Well, i am surprise you have problems to read a table that is "small" enough to
be opened entirely in Excel.
I work with csv tables with hundreds of thousands of rows, and sometimes even
millions .... with no problems except that sometimes i have to wait up to 1 or
2 minutes for R to read the table. I use the command read.csv.
If your tables are always small enough to be read in Excel, the limit of number
of rows in Excel is about 64000 or something of that sort (maybe 65000 ....) so
you can use this number as a limit for your number of rows .... although you
may have to "clean-up" your data.frame afterwards.
I work on a Windows machine with 4 Gb DRAM - just for comparison.
I hope this helps,
Monica
<Message: 88<Date: Wed, 29 Aug 2007 10:41:05 -0700<From: "Yuchen Luo" <[EMAIL
PROTECTED]><Subject: [R] How to signal the end of the table?<To:
r-help@stat.math.ethz.ch<Message-ID:<<[EMAIL PROTECTED]><<Content-Type:
text/plain<<I am using a "for" loop to read a table row by row and I have to
specify how<many records are there in the table. I need to read row by row
because the<table is huge and the memory not large enough for the whole
table.:<<<<number.of.records=100<<<<fp=file("abc.csv","r")<<pos=seek(fp,
rw="read")<<for (i in 1:number.of.record){<<current.row=scan(file=fp, sep=',',
what=list(count=1, cusip6="", idate=1,<spread=1.1, vol252=1.1, vol1000=1.1,
st_debt=1.1, lt_debt=1.1 , total_liab=<1.1, cr=1.1, shrout=1.1, prc=1.1,
mkt_cap=1.1, rtng=1.1, sec=1.1, cr3m=1.1,<cr5y=1.1, ust3m=1.1, ust5y=1.1),
flush=TRUE, nlines=1,quiet=T)<<...<<}<<<<I need to know the number of records
in the table and put it in the variable<named "nu!
mber.of.records". When I have a new table that I do not know how<many records
it has, I use excel to open the file to figure it out and put<it in variable "
number.of.records". I often have many tables to try and<every one of them has
thousands of records----it takes a lot of time and<trouble to adjust the code
every time I read a different table.<<<<I am wondering if I can change the
"for" loop to a "while" loop:<<<<while (the end of the table has not been
reached)<<{<<current.row=scan(file=fp, sep=',', what=list(count=1, cusip6="",
idate=1,<spread=1.1, vol252=1.1, vol1000=1.1, st_debt=1.1, lt_debt=1.1 ,
total_liab=<1.1, cr=1.1, shrout=1.1, prc=1.1, mkt_cap=1.1, rtng=1.1, sec=1.1,
cr3m=1.1,<cr5y=1.1, ust3m=1.1, ust5y=1.1), flush=TRUE,
nlines=1,quiet=T)<<...<<}<<<The problem is how to articulate "while (the end of
the table has not been<reached)", or equivalently, how to signal the end of the
table?<<Best Wishes<Yuchen Luo<< [[alternative HTML version deleted]]<
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