

Dear R helpers, xx = data.frame(country = c("USA", "UK", "Canada"), x = c(10, 50, 20), y = c(40, 80, 35), z = c(70, 62, 10)) > xx        country      x     y    z 1      USA        10    40  70 2      UK          50   80   62 3     Canada    20   35   10 I need to arrange this as a new data.frame as follows - country       type     values USA           

Dear R helpers Suppose I have a vector as vect1 = as.character(c("ABC", "XYZ", "LMN", "DEF")) > vect1 [1] "ABC" "XYZ" "LMN" "DEF" I want to reverse the order of this vector as vect2 = c("DEF", "LMN", "XYZ", "ABC") Kindly guide Regards Vincy [[alternative HTML

Dear R list, I have one very elementary question regrading correlation between two variables. x = c(44,46,46,47,45,43,45,44) y = c(44,43,41,41,46,48,44,43) > cov(x, y) [1] -2.428571 However, if I try to calculate the covariance using the formula as covariance = sum((x-mean(x))*(y-mean(y)))/8       # no of of paired obs. = 8 or     covariance = sum(x*y)/8-(mean(x)*mean(y)) gives

Dear R helpers I have a dataframe as df = data.frame(x = c(1, 14, 3, 21, 11), y = c(102, 500, 40, 101, 189)) > df    x   y 1  1 102 2 14 500 3  3  40 4 21 101 5 11 189 # Actually I am having dataframe having multiple columns. I am just giving an example. I need to subtract all the rows of df by the first row of df i.e. I need to subtract each element of 'x' column by 1. Likewise I

Hi, I have one basic doubt. Suppose X ~ N(50,10). I need to calculate Probability X = 50. dnorm(50, 50, 10) gives me [1] 0.03989423 My understanding is (which is bit statistical or may be mathematical) on a continuous scale, Probability of the type P(X = .....) are nothing but 1/Infinity i.e. = 0. So as per my understanding P(X = 50) should be 0, but even excel also gives 0.03989422. Obviously

Dear R helpers, Suppose I have following data.frame. df <- data.frame(category = c("treat_A", "treat_A", "treat_A", "treat_A", "treat_A", "treat_A", "treat_A", "treat_A", "treat_B", "treat_B", "treat_B", "treat_B", "treat_B", "treat_B",

Dear R helpers, I have recently installed R version 2.15.0 I just wanted to calculate mean(16, 18) Surprisingly I got answer as > mean(16, 18) [1] 16 > mean(18, 16) [1] 18 > mean(14, 11, 17, 9, 5, 18) [1] 14 So instead of calculating simple Arithmetic average, mean command is generating first element as average. I restarted the machine, changed the machine, but still the

Dear R helpers Wish you all a very Happy and Prosperous New Year 2011. I have following query. country = c("US", "France", "UK", "NewZealand", "Germany", "Austria", "Italy", "Canada") Through some other R process, the result.csv file is generated as result.csv      var1   var2  var3  var4    var5    var6   var7  

Dear R list As suggested by Prof Brian Ripley, I have tried to read acf literature. The main problem is I am not the statistician and hence have some problem in understanding the concepts immediately. I came across one literature (http://www.stat.nus.edu.sg/~staxyc/REG32.pdf) on auto-correlation giving the methodology. As per that literature, the auto-correlation is arrived at as per following.

Dear R helpers Suppose, x = c(0,  1,  2,  3) y = c("A", "B", "C", "D") z = c(1, 3) For given values of z, I need to the values of y. So I should get "B" and "D". I tried doing y[x][z] but it gives > y[x][z] [1] "A" "C" Kindly guide. Regards Vincy [[alternative HTML version deleted]]

Dear R helpers, I have one basic doubt about the value of pi. In school, we have learned that pi = 22/7 (which is = 3.142857). However, if I type pi in R, I get pi = 3.141593. So which value of pi should be considered? Regards Vincy [[alternative HTML version deleted]]

Dear R helpers Suppose x  <- c(1:3) y  <- matrix(1:12, ncol = 3, nrow = 4) > y      [,1] [,2] [,3] [1,]    1    5    9 [2,]    2    6   10 [3,]    3    7   11 [4,]    4    8   12 I wish to multiply 1st column of y by first element of x i.e. 1, 2nd column of y by 2nd element of x i.e. 2 an so on. Thus the resultant matrix should be like > z      [,1]   [,2]    [,3] [1,]    1   

Dear R helpers, (At the outset I sincerely apologize if I have not put forward my following query properly, though I have tried to do so.) Following is a curtailed part of my R - code where I am trying to generate say 100 random no.s for each of the products under consideration. library(plyr) n = 100 my_code = function(product, output_avg, output_stdev)     { BUR_mc = rnorm(n, output_avg,

Dear R helpers, I have one trivial problem while writing an output file in csv format. I have two dataframes say df1 and df2 which I am reading from two different csv files. df1 has column names as date, r1, r2, r3 while the dataframe df2 has column names as date, 1w, 2w. (the dates in both the date frames are identical also no of elements in each column are equal say = 10). I merge these

Dear R helpers, Suppose I have stock returns data of say 1500 companies each for say last 4 years. Thus I have a matrix of dimension say 1000 * 1500 i.e. 1500 columns representing companies and 1000 rows of their returns. I need to find the correlation matrix of these 1500 companies. So I can find out the correlation as cor(returns) and expect to get 1500 * 1500 matrix. However, the process

Dear 'HTH' R friends I have a small dataframe as given below. I need to sort this database based on date in a decending order. I am not sure whether I have defined the date column in a proper format. mydat<-data.frame(date = (c("1/31/2010", "2/28/2010", "3/31/2010", "4/30/2010", "5/31/2010", "6/30/2010",