R help - May 2012 - Numeric data not numeric in .csv file

I am a raw novice to R, playing around with a mini .csv dataset created in
Excel. I can read it in and the data looks OK in Excel and upon initial
inspection in R:

hikes <- read.csv("/Users/eproper/Desktop/hikes.csv", header=TRUE)
print(hikes)

does exactly what it is supposed to do.

Two of the variables are genuine strings, but the others ought to be
numeric, and R will calculate their min, max etc. However, is.numeric
returns FALSE for all of them; storage.mode returns "language."
as.numeric
returns "Error: 'pairlist' object cannot be coerced to type
'double'." In
what I suspect is a related problem, any command that calls for a variable
name requires an initial ~ to work. That is, instead of plot(miles) I have
to use plot(~miles).

No doubt there is some very elementary mistake I am making, but I can't
figure it out. Any help would be appreciated.

<http://theturducken.blogspot.com/>

	[[alternative HTML version deleted]]

Sounds like you have some text in your csv file. Open it with a text editor and
look at it. Some common problems are: alphabetic or symbol characters, spaces,
quotes around numbers. Also watch out for blank rows or columns.

Read the Posting Guide (mentioned at the bottom of every post). Tips: The dput
function is useful for generating an unambiguous representation of your data,
which is key in getting correct advice around here. The head function can be
used to chop off a short amount of data if you have a lot. The str function is
good for troubleshooting your own issues.
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Sent from my phone. Please excuse my brevity.

Eve Proper <eproper at gmail.com> wrote:
>I am a raw novice to R, playing around with a mini .csv dataset created
>in
>Excel. I can read it in and the data looks OK in Excel and upon initial
>inspection in R:
>
>hikes <- read.csv("/Users/eproper/Desktop/hikes.csv",
header=TRUE)
>print(hikes)
>
>does exactly what it is supposed to do.
>
>Two of the variables are genuine strings, but the others ought to be
>numeric, and R will calculate their min, max etc. However, is.numeric
>returns FALSE for all of them; storage.mode returns "language."
>as.numeric
>returns "Error: 'pairlist' object cannot be coerced to type
'double'."
>In
>what I suspect is a related problem, any command that calls for a
>variable
>name requires an initial ~ to work. That is, instead of plot(miles) I
>have
>to use plot(~miles).
>
>No doubt there is some very elementary mistake I am making, but I can't
>figure it out. Any help would be appreciated.
>
><http://theturducken.blogspot.com/>
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at 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.

On 05/02/2012 10:47 AM, Eve Proper wrote:
> I am a raw novice to R, playing around with a mini .csv dataset created in
> Excel. I can read it in and the data looks OK in Excel and upon initial
> inspection in R:
>
> hikes<- read.csv("/Users/eproper/Desktop/hikes.csv",
header=TRUE)
> print(hikes)
>
> does exactly what it is supposed to do.
>
> Two of the variables are genuine strings, but the others ought to be
> numeric, and R will calculate their min, max etc. However, is.numeric
> returns FALSE for all of them; storage.mode returns "language."
as.numeric
> returns "Error: 'pairlist' object cannot be coerced to type
'double'." In
> what I suspect is a related problem, any command that calls for a variable
> name requires an initial ~ to work. That is, instead of plot(miles) I have
> to use plot(~miles).
>
> No doubt there is some very elementary mistake I am making, but I can't
> figure it out. Any help would be appreciated.
>
Hi Eve,
Have you tried "as.numeric" on them? As Jeff suggested, you may be 
importing spaces along with the digits or some other character that 
changes the class of the variable. Also note that the default behavior 
of functions like read.csv is to coerce all of the values in a column of 
the resulting data frame to the "lowest common denominator". If you
have
one text value in a column of numbers, you usually get factor values. 
This is due to the restriction that all values in a column must be of 
the same class (data type).

Jim

On May 1, 2012, at 8:47 PM, Eve Proper wrote:
> I am a raw novice to R, playing around with a mini .csv dataset  
> created in
> Excel. I can read it in and the data looks OK in Excel and upon  
> initial
> inspection in R:
>
> hikes <- read.csv("/Users/eproper/Desktop/hikes.csv",
header=TRUE)
> print(hikes)
>
> does exactly what it is supposed to do.
>
> Two of the variables are genuine strings, but the others ought to be
> numeric, and R will calculate their min, max etc. However, is.numeric
> returns FALSE for all of them;
How did you do this? What code did you use? It should have been:

lapply(hikes, is.numeric)
> storage.mode returns "language."
Well, that suggests that you were trying to use unquoted variable  
names without the data objects name. Did you use attach() on the basis  
of some misguided instructions?

> as.numeric
> returns "Error: 'pairlist' object cannot be coerced to type  
> 'double'." In
> what I suspect is a related problem, any command that calls for a  
> variable
> name requires an initial ~ to work. That is, instead of plot(miles)  
> I have
> to use plot(~miles).
As I said, you are not correctly referencing column names within data  
objects.
>
> No doubt there is some very elementary mistake I am making, but I  
> can't
> figure it out. Any help would be appreciated.
>
> <http://theturducken.blogspot.com/>
>
> 	[[alternative HTML version deleted]]
And you should read the Posting Guide and correct your posting format.
>
> ______________________________________________
> R-help at 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.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT