HI,
May be this helps:
record.length <- read.table(text = "NR length
1 100
2 130
3 150
4 148
5 100
6 83
7 60", sep="",header = TRUE)
valida.records <- read.table(text = "NR factor
1 3
2 4
4 8
7 9", sep="", header = TRUE)
indx<-diff(valida.records$NR)-1
skip.table<- within(valida.records, {skip<-
with(record.length,tapply(length,c(-1,rep(indx,indx+1)),function(x)
sum(x[-length(x)])))})[,c(1,3,2)]
skip.table
NR skip factor
#1 1 0 3
#2 2 0 4
#3 4 150 8
#4 7 183 9
A.K.
----- Original Message -----
From: Zhang Weiwu <zhangwe...@realss.com>
To: r-help@r-project.org
Cc:
Sent: Thursday, September 12, 2013 1:17 PM
Subject: [R] on how to make a skip-table
I've got two data frames, as shown below:
(NR means Number of Record)
> record.lenths
NR length
1 100
2 130
3 150
4 148
5 100
6 83
7 60
> valida.records
NR factor
1 3
2 4
4 8
7 9
And I intend to obtain the following skip-table:
> skip.table
NR skip factor
1 0 3
2 0 4
4 150 8
7 183 9
The column 'skip' is the space needed to skip invalid records.
For example, the 3rd element of skip.table has skip of '150', intended to
skip the invalid record No.3 in record.lengths
For example, the 4th element of skip.table has skip of '183', intended to
skip the invalid record No.5 and No.6, together is 100+83.
It's rather apparently intended for reading huge data files, and looks
simple math, and I admit I couldn't find an R-ish way doing it.
Thanks in advance and also thanks for pointing out if I had been on the
right track to start with.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
