Where do these numbers come from? If they are calculated values, they are 
actually many decimal places longer than your examples. They are represented on 
your terminal with fewer decimals according to the setting of 
options("digits"). 

For example:

> sqrt(2)*sqrt(2)
[1] 2
> sqrt(2)*sqrt(2) == 2  
[1] FALSE
# FAQ 7.31 Why doesn’t R think these numbers are equal?
> options("digits")
$digits
[1] 7
> options(digits=22)
> sqrt(2)*sqrt(2)
[1] 2.000000000000000444089

If the numbers were read from a plain text file and you are talking about how 
they are represented in the file, analyze them as character strings.

-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352

-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On 
Behalf Of PO SU
Sent: Thursday, October 23, 2014 10:35 PM
To: R. Help
Subject: [R] how to calculate a numeric's digits count?


Dear usRers,
  Now i want to cal ,e.g. 
 cal(1.234)  will get 3
 cal(1) will get 0
 cal(1.3045) will get 4
 But the difficult part is cal(1.3450) will get 4 not 3.
So, is there anyone happen to know the solution to this problem, or it can't be 
solved in R, because 1.340 will always be transformed autolly to 1.34?






--

PO SU
mail: desolato...@163.com 
Majored in Statistics from SJTU
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