[R] unique and precision of long integers

Michael Herron mherron at latte.harvard.edu
Mon May 14 17:09:21 CEST 2001


Hello.

I have a dataset with about 500,000 observations, most of which are
not unique.  The first 10 observations look like

901000000000100000010100101011002
901101101110100000010100101011002
901000000000100000010100000001002
901000000000100000010101001011002
901000000000100000010101010011002
901000000000100000010100110101002
901000000000100000010100101011002
900000000000100000010010101011002
901000000000100000010100101101002
901000000000100000010100101011002

Each digit reflects a separate field, but above all spaces are
removed.

I read in the data with scan(), and then use unique() to get the
unique observations.  But, when I print these elements to a file I
lose precision.  For instance, let x be a vector of the first 10
observations from the dataset:

> write (x,file="output",ncol=1)

more output 

9.01e+32
9.011011e+32
9.01e+32
9.01e+32
9.01e+32
9.01e+32
9.01e+32
9e+32
9.01e+32
9.01e+32

Is there a way to get all the digits back?  

> write (format(x,digits=22),file="output",ncol=1) 

does not do it, and I cannot seem to increase digits >22.

thanks, 

michael
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