Displaying 3 results from an estimated 3 matches for "20080502l".
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20080502
2009 Mar 31
0
data.table is on CRAN (enhanced data.frame for time series joins and more)
...and the i
argument is like where, so this seems very natural (to me anyway!)
DT = data.table(a=letters[1:5], b=6:10)
setkey(DT,a)
identical(DT[J("d")], DT[4]) # binary search to row for 'd'
DT = data.table(id=rep(c("A","B"),each=3),
date=c(20080501L,20080502L,20080506L), v=1:6)
setkey(DT,id,date)
DT["A"] # all 3 rows for A since mult
by default is "all"
DT[J("A",20080502L)] # row for A where date also matches
exactly
DT[J("A",20080505L)] # NA...
2009 Mar 31
0
data.table is on CRAN (enhanced data.frame for time series joins and more)
...and the i
argument is like where, so this seems very natural (to me anyway!)
DT = data.table(a=letters[1:5], b=6:10)
setkey(DT,a)
identical(DT[J("d")], DT[4]) # binary search to row for 'd'
DT = data.table(id=rep(c("A","B"),each=3),
date=c(20080501L,20080502L,20080506L), v=1:6)
setkey(DT,id,date)
DT["A"] # all 3 rows for A since mult
by default is "all"
DT[J("A",20080502L)] # row for A where date also matches
exactly
DT[J("A",20080505L)] # NA...
2009 Apr 01
0
回复： R-help Digest, Vol 73, Issue 32
...and the i
argument is like where, so this seems very natural (to me anyway!)
DT = data.table(a=letters[1:5], b=6:10)
setkey(DT,a)
identical(DT[J("d")], DT[4]) # binary search to row for 'd'
DT = data.table(id=rep(c("A","B"),each=3),
date=c(20080501L,20080502L,20080506L), v=1:6)
setkey(DT,id,date)
DT["A"] # all 3 rows for A since mult
by default is "all"
DT[J("A",20080502L)] # row for A where date also matches
exactly
DT[J("A",20080505L)] # NA...