Displaying 20 results from an estimated 6000 matches similar to: "Retrieve distinct values within a whole data frame"
2010 Mar 25
4
Convert number to Date
Hello, I have a date value in excel: 1/4/2010 which in number format gives me
40182. When I read this with read.xls from R I get same 40182 so what I do
is that I use the as.Date() function but here is what the as.Date() function
returns me:
> as.Date(40182)
[1] "2080-01-06"
Why don't I get the same thing as in excel?
Thanks!
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Anna Lippel
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2010 Mar 03
5
filtering signals per day
Hello R lovers,
I have a vector of dates and signals. I want to filter the signals per day
in a way that only the first signal of the day remains like this:
Dates Signals Filtered Signal
2006-11-02 0 0
2006-11-02 1 1
2006-11-02 0 0
2006-11-02 1 0
2006-11-02 1
2010 Feb 12
3
Code working but too slow, any idea for how to speed it up ?(no loop in it)
Hello my friends,
here is a code I wrote with no loops on matrix that is taking too long (2
seconds and I call him 720 times --> 12 minutes):
mat1 and mat2 are both matrix with 103 columns and 164 rows.
sequence <- matrix(seq(1 : ncol(mat1)))
returns <- apply(sequence, 1, function, mat1= mat1, mat2 = mat2, day = 1)
function<- function(mat1, mat2, colNb, day){
2010 Jan 29
3
Applying a function on each columns of a matrix
Hello everyone, I have the following matrix
[,1] [,2] [,3] [,4]
[1,] 0.002809706 0.0063856960 0.0063856960 0.011749681
[2,] 0.004893124 0.0023118418 -0.0005122951 -0.014646465
[3,] 0.003547897 0.0063355297 0.0030410542 0.011403953
[4,] 0.004838299 -0.0040383645 -0.0090406831 -0.011027569
[5,] 0.035648755 0.0334815590 0.0380977404
2010 Jan 29
7
Simple question on replace a matrix row
Hello, I have a matrix mat1 of dim [1,8] and mat2 of dim[30,8], I want to
replace the first row of mat2 with mat1, this is what I do:
mat2[1,]<-mat1 but it transforms mat2 in a list I don't understand, I want
it to stay a matrix...
-----
Anna Lippel
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2010 Mar 17
2
Troubles on retrieving rownames
Hi guys, I am using the blp() function from RBloomberg package which returns
a matrix of prices with the columns corresponding to the security name and
the columns to the date. When I have a look at the matrix I can see the
rownames (dates) on the left of the prices but when I call the rownames()
function it returns me a NULL value. It worked perfectly until I had to
reinstall the RBloomberg
2010 Mar 11
2
Can't convert list to matrix properly
Hi guys, here is a list of names that I have:
MyList:
> myList<-list("A", "B","C","D")
> myList
[[1]]
[1] "A"
[[2]]
[1] "B"
[[3]]
[1] "C"
[[4]]
[1] "D"
I want to turn this list into a matrix of 1 row and 4 columns with those
four components (A, B, C, D) so here is what I do:
myDataFrame <-
2010 Mar 26
3
Using lapply with two lists
Hello guys,
I have a list L1 of matrix. I have another list L2 with the same number of
elements representing the row of the L matrix that I want to delete
(L1[[i]][-L2[[i]],]) but I can't do this with lapply as it iterates through
L1 (first argument) and not L2. Any idea?
