Identify YMD names in a character vector
grep for YMD (year, month, day) in
col.names. Return a named list of integer
vectors of length 3 for each triple found.
dateCols(col.names, YMD=c('Year', 'Month', 'Day'))col.names |
either a character vector in which to search
for names matching |
YMD |
a character vector of patterns to use in
|
The data sets from the
Correlates
of War project include dates coded in
triples of columns with names like
c("StartMonth1", "StartDay1",
"StartYear1", "EndMonth1", ..., "EndYear2").
This function will find all relevant date
triples in a character vector of column names
and return a list of integer vectors of
length 3 with names like
"Start1", "End1", ..., "End2" giving
the positions in col.names of the
desired date components.
Algorithm:
1. if(!is.null(colnames(YMD)))YMD <-
colnames(YMD)
2. ymd <- grep for YMD
(Year, Month, Day) in col.names.
3. groupNames <- sub
pattern with ” in ymd
4. Throw a warning for any
groupNames character string that
does not appear with all three of Year,
Month, and Day.
5. Return a list of integer vectors of length 3 for each triple found.
Returns a named list of integer vectors
of length 3 identifying the positions in
col.names of the desired date
components.
Spencer Graves
##
## 1. character vector
##
colNames <- c('war', 'StartMonth1',
'StartDay1', 'StartYear1',
'EndMonth1', 'EndMonth2',
'EndDay2', 'EndYear2', 'Initiator')
colNums <- dateCols(colNames)
# Should issue a warning:
# Warning message:
# In dateCols(colNames) :
# number of matches for Year = 2
# != number of matches for Month = 3
# check
colN <- list(Start1=c(Year=4, Month=2, Day=3),
End2=c(Year=8, Month=6, Day=7) )
all.equal(colNums, colN)
##
## 2. array
##
A <- matrix(ncol=length(colNames),
dimnames=list(NULL, colNames))
Anums <- dateCols(A)
# check
all.equal(Anums, colN)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.