[R] covert entire dataset to numeric while persuing percentage values

[Jeff Newmiller]

I think you are getting ahead of yourself.

You use the term "dataset", which is colloquial and not precise. The read.csv function returns a data.frame, in which each column can have its own storage mode ("type"). Most data.frames do not have all columns of the same type... if they were you might consider converting to a matrix, but with different units in each column that would not be a good idea in this case.

>From your str output, I think you need to skip loading the second and third lines of your file in the first place, since it looks like they consist of unit strings. Something like:

fname <- file.choose()
xelements <- read.csv( fname, header=FALSE, skip=3, stringsAsFactors=FALSE)

but this does not get your column names. One way to get those would be:

names( xelements ) <- names( read.csv( fname ) )

As for the percent signs, you can convert those with something like:

xelements$ X..NG.by.Energy <- as.numeric( sub( "%". "", xelements$ X..NG.by.Energy ) )

In the future, please don't post in HTML format, as it just leads to confusion on this plain text mailing list. Read the Posting Guide for other warnings, and let us follow your journey to your problem with a reproducible example. There are various discussions online of what is reproducible.. you might start with [1]. Note that the read.csv function supports a "text" argument that lets you embed a sample of lines from your file into your example so we could troubleshoot your input process better if that is where your problem is.

[1] http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example

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On February 26, 2015 1:06:03 AM PST, "Methekar, Pushpa (GE Transportation, Non-GE)" <pushpa.methekar at ge.com> wrote:
>Hi ,
>I am little confused  about how to covert entire dataset to numeric .
>As I read data like..
>Xelements =read.csv(file. Choose(),header = T, stringsAsFactors=FALSE)
>str(xelements )
>
>> str(xelements)
>'data.frame':  731 obs. of  4 variables:
>$ Engine.Speed     : chr  "rpm" "ES" "rpm" "1049" ...
>$ X..NG.by.Energy  : chr  "" "% NG by Energy" "%" "0%" ...
>$ Int.Mfld.Temp    : chr  "" "Int Mfld Temp" "�C" "49" ...
>$ Cmd.Advance.Angle: chr  "" "Cmd Advance Angle" "�BTDC" "13.8" ...
>
>I have second column as in 0%, 10%,.... In percentage value ,
>Whenever I am going to covert whole dataset its showing NA introduced
>.second column going to become NA.
>Converting separately I would be successful .
>
>
>> xelements$Engine.Speed <- as.numeric(xelements$Engine.Speed)
>
>Warning message:
>
>NAs introduced by coercion
>
>> xelements$X..NG.by.Energy<-
>as.numeric(sub("%","",xelements$X..NG.by.Energy))/100
>
>Warning message:
>
>NAs introduced by coercion
>
>> xelements$Int.Mfld.Temp<- as.numeric(xelements$Int.Mfld.Temp)
>
>Warning message:
>
>NAs introduced by coercion
>
>> xelements$Cmd.Advance.Angle<- as.numeric(xelements$Cmd.Advance.Angle)
>
>Warning message:
>
>NAs introduced by coercion
>
>But I want to covert whole dataset at a time. I want to write function
>which will help me to solve this problem  .
>
>
>xelements <- data.frame(sapply(xelements, function(x)
>as.numeric(as.character(x))))
>sapply(xelements, class)
>
>but it won't be able to covert percentage value  like 10%, 20%....
>please do help me if you know the way. Thank you
>
>	[[alternative HTML version deleted]]
>
>
>
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