Displaying 20 results from an estimated 10000 matches similar to: "Adding a row at top of dataframe"
2010 Dec 16
2
Compare two dataframes
Hello,
I have two dataframes DF1 and DF2 that should be identical but are not
(DF1 has some rows that aren't in DF2, and vice versa). I would like
to produce a new dataframe DF3 containing rows in DF1 that aren't in
DF2 (and similarly DF4 would contain rows in DF2 that aren't in DF1).
I have a solution for this problem (see self contained example below)
but it's awkward and
2010 May 13
2
Adding name to nth row
Hello,
I have a data frame with many rows, and I want to create a column with
a name only at every 12th row, starting from 97 to 278.
Thanks in advance!
2010 May 26
2
How to calculate mean of means
I have 3 columns of numbers, and i want to find the mean of each
separately, and then the mean of all of the means.
ive tried:
av3daysB<- mean(mean(avr1), mean(avr2), mean(avr3))
av3daysB
but it only gives me the mean of the first column (avr1)
Any suggestions?
Thanks,
Emilija
2010 May 28
2
if negative value, make zero
I have a data frame with both positive and negative values, and I want
to make all the negative values equal zero, so i can eventually take
an average.
I've tried
temp2 <- ifelse(tempr<0, 0, tempr)
but it doesn't seem to work.
Any suggestions?
Thanks!
2010 Jun 09
1
[R-sig-Geo] How to extract coordinates values from a shapefile?
I'm not sure if this is what you want. But the function coordinates() in sp
package gives you the coordinates of SpatialObjects.
Regards.
Rodrigo.
2010/6/9 Nikhil Kaza <nikhil.list@gmail.com>
> You need to execute gpclibPermit() to enable gpclib.
>
> library(maptools) should have issued a warning to that effect.
>
>
> Nikhil Kaza
> Asst. Professor,
> City and
2010 May 04
1
Extract rows with non-zero elements
Dear all,
In my dataset I have 12 columns and 5824 rows. The second column contains
information about the height of a claim: it might be zero or positive. I
would like to do an analysis on the positive part of this matrix, but I do
need the other colums with this. So if there are like 1000 rows where the
second column is positive, I would like to extract this 1000x13 matrix into
another matrix.
2010 Jun 21
2
Calculating a daily average
I have a set of data with 12 readings for temperature per day, with
180 days. I want to find the average temperature of each day. I am
able to do this one by one, but with that many days to calculate the
average for, it will get very long. I'm sure there is a faster way to
do this, I just don't know how. What i have so far is:
av1 <- subset(ER9r, Day == 98, select = c
2010 Jul 19
2
replacing elements of distance matrix
Hi! I am trying to implement non-bipartite matching. I have around 500 sites
which can be clustered by 10 regions. I am able to calculate pairwise
Mahalanobis distances between sites (thanks to another post in the forum).
However, I want to constrain my match to sites within the same region. Thus
I want to replace elements of the distance matrix with a high value, say
999999, for sites not of the
2010 Aug 03
4
Need help on upper.tri()
HI, I am really messing up to make a symmetrical matrix using upper.tri() & lower.tri() function. Here is my code:
> set.seed(1)
> mat = matrix(rnorm(25), 5, 5)
> mat
[,1] [,2] [,3] [,4] [,5]
[1,] -0.6264538 -0.8204684 1.5117812 -0.04493361 0.91897737
[2,] 0.1836433 0.4874291 0.3898432 -0.01619026 0.78213630
[3,] -0.8356286 0.7383247
2010 Jun 20
3
Spatial: number of independent components?
Hi all, I am sorry if this is a very basic quesion, but I have no experience
with analyzing spatial data and could not find the right function/package
quickly. Any hints would be much appreciated. I have a matrix of spatial
point patterns like the one below and want to find the number of independent
components (if that's the right term) in that matrix (or in that image).
x=matrix(c(0,1,0,0,0,
2010 Jun 28
1
Subtraction loop
I have a data frame with 2 columns, one for day and one for average.
The day starts at 97 all the way to 279. I want to subtract day 98
average- day 97 average, then day99 average -day 98 average and so on
down my list, creating another column with the subtracted results.
I have:
Day DailyAverage
1 97 0.6076782
2 98 0.7121478
3 99 0.8059347
4 100 0.9545806
5
2009 Oct 22
1
Recode issue
I am having trouble with the recode function that is provided in the
CAR package. I trying to create a new factors based on existing factors.
