Displaying 20 results from an estimated 1000 matches similar to: "Identifying unique pairs"
2009 Aug 12
3
Obtaining the value of x at a given value of y in a smooth.spline object
I have some data fit to a smooth.spline object as follows: (x=vector of data
for the predictor variable, y=vector of data for the response variable)
fit <- smooth.spline(x,y)
Now, given a spline fit point y_new, I want to be able to find out what
value of x_new yielded this fit value. How to do so?
(This problem is the inverse of the predict.smooth.spline function, which
takes x_new as input
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",
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 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
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
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
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.
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
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
2012 Jul 19
3
Maintaining Column names while writing csv file.
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
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
2016 Jul 09
2
Red Neuronal complicada categorías
Hola,
Esta es una forma de hacerlo...
Mira que lo primero que he modificado es el fichero "x.csv" para sustituir
los espacios en los nombres por "_". Y también he quitado los acentos y las
eñes...
He utilizado el paquete RNNS y la función "mlp()" para ajustar la red.
#-------------------------------------------
> x <- read.csv("x.csv",