How do I get 10^4 to become 10000?

6 messages · Marc Schwartz, Patrick Connolly, Peter Dalgaard +1 more

Original

1

6

Patrick Connolly

Mon, Apr 21, 2003 6:51 PM #

Of course, that's as trivial as it gets on the command line, but I
can't work out how to get a column of numbers that are entered as
"10^5" from its 'character' format into a numeric one?

I feel a bit embarrassed asking such a simple question.  Too much
Easter....

Thanks

Patrick Connolly
HortResearch
Mt Albert
Auckland
New Zealand 
Ph: +64-9 815 4200 x 7188
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~
I have the world`s largest collection of seashells. I keep it on all
the beaches of the world ... Perhaps you`ve seen it.  ---Steven Wright 
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~

Mon, Apr 21, 2003 8:23 PM #

Connolly

For an individual value you can use:

[1] 1e+05


However, that simple approach does not work with a vector, since the
'text' argument is treated as if it were single lines in an input
file.  Thus you need to do something like this to loop through the
vector elements:

# create the character vector
cv <- c("10 ^ 5", "10 ^ 4", "10 ^ 8")

# function to convert char vector elements to numeric
convtext <- function(x) eval(parse(text = x))

# use sapply to convert the vector
sapply(cv, convtext, USE.NAMES = FALSE)
[1] 1e+05 1e+04 1e+08


HTH,

Marc Schwartz

Patrick Connolly

Mon, Apr 21, 2003 8:54 PM #

On Mon, 21-Apr-2003 at 10:23PM -0500, Marc Schwartz wrote:

|> For an individual value you can use:
|> 
|> > eval(parse(text = "10 ^ 5"))
|> [1] 1e+05
|> 
|> 
|> However, that simple approach does not work with a vector, since the
|> 'text' argument is treated as if it were single lines in an input
|> file.  Thus you need to do something like this to loop through the
|> vector elements:
|> 
|> # create the character vector
|> cv <- c("10 ^ 5", "10 ^ 4", "10 ^ 8")
|> 
|> # function to convert char vector elements to numeric
|> convtext <- function(x) eval(parse(text = x))
|> 
|> # use sapply to convert the vector
|> sapply(cv, convtext, USE.NAMES = FALSE)
|> [1] 1e+05 1e+04 1e+08

That's precisely what I needed to know.  Thanks

Thanks also to Tony Plate, Ray Brownrigg, and Robin Hankin for
reminding me of the 'text' argument to parse().

best

Patrick Connolly
HortResearch
Mt Albert
Auckland
New Zealand 
Ph: +64-9 815 4200 x 7188
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~
I have the world`s largest collection of seashells. I keep it on all
the beaches of the world ... Perhaps you`ve seen it.  ---Steven Wright 
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~

1 day later

Don MacQueen

Wed, Apr 23, 2003 7:14 AM #

How about this?

[1] 1.0e+05 1.2e+03 2.3e+00

This solution doesn't work for "10^(-5)" but does work for "10^-5".

-Don

At 1:51 PM +1200 4/22/03, Patrick Connolly wrote:

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--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA

Wed, Apr 23, 2003 8:42 AM #

Don MacQueen <macq at llnl.gov> writes:

Didn't work too well for 1.2^3 by some standards...

[1] 10000.000     1.728     2.300

O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907

Don MacQueen

Wed, Apr 23, 2003 9:11 AM #

Oops.
Red face here.
-Don

At 5:42 PM +0200 4/23/03, Peter Dalgaard BSA wrote:

--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA