[R] about data structure

Jeff Newmiller jdnewmil at dcn.davis.ca.us
Mon Nov 7 23:34:01 CET 2016

You have non-numeric data somewhere in that column, and factor is already a numeric type (Read about factors in the Introduction to R document that comes with R). Try 

DF$prec_new = as.numeric(as.character (DF$precip)

and then look at

DF$precip[ is.na( DF$precip_new ) ]

to see which values are corrupt. Eliminating the whole factor conversion in the first place might be as simple as adding an na.string argument to your read.table or read.csv call that imports the data.

If you need further help, next time send plain text format email with a reproducible example. 


Sent from my phone. Please excuse my brevity.

On November 7, 2016 12:24:57 PM PST, lily li <chocold12 at gmail.com> wrote:
>Hi R users,
>I'm wondering why the values changed when I try to transform factors
>For example, for a data frame DF, there is one column called
>which is usually lower than 100mm. But this column is factor when I
>read in
>the data. When transform to numeric values, some rows can be higher
>1000mm. What is the problem? Thanks.
>DF$prec_new = as.numeric(DF$precip)
>	[[alternative HTML version deleted]]
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