similar to: .net and R

Hello,   I tried to use a variable to refer colname, but I got error, could anyone give me advice?   >df=data.frame(cbind(AB=1:3,AC=3:5)) > df$AC [1] 3 4 5 > df$paste("A","C",sep="") Error: attempt to apply non-function thanks Jian   [[alternative HTML version deleted]]

Hi,   I have a matrix. >a<-cbind(c("a","b","a"),c(4,3,6))      [,1] [,2] [1,] "a"  "4" [2,] "b"  "3" [3,] "a"  "6" I want to remove rows in matrix a whose first column has frequency less than 2. in about example matrix a becomes      [,1] [,2] [1,] "a"  "4" [2,] "a" 

Hello,   I have a dataframe: dd <- data.frame(b = c("chr2", "chr1", "chr15", "chr13"),         x = c("A", "D", "A", "C"), y = c(8, 3, 9, 9),         z = c(1, 1, 1, 2))   >dd       b x y z 1  chr2 A 8 1 2  chr1 D 3 1 3 chr15 A 9 1 4 chr13 C 9 2 Now I want to sort them according column "b", but only its

Hello,   I could not find a clear solution for the follow question. please allow me to ask. thanks   mynames=cbind(c('a','b'),c(11,22)) lst=list(a=c(1,2), b=5) now I try to combine mynames and lst: a  1  11   a  2  11 b  5  22   thanks jian   [[alternative HTML version deleted]]

Hi,   how to remove levels that have less than a specific number such as 2. i.e..   > f<-as.factor(c("a","b","a")) > f [1] a b a Levels: a b I want to remove level b because level b has less than 2. > f [1] a a Levels: a   [[alternative HTML version deleted]]

Hi there, how can I test every element in a vector whether appears in another vector? such as a<-c("aa", "bb", "ff", "cc") b <-c("oo","jj","bb","cc") somefunction(a,b) gives [False, True, False, True] thanks yuan jian [[alternative HTML version deleted]]

Hello, I have a simple question: I want to list numbers 1:k, but if k <1, I hope nothing listed. how should we do? k=2 for (i in 1:k)  print(i) [1] 1    # <-correct [1] 2 k=0 for (i in 1:k) print(i) [1] 1      #<---- wrong [1] 0   thanks jian [[alternative HTML version deleted]]

Hi,   it seems a simple problem, but I can not find a clear way. I have a list: lst=list(m=c('a','b','c'),n=c('c','a'),l=c('a','bc')) > lst $m [1] "a" "b" "c" $n [1] "c" "a" $l [1] "a"  "bc" how can I get list elements that include a given subset? for example, for given

Hello R experts, can you tell me a simple way to convert a charactor matrix to numeric matrix? if I use as.numeric, the matrix is converted to a vector. a<-cbind(c("23","54","65"),c("1","2","3")) a      [,1] [,2] [1,] "23" "1" [2,] "54" "2" [3,] "65" "3"  as.numeric(a)

Hi, if I know the colnames x and y in the following example, I can easily to do lm. tmp <- data.frame(x=c(1,1.2),y=c(1,2)) lm(y ~ x, data=tmp) when the colnames are variable, what should I do? for example colnames(tmp)[1] <- paste("aa",1,sep="_") lm(y ~ paste("aa",1,sep="_"), data = tmp) it gives me error. [[alternative HTML version

hi, can anyone tell me how to merge a vector and a matrix? > v=c(1,4,2) > names(v)=c("e","r","t") > m=matrix(c("r","t","r","s","e",5,6,7,8,9),nr=5) > colnames(m)=c("c1","c2") I want to do like merge(v, m, by.x="names",by.y="c1") I got error Error in fix.by(by.x, x) :

Hello, how to merge a data.frame and a matrix by one column in the data.frame and rownames of the matrix? df <- data.frame(col1=c("kk","yy","kk"),col2=c(6,4,3)) > df   col1 col2 1   kk    6 2   yy    4 3   kk    3 m<-matrix(c(3,8,56,9), nrow=2, dimnames = list(c("aa","kk"),c("col1","col2"))) > m    col1 col2 aa   

Hello, I have a data.frame: name    col1    col2    col3    col4 AA    23    54    0.999    0.78 BB    123    5    1    0.99 AA    203    98    0.79    0.99 I want to get mean value data.frame in terms of name: name    col1    col2    col3    col4 AA    113.0000  76.0000   0.8945   0.8850 BB    123.00   5.00   1.00   0.99 I tried to use by function: >aa<-by(test[,2:5], feature, mean)

Hi R-experts, I try to find a way to transfer a matrix to a data.frame that is used as input of aov. can you give me advice for that? >mdat <- matrix(c(1,2,3, 11,12,13), nrow = 2, ncol=3, byrow=TRUE, dimnames = list(c("row1", "row2"), c("Col1", "Col2", "Col3"))) >mdat      Col1 Col2 Col3 row1    1    2    3 row2   11   12   13 ===>

Hi R experts. how can I average two sets of columns? dd <- data.frame(b = c("chr2", "chr1", "chrY", "chr13", "chrX"),         w=11:15, x = 1:5, y = c(8, 3, 9, 9,7),        z = c(1, 1, 1, 2, 8)) expected result for mean(w,x) and mean(y,z) is 1  chr2 6  4.5 2  chr1 7  2 3  chrY 8  5 4 chr13 9  5.5 5  chrX 10 7.5 Yu [[alternative

Hi there, I checked google for aov. usually one uses summary to see whether the p-value is small. but I want to put aov in my script. how can I get the p-value, (0.1115, 0.6665, 0.6665 in the following example)? thanks YU > datafilename="http://personality-project.org/r/datasets/R.appendix2.data" > data.example2=read.table(datafilename,header=T) > aov.ex2 =

Hello,   is there a simple way to give all combinations for a given vector:   v<-c("a","b","c")   combination(v,v) becomes "aa","ab","ac","bb","bc","cc'   combination(v,v,v) becomes "aaa","aab","aac","abb",......     [[alternative HTML version deleted]]

Hi, I am using plot to show scatter points in 2_D. in my data, there is no data between -1 and +1 in x-axis. I want to skip this region, i.e. x axis becomes [-Inf:-1, 1:Inf]. can any one tell me how to do? YU [[alternative HTML version deleted]]

Hello there, I got a small problem about logical calculation: we can get a sequene from a+b as below: > a<-c(1,2) > b<-c(3,4) > a+b [1] 4 6 but when the sequences are logical. (I want to get (True,False) && (True, True) ==> (True, False), but when I do as below. > e<-c(T,T) > f<-c(F,T) > e [1] TRUE TRUE > f [1] FALSE TRUE >

Hello,   ###  I created two classes "A" and "B". "A" is the superclass of "B".   setClass("A", representation(s1="numeric"),prototype=prototype(s1=8)) setClass("B",contains="A",representation(s2="character"),prototype=list(s2="hi")) myA=new("A") myB=new("B")   ####  I created