Displaying 2 results from an estimated 2 matches for "tfdata_quarter".
2008 Jun 05
7
Improving data processing efficiency
...terssinceissue = function(tfdata,
quarters_since_issue=40) {
result = matrix(nrow=0, ncol=ncol(tfdata)) # rbind for matrix is
cheaper, so typecast the result to matrix
colnames = names(tfdata)
quarterends = sort(unique(tfdata$DATE))
for (aquarter in quarterends) {
tfdata_quarter = tfdata[tfdata$DATE == aquarter, ]
tfdata_quarter_fitting_nonissuers = tfdata_quarter[
(tfdata_quarter$Quarters.Since.Latest.Issue > quarters_since_issue) &
(tfdata_quarter$IPO.Flag == 0), ]
tfdata_quarter_ipoissuers = tfdata_quarter[
tfdata_quarter$IPO.Flag == 1, ]...
2008 Jun 06
6
Subsetting to unique values
I want to take the first row of each unique ID value from a data frame.
For instance
> ddTable <-
data.frame(Id=c(1,1,2,2),name=c("Paul","Joe","Bob","Larry"))
I want a dataset that is
Id Name
1 Paul
2 Bob
> unique(ddTable)
Will give me all 4 rows, and
> unique(ddTable$Id)
Will give me c(1,2), but not accompanied by the name column.