-----
Anna Lippel
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2010 Mar 26
5
smart way to turn a vector into a matrix
Hello guys, I am working on a matrix which looks like this one:
> initialMatrix <-
> rbind(cbind(rep("A",3),seq(1,3)),cbind(rep("B",4),seq(1,4)),cbind(rep("C",3),seq(1,3)))
> initialMatrix
[,1] [,2]
[1,] "A" "1"
[2,] "A" "2"
[3,] "A" "3"
[4,] "B" "1"
[5,]
2010 Jan 26
3
Apply a function on an array with the parameter as an array
Hello R buddies, I want to apply a function on an array but for each element
of the array I want to use a different parameter, So here is how I tried to
enter the function:
apply(as.matrix(X),2, function, parameter1 = arrayOfParameter)
I put X as a matrix because it was initially an element of a list. It
returns me an array with the same length as X but with values that I don't
even
2009 Nov 16
5
Writing a data frame in an excel file
Hello, I am having trouble by using the write.table function to write a data
frame of 4 columns and 7530 rows. I don?t know if I should just use a
sep="\n" and change the .xls file into a .csv file. Thanks in advance
-----
Anna Lippel
new in R so be careful I should be asking a loooooooot of questions!:teeth:
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2010 Feb 03
2
Delete missing value rows from a matrix
Hi everyone,
I have a matrix with many Na's. Some rows contain some Na's and some others
are entirely composed of Na's. I want to delete the rows that are entirely
composed of Na's but not the other ones so I can't use a simple removeNA.
Has any one an idea?
-----
Anna Lippel
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2009 Nov 20
2
Problem at adding lines on a graphics with lines() function
Hello, I am trying to plot a graphic with many lines with the following
command:
plot(datas[1:n,1],datas[1:n,2],type="l",main="SP500 Prices and Moving
Averages",xlab="Date",ylab="Prices",col="black")
lines(datas[1:n,1],datas[1:n,3],type="l",col="green",lty="solid")
But I just see the first curve. I have tried it on
2010 Jan 28
2
Error on using lag function
Hello everyone, I have a vector P and I want to replace each of its missing
values by its next element, for example:
P[i] = NA --> P[i] = P[i+1]
To do this I am using the replace() and lag() functions like this:
P <- replace(as.ts(P),is.na(as.ts(P)),as.ts(lag(P,1)))
but here is the error that I get:
Warning message:
In NextMethod("[<-") :
number of items to replace is not a
2010 Feb 02
1
Build a matrix from another matrix by specifying the indexes
Hello R specialists,
I have a base vector called vBase with 102 elements. I have another vector
vec1 which elements are only part of vBase but is shorter. I transform vec1
so I get a vector with the same size as vBase and with each common element
on the same indexed row. If a value is missing in vec1 then I put a Na like
this:
vec1 vBase
Amsterdam Amsterdam
Na
2010 Apr 19
2
Using split and then unsplit
Hello everyone,
I use the split function splitting with the f function on a 3 columns and
more than 100 000 rows data frame. Once it's split I have a list of data
frames still with 3 columns and n rows. I manipulate those list elements and
get a list of data frames still with 3 columns but less rows. So when I
unsplit it, I get an error as I use the same factor function I used to split
( f in
2009 Nov 18
1
Creating an excel file and manipulating it from R
Hello everybody, I?ve been looking for a function that would create an excel
file in my working directory where I would write my dataframe but I only
found the functions to write or read in an existing file that you gave me on
my former post or on some websites. I can?t find either functions to
manipulate those datas: for example, I would like some lines to be red or
green according to their
2010 Feb 02
1
Finding the difference between two vectors
Hello everyone,
I have two vectors having only one element different:
vector1 vector2
vector1
TWC TWC
TWC
VFC TWX
NA
VIA/B VFC
VFC
2009 Nov 16
3
Error on reading an excel file
Hello everybody, here is the code I use to read an excel file containing two
rows, one of date, the other of prices:
library(RODBC)
z <- odbcConnectExcel("SPX_HistoricalData.xls")
datas <- sqlFetch(z,"Sheet1")
close(z)
It works pretty well but the only thing is that the datas stop at row 7530
and I don?t know why datas is a data frame that contains 7531 rows with the
2010 Jan 26
4
Error with toString
Hello there, I want to create a string from strings and numbers, here is my
code:
str <- "name" & toString(20)
but it returns me this error:
Error in toString(20) : could not find function ".jcall"
what did I do wrong? I couldn't find this error anywhere...
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