E.g.
>x <- as.factor(1:20)
>y <- recode(x, " 1:5='A'; 6:10='B'; 11:15='C'; 16:20='D' ")
>y
[1] A A A A A 6 7 8 9 A A A A A A A A A A A
Levels: 6 7 8 9 A
Could someone point to me, my error?
2009 Nov 06
2
another question: how to delete one of columes in two ones with high correlation(0.95)
my programe is below:
a=c(1,2,1,1,1); b=c(1,2,3,4,1); c=c(3,4,3,3,3); d=c(1,2,3,5,1);
e=c(1,5,3,5,1)
data.f=data.frame(a,b,c,d,e)
origin.data<-data.f
cor.matrix<-cor(origin.data)
origin.cor<-cor.matrix
m<-0
for(i in 1:(cor.matrix[1]-1))
{
for(j in (i+1):(cor.matrix[2]))
{
if (cor.matrix[i,j]>=0.95)
{
data.f<-data.f[,-i];
i<-i+1
}
2010 Jul 28
2
Beginner stucked with raster + geoR package.
Hello everyone.
I am trying to build up understanding in R by trying to develop just some simple
scenarios.
I would like to explain you what I am trying to do and what I did so far.
I would like to put inside a RasterLayer (raster package) a Gaussian field (for
given covariance) using grf function (geoR package)
1. First I created a Raster Layer object
r <- raster() # Default values are
2010 Jul 13
1
Batch file export
Dear all,
I have a code that generates data vectors within R. For example assume:
z <- rlnorm(1000, meanlog = 0, sdlog = 1)
Every time a vector has been generated I would like to export it into a csv
file. So my idea is something as follows:
for (i in 1:100) {
z <- rlnorm(1000, meanlog = 0, sdlog = 1)
write.csv(z, "c:/z_i.csv")
Where "z_i.csv" is a filename that is
2010 Oct 20
1
help identifying clusters
Dear list:
I have a dataset of geographical data that looks like this example data:
dat<- data.frame( lon = c(rnorm(1000, mean=-10), rnorm(1000, mean=10),
rnorm(1000, mean=5)),
lat = c(rnorm(1000, mean=40), rnorm(1000, mean=30), rnorm(1000, mean=0)))
plot(dat$lon, dat$lat)
My positions are clearly clustered (in this example there are 3 clusters).
Is there any R algorithm that
allows me to
2010 Jul 25
1
Left Outer Join 2 DF's on Multiple Conditions
Hi,
I am trying to execute the following SQL statement using two data frames:
tab1, tab2 : Two Tables
Select tab1.*, tab2.*, tab1.tobiiTime - tab2.ruiTime as timeDiff,
IFNULL(n-m, -9999999) as alwaysIncrement
FROM tab1
LEFT OUTER JOIN tab2 On tab1.data1 - tab2.mouseX = 0 And tab1.data2 -
tab2.mouseY = 0
I am trying to do the following in R:-
*#Getting error here:*
data
2010 Jul 22
1
Updating a Data Frame
Hi,
I have a global data-frame in my R script.
At some point in my script, I want to update certain columns of this
data-frame by calling in an update function.
The function looks like this:
# get events data. This populates a global event data frame in the R-script
events <- getEvents(con, eventsFilePath)
# events has columns eventid, timeStamp, isSynchronized, timeDiff; with
millions of
2010 Aug 09
2
efficient matrix element comparison
It is a simple problem in that I simply want to convert the For loop to a more efficient method. It simply loops through a large vector checking if the numeric element is not equal to the index of that element. The following example demonstrates a simplified example:
> rows <- 10
> collusionM <- Matrix(0,10,10,sparse=TRUE)
> matchM <- matrix(c(1,2,3,4,4,6,7,9,9,10))
>
>
2010 Jul 07
1
Batch files process and String parsing
Here are what i am going to accomplish:
I have 400 files named as xxx.txt. the content of the file looks like the
following:
name count
1. aaa 100
2. bbb 2000
3. ccc 300
4. ddd 3000
........
more that 1000 rows in each files.
these are the areas i need help:
1. how can i only read in the files with the string patterns ggg or fff as
part of the file names?
for instance, I