Displaying 20 results from an estimated 3000 matches similar to: "Maintaining Column names while writing csv file."
2011 Jan 25
4
Subtracting elements of data.frame
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
2010 Dec 31
3
Changing column names
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
2010 Dec 09
4
Sequence generation in a table
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)
{
2011 Mar 09
3
Rearranging the data
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
2011 Mar 29
3
Reversing order of vector
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
2011 Aug 23
4
Correlation discrepancy
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
2010 Oct 27
4
One silly question about "tapply output"
Dear R helpers
I have a data which gives Month-wise and Rating-wise Rates. So the input file is something like
month rating rate
January AAA 9.04
February AAA 9.07
..........................................
..........................................
Decemeber AAA 8.97
January BBB 11.15
February
2011 Sep 14
2
Question regarding dnorm()
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
2012 May 22
3
What's wrong with MEAN?
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
2011 Mar 16
2
One to One Matching multiple vectors
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]]
2011 May 30
2
Value of 'pi'
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]]
2012 Apr 20
3
Matrix multiplication by multple constants
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
2011 Aug 25
1
Autocorrelation using acf
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.
2012 Sep 12
6
How to append the random no.s for different variables in the same data.frame
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,
2011 Mar 15
2
Matching two vectors
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
2011 Mar 21
2
Correlation for no of variables
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
2012 Jul 18
2
How to have original (name) order after melt and cast command
Dear R helpers,
I have a data.frame as given below -
dat1 = data.frame(date = as.Date(c("3/30/12","3/29/12","3/28/12","3/27/12","3/26/12",
"3/23/12","3/22/12","3/21/12","3/20/12", "3/30/12","3/29/12","3/28/12","3/27/12",
2011 Mar 12
2
Identifying unique pairs
Dear R helpers
Suppose I have a data frame as given below
mydat = data.frame(x = c(1,1,1, 2, 2, 2, 2, 2, 5, 5, 6), y = c(10, 10, 10, 8, 8, 8, 7, 7, 2, 2, 4))
mydat
x y
1 1 10
2 1 10
3 1 10
4 2 8
5 2 8
6 2 8
7 2 7
8 2 7
9 5 2
10 5 2
11 6 4
unique(mydat$x) will give me 1,
2010 Dec 30
1
Sorting data.frame datewise in a descending order
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",
2012 Jul 04
3
How to use Sys.time() while writing a csv file name
Dear R helpers,
I am using Beta distribution to generate the random no.s (recovery rates in my example). However, each time I need to save these random no.s in a csv format. To distinguish different csv files, one way I thought was use of Sys.time in the file name. My code is as follows -
# My code
rr = rbeta(25, 6.14, 8.12)
lgd = 1 - mean(rr)
write.csv(data.frame(recovery_rates = rr), file =